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33 results on '"Jean-Louis Janeau"'

1. Experimental and modelling evidence of splash effects on manure borne Escherichia coli washoff

Author: Jean-Louis Janeau, Christian Valentin, Olivier Ribolzi, Thierry Henry-des-Tureaux, Keooudone Latsachack, Emma Rochelle-Newall, Chanthamousone Thammahacksa, Emilie Jardé, Claude Mügler, Marion Viguier, Oloth Sengtaheuanghoung, Modélisation Hydrologique (HYDRO), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Géosciences Environnement Toulouse (GET), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Institut d'écologie et des sciences de l'environnement de Paris (iEES Paris ), Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Géosciences Rennes (GR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), Department of Agricultural Land Management [Vientiane] (DALaM), Ministry of Agriculture and Forestry of Laos, Pastek program of the GIS-Climat, Institut de recherche pour le développement (IRD), Géosciences Environnement Toulouse, ANR-13-AGRO-0007,TecItEasy,Effets conjugués de l'expansion des plantations d'arbres et du changement climatique sur le fonctionnement hydro-sédimentaire des bassins versants tropicaux de montagne: la diversité microbienne aquatique comme un proxy de la conversion d'usage des terres(2013), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), and Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [SDV.SA]Life Sciences [q-bio]/Agricultural sciences, Runoff, Health, Toxicology and Mutagenesis, Faecal indicator bacteria (FIB), 010501 environmental sciences, Physics-based modelling, Raindrop impact, 01 natural sciences, complex mixtures, Lao PDR, Hydraulic conductivity, Environmental Chemistry, 0105 earth and related environmental sciences, 2. Zero hunger, Hydrology, Splash, fungi, Tropical agro-ecosystems, Sediment, General Medicine, Vegetation, 15. Life on land, Pollution, Manure, 6. Clean water, 13. Climate action, Soil water, Erosion, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Surface runoff
Abstract: International audience; In tropical montane South-East Asia, recent changes in land use have induced increased runoff, soil erosion and in-stream suspended sediment loads. Land use change is also contributing to increased microbial pathogen dissemination and contamination of stream waters. Escherichia coli (E. coli) is frequently used as an indicator of faecal contamination. Field rain simulations were conducted to examine how E. coli is exported from the surface of upland, agricultural soils during runoff events. The objectives were to characterize the loss dynamics of this indicator from agricultural soils contaminated with livestock waste, and to identify the effect of splash on washoff. Experiments were performed on nine 1 m2 plots, amended or not with pig or poultry manure. Each plot was divided into two 0.5 m2 sub-plots. One of the two sub-plots was protected with a mosquito net for limiting the raindrop impact effects. Runoff, soil detachment by raindrop impact and its entrainment by runoff, and E. coli loads and discharge were measured for each sub-plot. The results show that raindrop impact strongly enhances runoff generation, soil detachment and entrainment and E. coli export. When the impact of raindrops was reduced with a mosquito net, total runoff was reduced by more than 50%, soil erosion was on average reduced by 90% and E. coli export from the amended soil surface was on average 3 to 8 times lower. A coupled physics-based approach was performed using the Cast3M platform for modelling the time evolutions of runoff, solid particles detachment and transfer and bacteria transport that were measured for one of the nine plots. After estimation of the saturated hydraulic conductivity, soil erodibility and attachment rate of bacteria, model outputs were consistent with measured runoff coefficients, suspended sediment and E. coli loads. This work therefore underlines the need to maintain adequate vegetation at the soil surface to avoid the erosion and export of soil borne potential pathogens towards downstream aquatic systems.
Published: 2021
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2. Water uptake plasticity of savanna trees in encroached grassland: small trees match the mature trees

Author: Patricia Richard, Séraphine Grellier, David Ward, Thierry Bariac, Simon Lorentz, Nicolas Florsch, Jean-Louis Janeau, Cités, Territoires, Environnement et Sociétés (CITERES), Centre National de la Recherche Scientifique (CNRS)-Université de Tours, Institut d'écologie et des sciences de l'environnement de Paris (iEES Paris ), Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Paléocéanographie (PALEOCEAN), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Tours (UT)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), and Centre National de la Recherche Scientifique (CNRS)-Université de Tours (UT)
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, [SDE.MCG]Environmental Sciences/Global Changes, Vachellia sieberiana, 010603 evolutionary biology, 01 natural sciences, Grassland, South Africa, Water uptake, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, ComputingMilieux_MISCELLANEOUS, isotopes, 0105 earth and related environmental sciences, 2. Zero hunger, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, geography, geography.geographical_feature_category, Ecology, 15. Life on land, Agronomy, Soil water, Environmental science, Animal Science and Zoology, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, oxygen 18, Woody plant, encroachment
Abstract: International audience; Processes linked to woody plant encroachment in grassland are still not well understood, especially the interactions between trees and soil water availability. Our aim was to study the depth of water uptake by trees in grassland and its controlling factors. We studied water uptake in Vachellia sieberiana trees (hereafter called 'acacias') in a humid grassland of South Africa. We especially studied the effect of size classes of acacias and their position in the catena on water potential (ψ) of acacia leaves and water uptake depth of acacias across seasons, as inferred from isotope δ 18 O values of soil and stem water samples. Acacias were more water stressed in February (wet season) with the most negative water potentials. Taller acacias (>3 m height) were more water-stressed (ψ ± SD = −1.62 ± 0.81 MPA) than smaller acacias (
Published: 2020
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3. Research for development in the 21st century

Author: T.M. Tran, Jean-Louis Janeau, S. Cheik, Ajay Harit, Vannak Ann, M. Calabi Floody, Thuy Thu Doan, Cornelia Rumpel, Q. A. Ngo, Muhammad Sanaullah, P. L. Rossi, María de la Luz Mora, Pascal Jouquet, P. Podwojewski, H. Bahri, Institut d'écologie et des sciences de l'environnement de Paris (iEES Paris ), Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Institute of Technology of Cambodia [Cambodge] (KHM), Soils and Fertilizers Research Institute (SFRI), Vietnam Academy of Agricultural Sciences (VAAS), Institute of Geological Sciences [Hanoi] (VAST), Vietnam Academy of Science and Technology (VAST), University of Agriculture Faisalabad (UAF), and Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)
Subjects: 2019-20 coronavirus outbreak, Coronavirus disease 2019 (COVID-19), Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), [SDV]Life Sciences [q-bio], 05 social sciences, 0507 social and economic geography, Soil Science, 04 agricultural and veterinary sciences, Virology, Article, Political science, 040103 agronomy & agriculture, 0401 agriculture, forestry, and fisheries, 050703 geography
Published: 2020
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4. Mechanisms of lateral and linear extension of gullies (dongas) in a subhumid grassland of South Africa

Author: Sandrine Caquineau, Pascal Podwojewski, J.C. Hughes, Jean-Louis Janeau, Institut d'écologie et des sciences de l'environnement de Paris (iEES Paris ), Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Variabilité à long terme du climat de l'océan (VALCO), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), School of Agricultural, Earth and Environmental Sciences (SAEES), University of KwaZulu-Natal [Durban, Afrique du Sud] (UKZN), Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU), and University of KwaZulu-Natal (UKZN)
Subjects: 010504 meteorology & atmospheric sciences, Geography, Planning and Development, Soil science, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], 01 natural sciences, rangeland, gully extension, South Africa, Earth and Planetary Sciences (miscellaneous), Water content, 0105 earth and related environmental sciences, Earth-Surface Processes, Colluvium, Horizon (geology), Topsoil, shrink-swell, Soil classification, 04 agricultural and veterinary sciences, 15. Life on land, soil properties, Soil water, 040103 agronomy & agriculture, 0401 agriculture, forestry, and fisheries, Soil horizon, Surface runoff, Geology
Abstract: International audience; The formation of deep gullies (called ‘dongas’ locally) in rangeland in KwaZulu‐Natal Province in South Africa is a natural phenomenon. These U‐shaped, very wide gullies have considerable lateral expansion due to the episodic collapse of sidewalls.The dongas have developed in duplex soils such as Luvisols and Lixisols formed on Permian sedimentary rocks or unconsolidated Quaternary colluvium. This study combined morphological, mineralogical and chemical characterization with measurements of grain‐size content, structural stability and the complete shrinkage curve to detect changes in soil properties of the different horizons located in the gully banks.The different soil horizons present clear and sharp differences in physical and mineralogical properties. The topsoil with complete grass cover is very resistant to soil detachment. However, the leached E horizon and the BC horizon have low structural stability. The soil profile down to and including the Bt horizon contains exclusively illite in the clay fraction, while the BC colluvial layer and the C horizon (mudstone) contain expandable interstratified illite–smectite. The Bt horizon has a high water content at saturation and high shrinkage, while the BC and C horizons have a high residual shrinkage and a very low water content at saturation.Because this type of gully expansion is not significantly linked to slope value or the stream power index (SPI) at the gully head, to land‐use change, high rainfall intensities or the threshold of concentrated runoff being exceeded at the gully head, other causes were investigated. It was concluded that the heterogeneity between horizons with different mineralogical properties and structural stabilities, soil types and parent material, anisotropic water‐saturation and shrink‐swell properties are of major importance. This heterogeneity between different soil horizon morphologies and their physical properties can explain why the relationship between the critical slope and the drainage area for gully initiation showed a threshold for gullying much lower than that found elsewhere.
Published: 2020
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5. Higher runoff and soil detachment in rubber tree plantations compared to annual cultivation is mitigated by ground cover in steep mountainous Thailand

Author: Anneke de Rouw, Margot Neyret, Thibaut Durand, Juraiporn Kaewthip, Karn Trisophon, Jean-Louis Janeau, Christian Valentin, Henri Robain, Institut d'écologie et des sciences de l'environnement de Paris (iEES Paris ), Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), School of Computing Science, Simon Fraser University (SFU.ca), Land Development Department (LDD), and Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)
Subjects: Wet season, 010504 meteorology & atmospheric sciences, Ground cover, 01 natural sciences, Rubber trees, Natural rubber, Soil retrogression and degradation, Afforestation, Land use change, 0105 earth and related environmental sciences, Earth-Surface Processes, 2. Zero hunger, 04 agricultural and veterinary sciences, Understory, 15. Life on land, Plant litter, Steep slopes, Agronomy, visual_art, [SDE]Environmental Sciences, 040103 agronomy & agriculture, visual_art.visual_art_medium, Soil erosion, 0401 agriculture, forestry, and fisheries, Environmental science, Surface runoff, Soil conservation, Soil detachment
Abstract: Due to high rainfall erosivity and rapid land-use changes, South-East Asia is one of the hot spots of soil degradation worldwide. In recent decades, several studies showed that the expansion of rubber tree (RT) plantations into previously forested areas has caused a major increase in soil erosion. However, the effects of cropland conversion to RT plantations on surface runoff and soil detachment are still unclear. Here we show that mature RT plantations considerably increase runoff and soil detachment compared to annual crops or young RT plantations with intercrop, mostly due to the absence of understorey. Monitoring 1 m2 microplots over four years in mountainous Northern Thailand, we found that runoff and detachment increased with time since the onset of the rainy season and with rainfall height, but more so in mature RT plantations than in young RT plantations and maize. This led to much higher annual soil detachment in mature RT plantations (5.7 kg/m2 on average) than in maize and young RT plantations with intercrop (0.36 kg/m2). We identified two main factors explaining this difference: first, rubber tree leaf litter, although abundant, seemed ineffective in reducing runoff at the end of the rainy season. Secondly, the cover by low-growing plants in mature rubber tree plantation was usually sparse and provided little protection. In particular we showed that increasing the cover by low-growing plants from quasi-null cover to >31% cover decreased runoff coefficient by 32%. Our results demonstrate that afforestation by RT, at least under current management practices and on steep slopes, is overall detrimental to soil conservation but that its effects could be mitigated by the adoption of less intense weeding practices.
Published: 2020
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6. Land use strongly influences soil organic carbon and bacterial community export in runoff in tropical uplands

Author: Sylvain Huon, Olivier Ribolzi, Thomas Pommier, Huong T. Le, Keooudone Latsachack, Jean-Louis Janeau, Emma Rochelle-Newall, Vietnam Academy of Science and Technology (VAST), Laboratoire d'Ecologie Microbienne - UMR 5557 (LEM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Ecole Nationale Vétérinaire de Lyon (ENVL)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Institut d'écologie et des sciences de l'environnement de Paris (iEES Paris), Institut National de la Recherche Agronomique (INRA)-Sorbonne Université (SU)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées, Soils and Fertilizers Research Institute (SFRI), Vietnam Academy of Agricultural Sciences (VAAS), UMR 242, Institut de Recherche pour le Développement (IRD [France-Ouest]), Institut de Recherche pour le Développement, Partenaires INRAE, French National Research Agency (ANR) ANR-13-AGRO-0007, ANR-13-AGRO-0007,TecItEasy,Effets conjugués de l'expansion des plantations d'arbres et du changement climatique sur le fonctionnement hydro-sédimentaire des bassins versants tropicaux de montagne: la diversité microbienne aquatique comme un proxy de la conversion d'usage des terres(2013), Institut d'écologie et des sciences de l'environnement de Paris (iEES Paris ), and Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)
Subjects: [SDV]Life Sciences [q-bio], Soil Science, 010501 environmental sciences, Development, unsustainable land use, 01 natural sciences, complex mixtures, Soil functions, Dissolved organic carbon, Environmental Chemistry, Nitrogen cycle, 0105 earth and related environmental sciences, General Environmental Science, 2. Zero hunger, Total organic carbon, soil erosion, land degradation, 04 agricultural and veterinary sciences, Soil carbon, 15. Life on land, Soil quality, Agronomy, rain simulation, 13. Climate action, bacterial function, [SDE]Environmental Sciences, 040103 agronomy & agriculture, 0401 agriculture, forestry, and fisheries, Environmental science, Surface runoff, Surface water
Abstract: Early Access: NOV 2019; International audience; Rapid development and associated land-use change have resulted in increased soil erosion and widespread land degradation in tropical ecosystems. Precipitation-induced soil erosion causes the export of soil organic carbon (SOC) and the associated bacterial community affecting soil quality and functioning. We assessed the transfer of SOC and soil bacterial diversity and functions in surface water runoff from different land uses: Teak with and without understory (TW and TWO, respectively) and upland rice (UR) in a tropical, upland catchment during a simulated rain event. Total suspended sediment (TSS) concentration was higher in TWO (1.23 +/- 0.21 g L-1) than in TW (0.37 +/- 0.16 g L-1) and UR (0.44 +/- 0.2 g L-1), whereas dissolved organic carbon (DOC) concentration was lower under TWO (3.8 +/- 0.7 mg L-1) than under TW or UR (13.4 +/- 7.5 and 9.57 +/- 4.8 mg L-1, respectively). Runoff from TWO harboured the highest proportion of bacterial taxa common to soil (27% and 29.5%) as compared with TW (22.8% and 13%) and UR (17.3% and 7%) for both particle attached and free-living fractions, respectively. Bacterial community export in surface runoff was driven by changes in DOC and TSS, suggesting that eroded soil particles simultaneously carry organic carbon and attached bacterial taxa in surface runoff. Consequently, the export of soil functional groups relating to organic carbon degradation and nitrogen cycle was higher under TWO than in TW or UR. Our results underline that teak plantations with unsustainable practices such as the removal of understory degrades soil functions and accelerates land degradation through soil erosion and surface runoff on the long term.
Published: 2020
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7. Experimental and modelling evidence of short-term effect of raindrop impact on hydraulic conductivity and overland flow intensity

Author: Chanthamousone Thammahacksa, Claude Mügler, Marion Viguier, Keooudone Latsachack, Emilie Jardé, Emma Rochelle-Newall, Olivier Ribolzi, Thierry Henri-des-Tureaux, Christian Valentin, Oloth Sengtaheuanghoung, Jean-Louis Janeau, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Modélisation Hydrologique (HYDRO), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Géosciences Environnement Toulouse (GET), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Institut d'écologie et des sciences de l'environnement de Paris (iEES Paris), Institut National de la Recherche Agronomique (INRA)-Sorbonne Université (SU)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Géosciences Rennes (GR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Centre National de la Recherche Scientifique (CNRS), Agriculture Land-Use Planning Center, Agence Nationale de la Recherche, IRD, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), and Institut d'écologie et des sciences de l'environnement de Paris (IEES (UMR_7618 / UMR_D_242 / UMR_A_1392 / UM_113) )
Subjects: 010504 meteorology & atmospheric sciences, Hydraulic conductivity, 0207 environmental engineering, Soil science, 02 engineering and technology, Raindrop impact, 01 natural sciences, GEOF, Soil crusting, Hydrology (agriculture), Lao PDR, Runoff modelling, [SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology, 020701 environmental engineering, Water pollution, 0105 earth and related environmental sciences, Water Science and Technology, Splash, Tropical agro-ecosystems, 15. Life on land, 6. Clean water, Soil conditioner, Soil water, Erosion, Environmental science, Surface runoff
Abstract: International audience; Tropical montane areas of Southeast Asia are exposed to high-intensity rainfall during the monsoon period. This is particularly problematic in areas where soils on steep slopes are cultivated as it can lead to heavy runoff, high soil erosion, and water pollution. The objective of this paper is to analyse the effect of the impact of raindrops on the dynamics of runoff on such steep fields. Experiments under simulated rainfall were performed at the plot scale (1 m2) to quantify water export from the surface of upland agricultural soils during overland flow events. Four 1 m2 plots were divided in duplicated treatment groups: (a) control with no amendments, and (b) amended with pig manure. Each plot was divided into two 0.5 m2 rectangular subplots. One subplot was designated as a rain splash treatment; the other sub-plot was covered with a 2 mm grid size wire screen that was located 12 cm above the soil surface. The purpose of the screen was to break the raindrops into fine droplets and to reduce fall height in order to drastically reduce their kinetic energy. Runoff was measured for each sub-plot. The results show that raindrop impact drastically enhances runoff generation on both bare soils and on manure amended soils. When the impact of raindrops was limited by screening, runoff was higher on amended soils than on bare soils.The temporal evolution of runoff was correctly modelled using a soil hydraulic conductivity that exponentially decreases over time of exposure to rainfall. Both experimental and modelling results showed that droplet energy induces a rapid evolution of the hydraulic properties of the soil surface due to crusting, resulting in a reduction of hydraulic conductivity and a concomitant increase in runoff rate.
Published: 2019
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8. Effect of land use and hydrological processes on Escherichia coli concentrations in streams of tropical, humid headwater catchments

Author: Laurie Boithias, Bounsamay Soulileuth, Norbert Silvera, Olivier Ribolzi, Pem Sisouvanh, Nikom Hmaimum, Keooudone Latsachack, Henri Robain, Hai Tran Sy, Rinh Pham Dinh, Marion Viguier, Jean-Louis Janeau, Piyapong Naporn, Christian Valentin, Emma Rochelle-Newall, Chanthamousone Thammahacksa, Alain Pierret, Institut d'écologie et des sciences de l'environnement de Paris (iEES), Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Géosciences Environnement Toulouse (GET), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement, Partenaires INRAE, Soils & Fertilizers Res Inst, Duc Thang Ward, Hanoi, Vietnam, Natl Pk Wildlife & Plant Conservat Dept NPD, 61 Phaholyotin Rd, Bangkok 10900, Thailand, National Park, Wild Life and Plant Conservation Department (DNP), National Park Wild Life and Plant Conservation Department, National University of Laos, French ANR 'Teciteasy' [ANR-13-AGRO-0007], French Institut de Recherche pour le Developpement (IRD) through the ECOFILTER project (LMI LUSES), UMR iEES-Paris, UMR GET, Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Recherche Agronomique (INRA), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), and Rochelle-Newall, Emma
Subjects: Rain, [SDV]Life Sciences [q-bio], 0208 environmental biotechnology, 02 engineering and technology, 010501 environmental sciences, 01 natural sciences, Feces, contamination, afforestation, Vegetation type, Dry season, Multidisciplinary, Ecology, Agriculture, stormwater runoff, health, Vegetation, Thailand, field, 6. Clean water, Catchment hydrology, Vietnam, Laos, [SDE]Environmental Sciences, Seasons, Water Microbiology, Environmental Monitoring, Wet season, fecal indicator bacteria, STREAMS, Article, Hydrology (agriculture), Water Supply, Escherichia coli, Animals, Humans, Developing Countries, soils, 0105 earth and related environmental sciences, northern vietnam, Hydrology, Tropical Climate, rivers, waters, Humidity, 15. Life on land, Bacterial Load, 020801 environmental engineering, 13. Climate action, Environmental science, Surface runoff
Abstract: Lack of access to clean water and adequate sanitation continues to be a major brake on development. Here we present the results of a 12-month investigation into the dynamics of Escherichia coli, a commonly used indicator of faecal contamination in water supplies, in three small, rural catchments in Laos, Thailand and Vietnam. We show that land use and hydrology are major controlling factors of E. coli concentrations in streamwater and that the relative importance of these two factors varies between the dry and wet seasons. In all three catchments, the highest concentrations were observed during the wet season when storm events and overland flow were highest. However, smaller peaks of E. coli concentration were also observed during the dry season. These latter correspond to periods of intense farming activities and small, episodic rain events. Furthermore, vegetation type, through land use and soil surface crusting, combined with mammalian presence play an important role in determining E. coli loads in the streams. Finally, sampling during stormflow revealed the importance of having appropriate sampling protocols if information on maximum contamination levels is required as grab sampling at a fixed time step may miss important peaks in E. coli numbers.
Published: 2016
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9. Seasonal variability of faecal indicator bacteria numbers and die-off rates in the Red River basin, North Viet Nam

Author: Huong Thi Mai Nguyen, Josette Garnier, Quynh Thi Phuong Le, Jean-Louis Janeau, Emma Rochelle-Newall, Vietnam Academy of Science and Technology (VAST), Institut d'écologie et des sciences de l'environnement de Paris (iEES), Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Milieux Environnementaux, Transferts et Interactions dans les hydrosystèmes et les Sols (METIS), Université Pierre et Marie Curie - Paris 6 (UPMC)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Soils and Fertilizers Research Institute (SFRI), Vietnam Academy of Agricultural Sciences (VAAS), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Recherche Agronomique (INRA), Institut d'écologie et des sciences de l'environnement de Paris (IEES), Université Pierre et Marie Curie - Paris 6 (UPMC)-École pratique des hautes études (EPHE)-Centre National de la Recherche Scientifique (CNRS), and Université Pierre et Marie Curie - Paris 6 (UPMC)-École Pratique des Hautes Études (EPHE)
Subjects: Wet season, Veterinary medicine, 0208 environmental biotechnology, Population, Drainage basin, 02 engineering and technology, 010501 environmental sciences, 01 natural sciences, Article, Feces, Enterobacteriaceae, Rivers, [SDV.MHEP.MI]Life Sciences [q-bio]/Human health and pathology/Infectious diseases, Escherichia coli, Humans, Water pollution, education, 0105 earth and related environmental sciences, education.field_of_study, geography, Multidisciplinary, geography.geographical_feature_category, biology, Ecology, Water Pollution, Annual cycle, biology.organism_classification, 020801 environmental engineering, Coliform bacteria, Vietnam, Indicator species, Seasons, Water Microbiology, Bacteria, Environmental Monitoring
Abstract: The Red River is the second largest river in Viet Nam and constitutes the main water source for a large percentage of the population of North Viet Nam. Here we present the results of an annual survey of Escherichia coli (EC) and Total Coliforms (TC) in the Red River basin, North Viet Nam. The objective of this work was to obtain information on faecal indicator bacteria (FIB) numbers over an annual cycle and, secondly, to determine the die-off rates of these bacterial indicators. Monthly observations at 10 stations from July 2013–June 2014 showed that TC and EC reached as high as 39100 cfu (colony forming units) 100 ml−1 and 15300 colonies 100 ml−1, respectively. We observed a significant seasonal difference for TC (p −1 to a maximum of 1.13 d−1 for EC and from 0.17 d−1 to 1.33 d−1 for TC. Die-off rates were significantly higher for free bacteria than for total (free + particle attached) bacteria, suggesting that particle attachment provided a certain level of protection to FIB in this system.
Published: 2016
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10. Contradictory hydrological impacts of afforestation in the humid tropics evidenced by long-term field monitoring and simulation modelling

Author: Didier Orange, Olivier Ribolzi, Jean-Louis Janeau, Henri Robain, Alain Pierret, Christian Valentin, Guillaume Lacombe, Toan Tran Duc, Keoudone Latsachak, Adrien Taccoen, Rinh Pham Dinh, Anneke de Rouw, Phouthamaly Sengphaathith, Emmanuel Mouche, Norbert Silvera, Bounsamai Soulileuth, Oloth Sengtaheuanghoung, International Water Management Institute [CGIAR, Laos] (IWMI), International Water Management Institute [CGIAR, Sri Lanka] (IWMI), Consultative Group on International Agricultural Research [CGIAR] (CGIAR)-Consultative Group on International Agricultural Research [CGIAR] (CGIAR), Géosciences Environnement Toulouse (GET), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Institut d'écologie et des sciences de l'environnement de Paris (iEES Paris ), Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Soils and Fertilizers Research Institute (SFRI), Vietnam Academy of Agricultural Sciences (VAAS), Ecologie fonctionnelle et biogéochimie des sols et des agro-écosystèmes (UMR Eco&Sols), Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA), Laboratoire d'Etudes des Ressources Forêt-Bois (LERFoB), Ecole Nationale du Génie Rural, des Eaux et des Forêts (ENGREF)-Institut National de la Recherche Agronomique (INRA), University of Arizona, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Modélisation Hydrologique (HYDRO), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Ministry of Agriculture and Forestry of Laos, Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Géosciences Environnement Toulouse ( GET ), Institut de Recherche pour le Développement ( IRD ) -Université Paul Sabatier - Toulouse 3 ( UPS ) -Observatoire Midi-Pyrénées ( OMP ) -Centre National de la Recherche Scientifique ( CNRS ), Institut d'écologie et des sciences de l'environnement de Paris ( IEES ), Institut National de la Recherche Agronomique ( INRA ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Université Paris-Est Créteil Val-de-Marne - Paris 12 ( UPEC UP12 ) -Centre National de la Recherche Scientifique ( CNRS ), Institut de Recherche pour le Développement ( IRD [France-Ouest] ), Centre de Recherches Interculturelles sur les Domaines Anglophones et Francophones ( CRIDAF ), Université Paris 13 ( UP13 ) -Université Sorbonne Paris Cité ( USPC ), Laboratory of Molecular Neuro-oncology, Howard Hughes Medical Institute ( HHMI ) -The Rockefeller University, Representation du Laos ( IRD ), Unité GEOVAST, Institut de Recherche pour le Développement ( IRD ), Laboratoire de minéralogie, cristallographie de Paris ( LMCP ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -IPG PARIS-Université Paris Diderot - Paris 7 ( UPD7 ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] ( LSCE ), Université de Versailles Saint-Quentin-en-Yvelines ( UVSQ ) -Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay-Centre National de la Recherche Scientifique ( CNRS ), Department of Agricultural Land Management ( DALaM ), Soils and Fertilizers Research Institute ( SFRI ), VAAS, Laboratoire Chrono-environnement ( LCE ), Université Bourgogne Franche-Comté ( UBFC ) -Université de Franche-Comté ( UFC ) -Centre National de la Recherche Scientifique ( CNRS ), Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Institut d'écologie et des sciences de l'environnement de Paris (IEES), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Recherche Agronomique (INRA), Institut de Recherche pour le Développement (IRD [France-Ouest]), Centre de Recherches Interculturelles sur les Domaines Anglophones et Francophones (CRIDAF), Université Paris 13 (UP13)-Université Sorbonne Paris Cité (USPC), Howard Hugues Medical Institute-The Rockefeller University, Representation du Laos (IRD), Institut de Recherche pour le Développement (IRD), Laboratoire de minéralogie, cristallographie de Paris (LMCP), Université Pierre et Marie Curie - Paris 6 (UPMC)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), Department of Agricultural Land Management (DALaM), Laboratoire Chrono-environnement - UFC (UMR 6249) (LCE), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)
Subjects: [ SDU.OCEAN ] Sciences of the Universe [physics]/Ocean, Atmosphere, 010504 meteorology & atmospheric sciences, Tree planting, 0208 environmental biotechnology, Conservation des sols, 02 engineering and technology, 01 natural sciences, lcsh:Technology, Water balance, Shifting cultivation, Tectona grandis, Afforestation, Forêt tropicale humide, lcsh:Environmental technology. Sanitary engineering, Hydrologie, ComputingMilieux_MISCELLANEOUS, lcsh:Environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, 2. Zero hunger, lcsh:GE1-350, lcsh:Geography. Anthropology. Recreation, Plantation forestière, Reconstitution forestière, lcsh:TD1-1066, Water conservation, Conservation de l'eau, Streamflow, [ SDU.ENVI ] Sciences of the Universe [physics]/Continental interfaces, environment, Hydrometeorology, P10 - Ressources en eau et leur gestion, [SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, 0105 earth and related environmental sciences, P36 - Érosion, conservation et récupération des sols, Hydrology, lcsh:T, Régénération naturelle, 15. Life on land, K10 - Production forestière, 020801 environmental engineering, Water resources, lcsh:G, 13. Climate action, Environmental science
Abstract: The humid tropics are exposed to an unprecedented modernisation of agriculture involving rapid and mixed land-use changes with contrasted environmental impacts. Afforestation is often mentioned as an unambiguous solution for restoring ecosystem services and enhancing biodiversity. One consequence of afforestation is the alteration of streamflow variability which controls habitats, water resources, and flood risks. We demonstrate that afforestation by tree planting or by natural forest regeneration can induce opposite hydrological changes. An observatory including long-term field measurements of fine-scale land-use mosaics and of hydrometeorological variables has been operating in several headwater catchments in tropical southeast Asia since 2000. The GR2M water balance model, repeatedly calibrated over successive 1-year periods and used in simulation mode with the same year of rainfall input, allowed the hydrological effect of land-use change to be isolated from that of rainfall variability in two of these catchments in Laos and Vietnam. Visual inspection of hydrographs, correlation analyses, and trend detection tests allowed causality between land-use changes and changes in seasonal streamflow to be ascertained. In Laos, the combination of shifting cultivation system (alternation of rice and fallow) and the gradual increase of teak tree plantations replacing fallow led to intricate streamflow patterns: pluri-annual streamflow cycles induced by the shifting system, on top of a gradual streamflow increase over years caused by the spread of the plantations. In Vietnam, the abandonment of continuously cropped areas combined with patches of mix-trees plantations led to the natural re-growth of forest communities followed by a gradual drop in streamflow. Soil infiltrability controlled by surface crusting is the predominant process explaining why two modes of afforestation (natural regeneration vs. planting) led to opposite changes in streamflow regime. Given that commercial tree plantations will continue to expand in the humid tropics, careful consideration is needed before attributing to them positive effects on water and soil conservation.
Published: 2016
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11. Mixing of biochar with organic amendments reduces carbon removal after field exposure under tropical conditions

Author: Cornelia Rumpel, Pascal Jouquet, Dinh-Kim Dang, Thu Thuy Doan, Phuong Thi Ngo, Jean-Louis Janeau, Universidad de la Frontera (UFRO), Laboratoire Sols et Environnement (LSE), Institut National de la Recherche Agronomique (INRA)-Université de Lorraine (UL), Institut d'écologie et des sciences de l'environnement de Paris (iEES), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Recherche Agronomique (INRA), Centre National de la Recherche Scientifique (CNRS), Soils and Fertilizers Research Institute (SFRI), Vietnam Academy of Agricultural Sciences (VAAS), Institut de Recherche pour le Développement (IRD [France-Ouest]), Vietnam Academy of Sciences and Technology, International Joint Laboratory Indo-French Cell for Water Sciences (IFCWS), Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Université de Lorraine (UL), and Institut d'écologie et des sciences de l'environnement de Paris (IEES)
Subjects: compost, Environmental Engineering, vermicompost, [SDV]Life Sciences [q-bio], Tropical condition, 010501 environmental sciences, Management, Monitoring, Policy and Law, engineering.material, 01 natural sciences, Civil Engineering, Slash-and-char, tropical condition, Tropical climate, Biochar, Leaching (agriculture), Incubation, 0105 earth and related environmental sciences, Nature and Landscape Conservation, 2. Zero hunger, Chemistry, Compost, 04 agricultural and veterinary sciences, 15. Life on land, erosion, Manure, leaching, Agronomy, Erosion, Environmental chemistry, 040103 agronomy & agriculture, engineering, Leaching, 0401 agriculture, forestry, and fisheries, Vermicompost
Abstract: This study aimed to evaluate the decomposition of three exogenous organic amendments (buffalo manure, its compost and vermicompost), mixed with biochar or not, under tropical climate conditions. Litterbags containing pure substrates or mixtures were exposed to soil under natural rainfall conditions during one year. Most of C and N of exogenous organic matters (EOMs) and biochar were removed rapidly in the first 16 weeks of incubation. After one year, in case of applying alone, only around 30% of C of EOMs and 40% of C of biochar remained. Our data highlighted that in mixture, the presence of biochar led to about 40% higher amounts of C remaining, most probably related to aggregate formation preventing physical disintegration and/or leaching losses. Consequently, this study demonstrated the interest of mixing organic substrates with biochar for preventing C removal from soil immediately after field exposure. (C) 2016 Published by Elsevier B.V.
Published: 2016
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12. Influence of earthworms and termites on runoff and erosion in a tropical steep slope fallow in Vietnam: A rainfall simulation experiment

Author: Hai Tran Sy, Christian Valentin, Pascal Jouquet, Didier Orange, Luu Thi Nguyet Minh, Alexandro Pisano, and Jean-Louis Janeau
Subjects: Soil biodiversity, Soil Science, Soil science, complex mixtures, Soil retrogression and degradation, Soil ecology, DEGRADATION DU SOL, STABILITE STRUCTURALE, Ecosystem, Ecology, biology, SURFACE DU SOL, TERMITE, Earthworm, biology.organism_classification, Agricultural and Biological Sciences (miscellaneous), JACHERE, Agronomy, Soil water, HYDRODYNAMIQUE, Erosion, Environmental science, EROSION HYDRIQUE, SIMULATION DE PLUIE, Surface runoff, LOMBRIC
Abstract: Earthworms and termites, as soil engineers, play a major role in the regulation of biogeochemical processes and the provision of ecosystem services. They create biogenic aggregates on the soil surface, e.g., earthworm casts and termite sheetings, which can influence soil erosion and the downward transfer of fertility. We assessed the effect of the micro-relief generated by earthworms and termites on soil hydrodynamic properties, and soil and nutrient losses. Eighteen 1 m × 1 m plots were established for rainfall simulation experiments (2 runs of 40 min rain, intensity 90 mm h −1 ) in a steep slope fallow in Northern Vietnam. The soil surface of the micro-plots differed in the proportions of earthworm casts and termite sheetings. The results confirmed the importance of soil biostructures in the regulation of pedohydrological properties of soils. Although globular water-stable earthworm casts promote water infiltration in soil and decrease soil and nutrient losses, the unstable termite sheetings break-down rapidly and generate structural crusts which foster water runoff and soil detachment. No relation was observed between the abundance or biomass of earthworms or termites and the pedohydrological properties measured during the rainfall simulations. This therefore suggests that soil engineers can have greater impact on ecosystem functioning through their biogenic structures rather than as a result of their own abundance or biomass.
Published: 2012
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13. Impact of compost, vermicompost and biochar on soil fertility, maize yield and soil erosion in Northern Vietnam : a three year mesocosm experiment

Author: Pascal Jouquet, Cornelia Rumpel, Jean-Louis Janeau, Thuy Thu Doan, Thierry Henry-des-Tureaux, Institut d'écologie et des sciences de l'environnement de Paris (iEES), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Recherche Agronomique (INRA), Soils and Fertilizers Research Institute (SFRI), Vietnam Academy of Agricultural Sciences (VAAS), National Agriculture and Forestry Research Institute (NAFRI), International Joint Laboratory Indo-French Cell for Water Sciences (IFCWS), SysteMO project, BioGEAQ project, French institutes IRD (unit research UMR-242-iEES Paris), CNRS, French embassy, IRD, and Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Geological Phenomena, Environmental Engineering, [SDV]Life Sciences [q-bio], engineering.material, Zea mays, Civil Engineering, Soil, Biochar, Animals, Environmental Chemistry, Biomass, Oligochaeta, Fertilizers, Waste Management and Disposal, Ecosystem, 2. Zero hunger, Acrisol, Compost, Crop yield, Agriculture, Plants, 15. Life on land, Pollution, Soil quality, Manure, Mesocosms, Ecological engineering, Fertility, Water quality, Vietnam, Agronomy, Charcoal, engineering, Environmental science, Soil fertility, Tropical soil, Vermicompost
Abstract: Compost, vermicompost and biochar amendments are thought to improve soil quality and plant yield. However, little is known about their long-term impact on crop yield and the environment in tropical agro-ecosystems. In this study we investigated the effect of organic amendments (buffalo manure, compost and verrnicompost) and biochar (applied alone or with vermicompost) on plant yield, soil fertility, soil erosion and water dynamics in a degraded Acrisol in Vietnam. Maize growth and yield, as well as weed growth, were examined for three years in terrestrial mesocosms under natural rainfall. Maize yield and growth showed high inter-annual variability depending on the organic amendment. Vermicompost improved maize growth and yield but its effect was rather small and was only significant when water availability was limited (year 2). This suggests that vermicompost could be a promising substrate for improving the resistance of agrosystems to water stress. When the vermicompost biochar mixture was applied, further growth and yield improvements were recorded in some cases. When applied alone, biochar had a positive influence on maize yield and growth, thus confirming its interest for improving long-term soil productivity. All organic amendments reduced water runoff, soil detachment and NH4+ and NO3- transfer to water. These effects were more significant with vermicompost than with buffalo manure and compost, highlighting that the beneficial influence of vermicompost is not limited to its influence on plant yield. In addition, this study showed for the first time that the combination of vermicompost and biochar may not only improve plant productivity but also reduce the negative impact of agriculture on water quality. (C) 2015 Elsevier B.V. All rights reserved.
Published: 2015
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14. Water and health: what is the risk and visible burden of the exposure to environmental contaminations? Insights from a questionnaire-based survey in Northern Thailand

Author: Wasana Khaungaew, Kraichat Tantrakarnapa, Jean-Louis Janeau, Vincent Herbreteau, UMR 228 Espace-Dev, Espace pour le développement, Université des Antilles (UA)-Université de Guyane (UG)-Université de Montpellier (UM)-Université de La Réunion (UR)-Avignon Université (AU)-Université de Perpignan Via Domitia (UPVD)-Institut de Recherche pour le Développement (IRD), Phrae provincial Public Health Office, Ministry of Public Health - Thailande, Institut de Recherche pour le Développement (IRD), Biogéochimie et écologie des milieux continentaux (Bioemco), Centre National de la Recherche Scientifique (CNRS)-AgroParisTech-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Recherche Agronomique (INRA)-École normale supérieure - Paris (ENS Paris), Géosciences Environnement Toulouse (GET), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Serge Morand, Jean-Pierre Dujardin, Régine Lefait-Robin, Chamnarn Apiwathnasorn, Université de Guyane (UG)-Université des Antilles (UA)-Institut de Recherche pour le Développement (IRD)-Université de Perpignan Via Domitia (UPVD)-Avignon Université (AU)-Université de La Réunion (UR)-Université de Montpellier (UM), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Institut de Recherche pour le Développement (IRD)-Université de Perpignan Via Domitia (UPVD)-Avignon Université (AU)-Université de La Réunion (UR)-Université de Montpellier (UM)-Université de Guyane (UG)-Université des Antilles (UA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Morand, S. (ed.), Dujardin, Jean-Pierre (ed.), Lefait-Robin, R. (ed.), and Apiwathnasorn, C. (ed.)
Subjects: medicine.medical_specialty, Inequality, Environmental contamination, media_common.quotation_subject, Context (language use), Environmental pollution, 010501 environmental sciences, 01 natural sciences, 03 medical and health sciences, 0302 clinical medicine, Environmental health, Epidemiology, Northern Thailand, medicine, 030212 general & internal medicine, Environmental planning, 0105 earth and related environmental sciences, media_common, Downstream (petroleum industry), 2. Zero hunger, business.industry, Public health, Water, [SHS.GEO]Humanities and Social Sciences/Geography, 15. Life on land, Risk exposure, [SDE.ES]Environmental Sciences/Environmental and Society, 6. Clean water, 3. Good health, Incentive, Geography, 13. Climate action, Agriculture, Health, [SDV.SPEE]Life Sciences [q-bio]/Santé publique et épidémiologie, business
Abstract: International audience; Understanding and measuring the consequences of environmental pollution on human health remains a challenge. Several barriers arise, with the difficulty in identifying uncommon pathologies but also with the limited knowledge of the real health status of populations that depends on the supply and use of care. In an effort to assess these barriers, we chose a study area severely affected by agricultural intensification to investigate the potential and visible impact of water pollution on human health. Located in northern Thailand, the study area includes a watershed, its reservoir and the irrigated area downstream. A questionnaire-based survey was conducted to assess the exposure of 297 households to potential water pollutions and understand their behaviour regarding the use of water and recourse to health services. The observations are discussed in the light of the epidemiological records provided by the Ministry of Public Health for the same area. The study shows the heterogeneity of the epidemiological data and the difficulty to assess the sanitary risk. Despite the small size of the study area, inequalities are observed, with remote populations having a poorer access to water with occasional shortage and a limited use of health services. In this context, the intensification of agriculture and the massive use of pesticides and fertilizers are likely to have serious consequences on human health. However, the impact of potential environmental pollution is not visible from the epidemiological records, because of a difficult diagnosis, a lack of consultation when symptoms are reversible and the long latency before clinical symptoms are apparent (example of cancers). Prevention and incentive from health authorities should help in reducing this risk.
Published: 2015

15. Off-site impacts of agricultural composting: role of terrestrially derived organic matter in structuring aquatic microbial communities and their metabolic potential

Author: Patrice Got, Thomas Pommier, Tran Duc Toan, Jean-Louis Janeau, Asmaa Merroune, Pascal Jouquet, Thuy Doan Thu, Yvan Bettarel, Emma Rochelle-Newall, Laboratoire d'Ecologie Microbienne - UMR 5557 (LEM), Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Vétérinaire de Lyon (ENVL)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de la Recherche Agronomique (INRA)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS), Institut National de la Recherche Agronomique (INRA)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Ecole Nationale Vétérinaire de Lyon (ENVL), French EC2CO programme 'COMPAQUA', Institut de Recherche pour le Developpement, UMR laboratory iEES, UMR laboratory EM, PHC Hoa Sen Lotus [23970QM], and LOTUS, MOST [44/2012/HD-NDT]
Subjects: Aquatic Organisms, SOL CULTIVE, [SDV]Life Sciences [q-bio], BACTERIE, DIVERSITE SPECIFIQUE, STRUCTURE DE POPULATION, Applied Microbiology and Biotechnology, Soil leachates, Soil, Off-site effects, Dissolved organic carbon, Biochar, LESSIVAGE, MATIERE ORGANIQUE DISSOUTE, Organic Chemicals, COMPOST, Soil Microbiology, chemistry.chemical_classification, VERMICOMPOST, Ecology, Compost, Aquatic ecosystem, Community structure, Agriculture, METABOLISME, Charcoal, Viruses, VIRUS, CONSEQUENCE ECOLOGIQUE, Microbial Consortia, engineering.material, Biology, Microbiology, Civil Engineering, complex mixtures, ABONDANCE, Organic matter, 14. Life underwater, Fertilizers, LAC, BIOCHAR, Bacteria, MICROORGANISME, 15. Life on land, CARBONE ORGANIQUE, Lakes, chemistry, Metabolic potential, 13. Climate action, engineering, EROSION HYDRIQUE, Species richness, Vermicompost
Abstract: International audience; While considered as sustainable and low-cost agricultural amendments, the impacts of organic fertilizers on downstream aquatic microbial communities remain poorly documented. We investigated the quantity and quality of the dissolved organic matter leaching from agricultural soil amended with compost, vermicompost or biochar and assessed their effects on lake microbial communities, in terms of viral and bacterial abundances, community structure and metabolic potential. The addition of compost and vermicompost significantly increased the amount of dissolved organic carbon in the leachate compared to soil alone. Leachates from these additions, either with or without biochar were highly bioavailable to aquatic microbial communities, though reducing the metabolic potential of the community and harboring more specific communities. Although not affecting bacterial richness or taxonomic distributions, the specific addition of biochar affected the original lake bacterial communities resulting in a strongly different community. This could be partly explained by viral burst and converging bacterial abundances throughout the samples. These results underline the necessity to include off-site impacts of agricultural amendments when considering their cascading effect on downstream aquatic ecosystems. This article is protected by copyright. All rights reserved.
Published: 2014
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16. CDOM fluorescence as a proxy of DOC concentration in natural waters: a comparison of four contrasting tropical systems

Author: Jean-Louis Janeau, Emma Rochelle-Newall, Asmaa Merroune, Florence D. Hulot, Institut d'Ecologie et des Sciences de l'Environnement de Paris, Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Recherche pour le Développement (IRD [France-Ouest])-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Ecole Normale Supérieure Paris-Saclay (ENS Paris Saclay), Ecologie Systématique et Evolution (ESE), Université Paris-Sud - Paris 11 (UP11)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS), Soils and Fertilizers Research Institute (SFRI), Vietnam Academy of Agricultural Sciences (VAAS), French IRD, UMR Bioemco, French program EC2CO-Haiphong, French program EC2CO-Compaqua, French program CNES/TOSCA-VITEL, ANR Vulnerabilite-INTERFACE, and ANR Biodiversite-BIOFUN
Subjects: [SDE.MCG]Environmental Sciences/Global Changes, Fluorometer, Fresh Water, Management, Monitoring, Policy and Law, Fluorescence, Chromophoric dissolved organic matter, Tropical climate, Dissolved organic carbon, Ecotoxicology, Ecosystem, Leachate, General Environmental Science, Tropical Climate, geography, geography.geographical_feature_category, Estuary, General Medicine, Pollution, [SDE.ES]Environmental Sciences/Environmental and Society, Carbon, 6. Clean water, Colored dissolved organic matter, Environmental chemistry, Environmental science, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Water Pollutants, Chemical, Environmental Monitoring
Abstract: A table in this article is not correct. See: http://prodinra.inra.fr/record/259698 to retrieve the right table.; International audience; Chromophoric dissolved organic matter (CDOM) fluorescence or absorption is often proposed as a rapid alternative to chemical methods for the estimation of bulk dissolved organic carbon (DOC) concentration in natural waters. However, the robustness of this method across a wide range of systems remains to be shown. We measured CDOM fluorescence and DOC concentration in four tropical freshwater and coastal environments (estuary and coastal, tropical shallow lakes, water from the freshwater lens of two small islands, and soil leachates). We found that although this method can provide an estimation of DOC concentration in sites with low variability in DOC and CDOM sources in systems where the variability of DOC and CDOM sources are high, this method should not be used as it will lead to errors in the estimation of the bulk DOC concentration.
Published: 2014
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17. Influence of buffalo manure, compost, vermicompost and biochar amendments on bacterial and viral communities in soil and adjacent aquatic systems

Author: Thuy Thu Doan, Corinne Bouvier, Patrice Lamballe, Thierry Bouvier, Jean-Louis Janeau, Bo Van Nguyen, Pascal Jouquet, Thierry Henry-des-Tureaux, and Yvan Bettarel
Subjects: ECOSYSTEME, Amendment, Soil Science, BACTERIE, engineering.material, complex mixtures, ABONDANCE, RUISSELLEMENT, PROPRIETE CHIMIQUE, AMENDEMENT DU SOL, Biochar, ETUDE COMPARATIVE, Organic matter, COMPOST, ANALYSE STATISTIQUE, chemistry.chemical_classification, BIOCHAR, Ecology, VERMICOMPOST, Compost, fungi, MATIERE ORGANIQUE, Agricultural and Biological Sciences (miscellaneous), Manure, MAIS, Agronomy, chemistry, INFILTRATION, EAU, ELECTROPHORESE, FERTILISATION DU SOL, engineering, VIRUS, ETUDE EXPERIMENTALE, Fertilizer, Surface runoff, Vermicompost, FUMIER
Abstract: Vermicompost and biochar amendments are management practices which may contribute to sustainable agroecosystems by reducing dependence on inorganic fertilizers. However, little is known about their impacts on soil microorganisms and their transfer and evolution in connected aquatic systems. The aim of this study was to determine the influence of organic manure (buffalo manure, compost or vermicompost) and biochar amendments on bacterial and viral properties in soil and water. A three year experiment was carried out with terrestrial mesocosms which were used to test the effect of organic matter amendment on maize growth. In the last year of the experiment, runoff and infiltration waters from the terrestrial mesocosms were transferred to aquatic mesocosms. Organic fertilization improved soil properties (higher C, N content and pH H 2 O ) and as a consequence increased soil bacterial and viral abundance. Bacterial diversity (Shannon ‘H’ and richness ‘S’ indices calculated from DGGE fingerprint) was also enhanced after the continuous application of organic amendments. Compared with compost, vermicompost reduced viral abundance and S but similar H and bacterial abundance were observed. The pH H 2 O , C content and bacterial and viral abundance increased in the aquatic mesocosms following organic fertilization. As a consequence, bacterial and viral diversity also increased in the water, although no differences were found between compost and vermicompost. Biochar increased soil bacterial abundance for the mineral fertilizer treatment but did not influence bacterial and viral abundance in water. However, the combination of biochar and vermicompost led to an increase of viruses in soil and a reduction of bacteria in water. Similarity dendrograms from the DGGE banding patterns showed that the structure of bacterial communities was mainly influenced by the fertilizer treatments in soil but by the presence of biochar in water. In conclusion, this study demonstrated that the nature of the organic amendment has important consequences on both soil and water microbial abundance and diversity.
Published: 2014

18. Soil erosion, dissolved organic carbon and nutrient losses under different land use systems in a small catchment in northern Vietnam

Author: Hai Tran Sy, Thi Phuong Quynh Le, Pascal Jouquet, Dinh Rinh Pham, Quoc Anh Ngo, Séraphine Grellier, Thi Nguyet Minh Luu, Lc Gillard, Emma Rochelle Newall, Trinh Anh Duc, Christian Valentin, Jean-Louis Janeau, Duc Toan Tran, Didier Orange, Biogéochimie et écologie des milieux continentaux (Bioemco), Centre National de la Recherche Scientifique (CNRS)-AgroParisTech-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Recherche Agronomique (INRA)-École normale supérieure - Paris (ENS Paris), WEO Department, University of sciences and technologies of hanoi (USTH), Université Pierre et Marie Curie - Paris 6 (UPMC), Vietnam Academy of Science and Technology (VAST), A18-Institute of Chemistry, Vietnamese Academy of Science and Technology, Ecologie des systèmes marins côtiers (Ecosym), Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS), Soils and Fertilizers Research Institute (SFRI), Vietnam Academy of Agricultural Sciences (VAAS), Veolia Environnement Recherche et Innovation, Veolia, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Institut d'écologie et des sciences de l'environnement de Paris (iEES Paris), Institut National de la Recherche Agronomique (INRA)-Sorbonne Université (SU)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Biomécanique et Mécanique des Chocs (LBMC UMR T9406), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR), Institut d'écologie et des sciences de l'environnement de Paris (iEES), Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), UR 103 Camélia, Institut de Recherche pour le Développement (IRD), French Institut de Recherche pour le Developpement (IRD), UMR BIOEMCO, project PAMPA, PHC Hoa Sen Lotus [23970QM], LOTUS [44/2012/HD-NDT], MOST, Vietnam, Institut d'écologie et des sciences de l'environnement de Paris (IEES (UMR_7618 / UMR_D_242 / UMR_A_1392 / UM_113) ), Institut d'écologie et des sciences de l'environnement de Paris (IEES), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Recherche Agronomique (INRA), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS), and University of Science and Technology of Hanoi (USTH)
Subjects: FORET, 010504 meteorology & atmospheric sciences, SOL CULTIVE, 01 natural sciences, Agricultural land, Dissolved organic carbon, PERTE EN TERRE, Tropical catchments, DEGRADATION DU SOL, MATIERE ORGANIQUE DISSOUTE, ComputingMilieux_MISCELLANEOUS, Water Science and Technology, 2. Zero hunger, Agroforestry, Aquatic ecosystem, 04 agricultural and veterinary sciences, No-till, Plant litter, CARBONE, PRATIQUE CULTURALE, BASSIN VERSANT, Erosion, [SDE]Environmental Sciences, PENTE, SIMULATION DE PLUIE, COUVERT VEGETAL, Soil Science, TRAVAIL DU SOL, No-till farming, ALTITUDE, AZOTE, ETUDE COMPARATIVE, Ecosystem, Soil carbon loss, 14. Life underwater, 0105 earth and related environmental sciences, Earth-Surface Processes, Rain simulations, PHOSPHORE, Soil carbon, 15. Life on land, NUTRIMENT, JACHERE, Agronomy, MULCH, Acacia mangium, [SHS.ENVIR]Humanities and Social Sciences/Environmental studies, Soil water, 040103 agronomy & agriculture, 0401 agriculture, forestry, and fisheries, Environmental science, EROSION HYDRIQUE, Agronomy and Crop Science, ZONE DE MONTAGNE
Abstract: International audience; The export of dissolved organic carbon (DOC) from agricultural soils can represent an important pathway of soil organic carbon loss. However, despite its importance in terrestrial and downstream aquatic ecosystems, most work has focused on temperate agrosystems with tropical and sub-tropical ecosystems being ignored. Here we present the results of a series of rain simulation experiments aimed at examining DOC export from sloping lands in North Vietnam. Three regularly used agricultural practices were tested and compared with Bare soils. We also compared the impact of leaf litter in two planted forest sites. We found high rates of DOC export (0.03-0.25 g C m(-2)) during a 40 min rain episode with the lowest rates observed in the Bare soils and the highest in the planted Forest without leaf litter. This is equivalent to a loss of between 0.001 and 0.008% of the total soil organic carbon in the upper 10 cm during a single, intense rain event. This work highlights the impact of different agricultural practices (Bare soil, hoeing, mulching and fallow) and land use (planted Forest with or without leaf litter) on the export of DOC from upland, tropical soils and further underlines the importance of studying DOC fluxes from agricultural land as it represents an important and highly mobile component of ecosystem carbon fluxes.
Published: 2014
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19. Positive versus negative environmental impacts of tree encroachment in South Africa

Author: Séraphine Grellier, Simon Lorentz, Luc Abbadie, Pascal Podwojewski, David Ward, Sébastien Barot, Jean-Louis Janeau, Christian Valentin, WEO Department, University of sciences and technologies of hanoi (USTH), University of KwaZulu-Natal (UKZN), Biogéochimie et écologie des milieux continentaux (Bioemco), Centre National de la Recherche Scientifique (CNRS)-AgroParisTech-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Recherche Agronomique (INRA)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), University of Science and Technology of Hanoi (USTH), University of KwaZulu-Natal [Durban, Afrique du Sud] (UKZN), École normale supérieure - Paris (ENS-PSL), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, INVASION, Acacia, DIVERSITE SPECIFIQUE, SAVANE, QUALITE, 010603 evolutionary biology, 01 natural sciences, Grassland, AZOTE, COMPETITION INTERSPECIFIQUE, PROPRIETE PHYSICOCHIMIQUE, DYNAMIQUE DE VEGETATION, Magnesium ion, Ecology, Evolution, Behavior and Systematics, Nature and Landscape Conservation, 2. Zero hunger, Biomass (ecology), geography, geography.geographical_feature_category, BIOMASSE, biology, SOL, Ecology, Agroforestry, STRATE HERBACEE, PATURAGE, Acacia sieberiana, ARBUSTE, PLANTE FOURRAGERE, 04 agricultural and veterinary sciences, Soil carbon, 15. Life on land, Herbaceous plant, biology.organism_classification, CARBONE, Agronomy, 13. Climate action, [SDE]Environmental Sciences, 040103 agronomy & agriculture, 0401 agriculture, forestry, and fisheries, HERBACEE, ZONE DE MONTAGNE, Woody plant, IMPACT SUR L'ENVIRONNEMENT
Abstract: International audience; Woody plant encroachment in grasslands is a worldwide phenomenon. Despite many studies, the consequences of woody plant encroachment on sub-canopy vegetation and soil properties are still unclear. To better understand the impacts of trees on grassland properties we examined the following questions using a mountainous sub-tropical grassland of South Africa encroached by an indigenous tree, Acacia sieberiana as a case study: (1) Do trees increase sub-canopy herbaceous diversity, quality and biomass and soil nitrogen content? (2) Do large trees have a stronger effect than medium-sized trees on grass and soil properties? (3) Does the impact of trees change with the presence of livestock and position of trees in a catena? We studied grass and non-graminoid species diversity and biomass, grass quality and soil properties during the wet season of 2009. Nitrogen in grass leaves, soil cation exchange capacity and calcium and magnesium ion concentrations in the soil increased under tall Acacia versus open areas. Medium-sized Acacia decreased the gross energy content, digestibility and neutral detergent fibre of grasses but increased the species richness of non-graminoids. Tall and medium Acacia trees were associated with the presence of Senecio inaequidens, an indigenous species that is toxic to horses and cattle. The presence of livestock resulted in a decrease in herbaceous root biomass and an increase in soil carbon and leaf biomass of grass under Acacia. Tree position in the catena did not modify the impact of trees on the herbaceous layer and soil properties. For management of livestock we recommend retaining tall Acacia trees and partially removing medium-sized Acacia trees because the latter had negative effects on grass quality.
Published: 2013
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20. Grass competition is more important than seed ingestion by livestock for Acacia recruitment in South Africa

Author: Sébastien Barot, David Ward, Séraphine Grellier, Jean-Louis Janeau, and IRD-BIOEMCO c/o School of Bioresources Engineering and Environmental Hydrology (BEEH), Rabie Saunders Building, University of KwaZulu-Natal, Box X01, Scottsville 3209, South Africa
Subjects: 0106 biological sciences, media_common.quotation_subject, Acacia, Plant Science, SAVANE, 010603 evolutionary biology, 01 natural sciences, Competition (biology), ARBRE, parasitic diseases, Grazing, COMPETITION INTERSPECIFIQUE, ComputingMilieux_MISCELLANEOUS, media_common, LEGUMINEUSE TROPICALE, 2. Zero hunger, Herbivore, Ecology, biology, PATURAGE, food and beverages, Acacia sieberiana, 04 agricultural and veterinary sciences, Interspecific competition, 15. Life on land, biology.organism_classification, Plant ecology, Agronomy, BETAIL, 040103 agronomy & agriculture, 0401 agriculture, forestry, and fisheries, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, FEU DE BROUSSE, GERMINATION, Woody plant
Abstract: Although grazing livestock may have direct negative effects on woody species through herbivory and trampling, (heavy-)grazing is often associated with woody plant encroachment. Two main mechanisms can explain the positive effects of grazers on woody cover: (1) Grazers reduce the interspecific competition with trees and may reduce fuel load, and (2) gut passage through livestock increases seedling establishment by scarification (increased germination) and fertilization by dung (higher survival and growth of seedlings). We tested the effects of fire, grass, cattle ingestion (transit) and dung on germination, seedling height and survival as well as on recruitment of Acacia sieberiana in a sub-humid grassland of South Africa. About 8,000 seeds were planted in the field in a randomized block design. The removal of grass by grazing and/or fire had the most important effect on Acacia recruitment in savanna. Our findings highlight the hierarchy of the main factors affecting Acacia recruitment, which provides new insights to the understanding of woody plant encroachment.
Published: 2012
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21. The indirect impact of encroaching trees on gully extension : a 64 year study in a sub-humid grassland of South Africa

Author: Séraphine Grellier, Jaco Kemp, Christian Valentin, Pascal Podwojewski, Sébastien Barot, Jean-Louis Janeau, Nicolas Florsch, Simon Lorentz, David Ward, and IRD-BIOEMCO c/o School of Bioresources Engineering and Environmental Hydrology (BEEH), Rabie Saunders Building, University of KwaZulu-Natal, Box X01, Scottsville 3209, South Africa
Subjects: Canopy, 010504 meteorology & atmospheric sciences, COUVERT VEGETAL, DRAINAGE, [SDE.MCG]Environmental Sciences/Global Changes, Drainage basin, Acacia, SAVANE, 01 natural sciences, Grassland, RUISSELLEMENT, ARBRE, Drainage, Subsurface flow, PHOTOGRAPHIE AERIENNE, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Earth-Surface Processes, Hydrology, geography, geography.geographical_feature_category, biology, 04 agricultural and veterinary sciences, 15. Life on land, biology.organism_classification, BASSIN VERSANT, PRAIRIE, INFILTRATION, PLUIE, 040103 agronomy & agriculture, Erosion, 0401 agriculture, forestry, and fisheries, Environmental science, RAVINEMENT, EROSION HYDRIQUE, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, VARIATION PLURIANNUELLE, Woody plant
Abstract: Gully erosion and woody plant encroachment are frequently observed in grasslands worldwide. Gully erosion driven by water processes is usually affected by topography, land-use change and vegetation cover. We hypothesised that trees, through their potential link with overland and subsurface flow, may have an impact on gully extension. However, very few studies have simultaneously considered tree encroachment and gullies. We used aerial photographs to study Acacia sieberiana encroachment and gully erosion in a South African grassland (KwaZulu-Natal Province) for a period lasting 64 years. At the catchment scale, results showed that acacias started invading after 1976 and transformed the grassland into a savanna with 9.45% of tree cover in 2009. Gully area increased by 3.9% in the last 64 years and represented 12.76% of catchment area in 2009. Mean estimated sediment loss was 200 Mg ha− 1 of gully y− 1, indicating a high erosion rate mainly due to the collapse of gully banks after swelling and shrinking. Volumetric retreat rate (V) of 15 gully heads was correlated with drainage area (Drain.A) by a power function explaining 64% of the variance: V = 0.02*Drain.A0.83. A positive correlation between gully retreat rate and Acacia canopy area was measured between 2001 and 2009 when established tree encroachment was observed. These results, associated with the susceptibility of this soil to subsurface flow and the observation of pipe erosion systems in the field, showed that both surface and subsurface processes occur in this sub-humid grassland and that trees can be indirectly associated with increased gully erosion.
Published: 2012
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22. Impact of land use change and rainfall on sediment and carbon accumulation in a water reservoir of North Thailand

Author: Warinya Thothong, Arthorn Boonsaner, Anneke de Rouw, Olivier Planchon, Gérard Bardoux, Sylvain Huon, Preeda Parkpian, Jean-Louis Janeau, Biogéochimie et écologie des milieux continentaux (Bioemco), Centre National de la Recherche Scientifique (CNRS)-AgroParisTech-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Recherche Agronomique (INRA)-École normale supérieure - Paris (ENS Paris), Institut de Recherche pour le Developpement (IRD), Kasetsart University, national park wildlife and plant convervation department (NPWPCD), NPWPCD, Asian Institute of Technology [Pathumthani] (AIT), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS), Kasetsart University (KU), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)
Subjects: Watershed, 010504 meteorology & atmospheric sciences, 010501 environmental sciences, 01 natural sciences, Stable carbon isotopes, Organic matter, Deforestation, Lake organic matter, 0105 earth and related environmental sciences, Total organic carbon, Hydrology, chemistry.chemical_classification, Suspended sediments, Ecology, • Lake organic matter, Soil organic matter, Sediment, 15. Life on land, • Soil erosion, 6. Clean water, Siltation, Tropical reservoir, chemistry, 13. Climate action, Annual crops, [SDE]Environmental Sciences, Erosion, Soil erosion, Environmental science, Animal Science and Zoology, Surface runoff, Agronomy and Crop Science
Abstract: The lifespan of many tropical water reservoirs is limited by siltation due to soil erosion in the watershed. The objectives of this study were to determine, the amount of catchment-derived organic carbon accumulated in sediments of a reservoir of North Thailand and to relate it with the history of cultivation and rainfall regime in the watershed. Over a twelve-years period (1995-2006) since impoundment sediment delivery was high (ca. 19.6 Mg ha(-1) yr(-1)). The yearly supply of catchment-derived material was composed of coarse sediment deposits near the main inlets and of fine laminated sediment accumulations in deep-water environments. Their stable carbon isotope composition indicated that soil organic matter was the main source of organic carbon preserved in sediments (ca. 83 wt.%). Fine sediments derived from suspended loads exported from the watershed by runoff and stream waters were related to erosive rainfall, to the extent of area under annual cropping and to crop change with a marked increase after the replacement of beans by maize. However, sediment accumulation did not respond linearly to extreme rainfall events, as shown by the supply of nearly 48% of the total amount of sediments by a single exceptional flood. Total organic carbon storage in sediments reached ca. 23.8 MgC ha(-1) yr(-1) in 2006, twelve years after impoundment, falling in the upper range of small to medium size reservoirs with agricultural catchments.
Published: 2011
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23. Rainfall simulation to identify the storm-scale mechanisms of gully bank retreat

Author: Jean-Louis Janeau, Cornelia Rumpel, Pascal Podwojewski, Jacqueline Brown, Lauren Martin, Vincent Chaplot, Charmaine Nontokozo-Mchunu, Phesheya Dlamini, Ernest Oakes, Graham Jewitt, Simon Lorentz, Nhlakanipho Zondi, Sylvain Revil, Tarryn Eustice, Institut de Recherche pour le Développement (IRD [Réunion]), University of KwaZulu-Natal (UKZN), University of Pretoria [South Africa], South African Sugarcane Research Institute, KwaZulu-Natal Department of Agriculture and Environmental Affairs, Biogéochimie et écologie des milieux continentaux (Bioemco), Centre National de la Recherche Scientifique (CNRS)-AgroParisTech-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Recherche Agronomique (INRA)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Netherlands Foundation for the Advancement of Tropical Research (WOTRO), Swedish International Development Cooperation Agency (Sida), Netherlands Directorate-General of Development Cooperation (DGIS), International Water Management Institute (IWMI), UNESCO-IHE Institute for Water Education, Departement Soutien Formation (DSF) of the Institut de Recherche pour le Developpement (IRD, former ORSTOM), School of Bioresources Engineering and Environmental Hydrology, Rabie Saunders Building, University of Kwazulu-Natal, University of KwaZulu-Natal [Durban, Afrique du Sud] (UKZN), École normale supérieure - Paris (ENS-PSL), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS)
Subjects: Bank retreat, Watershed, 010504 meteorology & atmospheric sciences, Erosion control, [SDV]Life Sciences [q-bio], Soil Science, INTERRILL EROSION, 01 natural sciences, CHINA, South Africa, NORTHERN LAOS, Gully erosion, SLOPING LANDS, ERODIBILITY, RATES, Bank erosion, 0105 earth and related environmental sciences, Earth-Surface Processes, Water Science and Technology, Hydrology, Splash, Involved mechanisms, Storm, 04 agricultural and veterinary sciences, 15. Life on land, SOUTH-AFRICA, Bulk density, SOIL, MODEL, [SDE]Environmental Sciences, 040103 agronomy & agriculture, Erosion, 0401 agriculture, forestry, and fisheries, Environmental science, Surface runoff, Agronomy and Crop Science
Abstract: International audience; Gully erosion is one of the main causes of soil loss in drylands. Understanding the dominant mechanisms of erosion is important to achieve effective erosion control, thus in this study our main objective was to quantify the mechanisms involved in gully bank retreat as a result of three processes, falling of entire soil aggregates, transport of soil material by splash and by water running along gully banks (runoff). during rainfall events. The study was conducted in the sloping lands of the KwaZulu-Natal province, a region that is highly affected by gully erosion. Artificial rain was applied at 60 mm h(-1) for 45 min at the vertical wall of a gully bank typical to the area. The splash material was collected by using a network of 0.045 m(2) buckets. The sediments in the running water were assessed by sampling the runoff collected from a microplot inserted within the base of the bank, and collecting the fallen aggregates after the rainfall simulation was complete. Results indicated that the overall erosion for the simulation was 721 g m(-2) h(-1). Runoff erosion proved to be the dominant mechanism and amounted to 450g m(-2) h(-1), followed by splash and fall down of aggregates (about 170 g m(-2) h(-1)). Gully bank retreat occurred at a rate of 0.55 mm h(-1) and assuming that the soil bulk density is 1.3 g cm(-3), this corresponds to a retreat of 8.8 mm y(-1). Extrapolations to the watershed level, where about 500 m(2) of gully bank are observed per hectare, would lead to an erosion rate of 4.8 t ha(-1) y(-1). These limited results based on a simulated storm show that the three main mechanisms (runoff, splash and fall down of aggregates) are responsible for the retreat of gully banks and that to mitigate gully erosion, appropriate measures are required to control all three mechanisms. Further research studies are needed to confirm and to scale up, both in time and space, as these data are obtained at one location and from a single artificial storm. (C) 2010 Elsevier B.V. All rights reserved.
Published: 2011
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24. Water funnelling by the crown of Flourensia cernua, a Chihuahuan Desert shrub

Author: Jean-Louis Janeau and A. Mauchamp
Subjects: Stemflow, COUVERT VEGETAL, ved/biology.organism_classification_rank.species, EAU DU SOL, ALIMENTATION EN EAU, PLANTE, DESERT, Shrub, PRODUCTION VEGETALE, ABSORPTION, MESURE, ECOULEMENT, Ecology, Evolution, Behavior and Systematics, RELATION SOL EAU PLANTE, Earth-Surface Processes, Hydrology, BIOMASSE, Ecology, biology, ved/biology, TIGE, HUMIDITE DU SOL, ETUDE D'IMPACT, Flourensia cernua, ARBUSTE, Throughfall, biology.organism_classification, Infiltration (hydrology), INFILTRATION, Soil water, Environmental science, SIMULATION DE PLUIE, Interception, Surface runoff, FEUILLE
Abstract: In arid climates, plant growth and survival depend primarily upon the amount of soil water available at the roots. Variation in soil water content at the individual plant level must then be taken into account to analyse the production and dynamics of vegetation cover. The plant itself modifies local water availability through rainfall interception and stemflow. Rainfall interception and stemflow was studied for a shrub, Flourensia cernua, a dominant species of vegetation stripes in the Chihuahuan Desert, Mexico, in order to determine to what extent it could influence soil water recharge. Simulated rainfalls were applied at two intensifies on six 1 m2 plots centered around each shrub. Shrub cover was determined from vertical photographs. Experimental clipping from three shrubs allowed observations on the decrease in stemflow according to cover and measurement of the dry biomass of leaves and twigs. An experimental design enabled measurements to be made on throughfall, runoff from the base of the shrub, and to deduce stemflow and infiltration. Stemflow accounted for 4-45 per cent of the rainfall in our study plots and was significantly correlated with shrub cover. It was higher for the lower rainfall intensity. Stemflow, together with a high soil permeability, resulted in a greater soil water recharge under the shrub.
Published: 1993
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25. Influence of grass soil cover on water runoff and soil detachment under rainfall simulation in a sub-humid South African degraded rangeland

Author: Séraphine Grellier, Jean-Louis Janeau, Pascal Podwojewski, Christian Valentin, Simon Lorentz, Vincent Chaplot, Biogéochimie et écologie des milieux continentaux (Bioemco), Centre National de la Recherche Scientifique (CNRS)-AgroParisTech-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Recherche Agronomique (INRA)-École normale supérieure - Paris (ENS Paris), University of KwaZulu-Natal (UKZN), School of Bioresources Engineering and Environmental Hydrology University of KwaZulu-Natal, PB X01, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS), and University of KwaZulu-Natal [Durban, Afrique du Sud] (UKZN)
Subjects: 010504 meteorology & atmospheric sciences, Geography, Planning and Development, interrill erosion, runoff, infiltration, 01 natural sciences, soil degradation, Soil retrogression and degradation, Earth and Planetary Sciences (miscellaneous), Overgrazing, 0105 earth and related environmental sciences, Earth-Surface Processes, 2. Zero hunger, Hydrology, 04 agricultural and veterinary sciences, rainfall simulation, 15. Life on land, Infiltration (hydrology), [SDE]Environmental Sciences, 040103 agronomy & agriculture, Land degradation, Erosion, 0401 agriculture, forestry, and fisheries, Soil horizon, Environmental science, Rangeland, soil cover, Surface runoff
Abstract: In most regions of the world overgrazing plays a major role in land degradation and thus creates a major threat to natural ecosystems. Several feedbacks exist between overgrazing, vegetation, soil infiltration by water and soil erosion that need to be better understood. In this study of a sub-humid overgrazed rangeland in South Africa, the main objective was to evaluate the impact of grass cover on soil infiltration by water and soil detachment. Artificial rains of 30 and 60 mm h−1 were applied for 30 min on 1 m2 micro-plots showing similar sandy-loam Acrisols with different proportions of soil surface coverage by grass (Class A: 75–100%; B: 75–50%; C: 50–25%; D: 25–5%; E: 5–0% with an outcropping A horizon; F: 0% with an outcropping B horizon) to evaluate pre-runoff rainfall (Pr), steady state water infiltration (I), sediment concentration (SC) and soil losses (SL). Whatever the class of vegetal cover and the rainfall intensity, with the exception of two plots probably affected by biological activity, I decreased regularly to a steady rate
Published: 2010
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26. Dung beetles (Coleoptera: Scarabaeidae) can improve soil hydrological properties

Author: Clarke H. Scholtz, Séraphine Grellier, Jacqueline Brown, Jean-Louis Janeau, Pascal Podwojewski, DEPARTMENT OF ZOOLOGY AND ENTOMOLOGY, University of Pretoria [South Africa], Biogéochimie et écologie des milieux continentaux (Bioemco), Centre National de la Recherche Scientifique (CNRS)-AgroParisTech-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Recherche Agronomique (INRA)-École normale supérieure - Paris (ENS Paris), School of Bioresources Engineering and Environmental Hydrology University of KwaZulu-Natal, PB X01, Department of Zoology and Entomology [Pretoria], École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)
Subjects: 0106 biological sciences, Runoff, Soil biology, Soil Science, 010603 evolutionary biology, 01 natural sciences, Paracoprid, Animal science, Water content, 2. Zero hunger, Scarabaeidae, Ecology, biology, Moisture, Infiltration, 04 agricultural and veterinary sciences, 15. Life on land, biology.organism_classification, beetles, Agricultural and Biological Sciences (miscellaneous), Bulk density, Infiltration (hydrology), Erosion, Soil water, [SDE]Environmental Sciences, 040103 agronomy & agriculture, 0401 agriculture, forestry, and fisheries, Environmental science, Land degradation, Surface runoff
Abstract: Although dung beetles are known to perform a multitude of ecosystem services, their effects on water infiltration, runoff, porosity, moisture and erosion of soil have never been thoroughly researched. Maintenance of these hydrological properties is important in agro-ecosystem functioning where overgrazing results in negative impacts on the soil. The study site was located in the Potshini catchment in Kwazulu-Natal (South Africa), an area heavily grazed by livestock. We conducted two rainfall simulations on three 1 m(-2) control (no dung) and six dung-treated plots in December 2008, and repeated the study in June 2009 on the same plots. Natural populations of dung beetles were allowed to colonise the dung. Simulations were conducted for 30 min at an intensity of 30 mm h(-1). Key variables calculated were pre-runoff amounts (Pi), infiltration ratios (Ki), and soil losses. Samples were collected for bulk density determination during the same time periods in order to measure differences in porosity and moisture in control and dung-treated plots at different depths. Using multivariate statistics we found significant differences between dung-treated and control plots in three of four simulations. After 48 h of beetle activity, Pi and Ki values were significantly increased and remained at elevated levels six months later. Soil losses were initially higher in dung-treated plots than controls, but had declined to less than control values after six months. Bulk density in the A-horizon (0-10 cm) was significantly reduced after 48 h of beetle activity and remained so for six months. No difference in bulk density was observed at greater depths. Soil moisture initially increased significantly in the A-horizon, as well as at 20 and 30 cm depths after six months of activity. We conclude that dung beetles positively influence hydrological properties of the soil by increasing water infiltration and soil porosity, and reducing surface water runoff. Contrasting effects on soil losses are problematic to reconcile from this study. High losses initially observed may be offset in the long-term by reductions associated with the increased infiltration ratios, though this remains to be confirmed.
Published: 2010
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27. Runoff and sediment losses from 27 upland catchments in Southeast Asia: Impact of rapid land use changes and conservation practices

Author: Christian Valentin, Olivier Ribolzi, N. Silvera, Tran Duc Toan, Do Duy Phai, K. Subagyono, T. Vadari, Fahmuddin Agus, A. de Rouw, A. Boosaner, Jean-Pierre Bricquet, K. Phachomphonh, R. Alamban, Didier Orange, Vincent Chaplot, Pascal Podwojewski, T. de Guzman, Jean-Pierre Thiébaux, Jean-Louis Janeau, Biogéochimie et écologie des milieux continentaux (Bioemco), Centre National de la Recherche Scientifique (CNRS)-AgroParisTech-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Recherche Agronomique (INRA)-École normale supérieure - Paris (ENS Paris), International Water Management Institute - South East Asia (IWMI-SEA), IWMI, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), International Water Management Institute [CGIAR, Sri Lanka] (IWMI), Consultative Group on International Agricultural Research [CGIAR] (CGIAR)-Consultative Group on International Agricultural Research [CGIAR] (CGIAR), École normale supérieure - Paris (ENS-PSL), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS)
Subjects: 010504 meteorology & atmospheric sciences, Land management, [SDV.SA.SDS]Life Sciences [q-bio]/Agricultural sciences/Soil study, 01 natural sciences, Soil management, Shifting cultivation, 0105 earth and related environmental sciences, 2. Zero hunger, Cassava, Ecology, Land use, Agroforestry, Upland rice, 04 agricultural and veterinary sciences, 15. Life on land, 6. Clean water, Maize, Steep slopes, 040103 agronomy & agriculture, Erosion, Land degradation, Soil erosion, 0401 agriculture, forestry, and fisheries, Environmental science, Animal Science and Zoology, Soil conservation, Surface runoff, Agronomy and Crop Science
Abstract: Rapid changes in upland farming systems in Southeast Asia generated predominantly by increased population pressure and 'market forces' have resulted in widespread land degradation that has been well documented at the plot scale. Yet, the links between agricultural activities in the uplands and downstream off-site effects remain largely unknown because of the difficulties in transferring results from plots to a larger scale. Many authors have thus pointed out the need for long-term catchment studies. The objective of this paper is to summarize the results obtained by the Management of Soil Erosion Consortium (MSEC) over the last 5 years from 27 catchments in five countries (Indonesia, Laos, Philippines, Thailand, and Vietnam). The purpose of the study was to assess the impacts of cultivation practices on annual runoff and erosion rates. Initial surveys in each catchment included topography, soils and land use. Monitoring included climatic, hydrologic and erosion (total sediment yield including bed load and suspended sediment load) data, land use and crop yields, and farmers' income. In addition, new land management options were introduced through consultations with farmers and evaluated in terms of runoff and erosion. These included tree plantations, fruit trees, improved fallow with legumes, maize intercropped with legumes, planted fodder, native grass strips and agro-ecological practices (direct sowing and mulch-based conservation agriculture). Regressions analyses showed that runoff during the rainy season, and normalized runoff flow coefficient based on erosive rainfall during the rainy season (rainfall with intensity exceeding 25 mm h(-1)) increase with the percentage of the catchment covered by maize. Both variables decrease with increasing soil depth, standard deviation of catchment slope (that reflects terrain roughness), and the percentages of the catchment covered by fallow (regular and improved), tree plantations and planted fodder. The best predictors of sediment yield were the surface percentages of maize, Job's tears, cassava and footpaths. The main conclusions generated from this study were: (i) soil erosion is predominantly influenced by land use rather than environmental characteristics not only at the plot scale but also at the catchment scale; (ii) slash-and-burn shifting cultivation with sufficiently long rotations (I year of cultivation, 8 years of fallow) is too often unjustly blamed for degradation; (iii) in its place, continuous cropping of maize and cassava promotes high rates of soil erosion at the catchment scale; (iv) conservation technologies are efficient in reducing runoff and total sediment yield at the catchment scale; (v) the adoption of improved soil management technologies by upland farmers is not a function of the degree of intensification of their farming system and/or of their incomes. The results suggest that if expansion of maize and cassava into already degraded upland systems were to occur due to increased demand for biofuels, there is a risk of higher runoff and sediment generation. A failure to adopt appropriate land use management strategies will result in further rapid resource degradation with negative impacts to downstream communities.
Published: 2008
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28. Effects of agricultural practices on the hydrodynamics of a deep tilled hardened volcanic ash–soil (Cangahua) in Ecuador

Author: Yann Leroux, Jean-Louis Janeau, Pascal Podwojewski, Biogéochimie et écologie des milieux continentaux (Bioemco), Centre National de la Recherche Scientifique (CNRS)-AgroParisTech-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Recherche Agronomique (INRA)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), École normale supérieure - Paris (ENS-PSL), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS)
Subjects: cangahua, Soil biodiversity, Runoff, agricultural practices, Soil science, runoff, 010501 environmental sciences, [SDV.SA.SDS]Life Sciences [q-bio]/Agricultural sciences/Soil study, 01 natural sciences, No-till farming, Soil series, Soil retrogression and degradation, Cangahua, 0105 earth and related environmental sciences, Earth-Surface Processes, 2. Zero hunger, Hydrology, Volcanic ash–soil, Soil morphology, 04 agricultural and veterinary sciences, 15. Life on land, Soil loss, Agricultural practices, Soil structure, volcanic ash soil, Soil water, 040103 agronomy & agriculture, 0401 agriculture, forestry, and fisheries, soil loss, Ecuador, Surface runoff, Geology
Abstract: The rehabilitation of indurate pyroclastic formations of the Ecuadorian Sierra (cangahua) paves the way for the development of new agricultural areas. The material derived from the fragmentation of the hardened volcanic ashes is strongly prone to pluvial erosion, essentially because it has a fine silty-sandy texture, and because contains no organic matter and no clay minerals. Rainfall simulation was implemented before and after three cycles of cultivation to asses the evolution of soil structure and its susceptibility to erosion. The cultivated plots were < 1% slope and the rainfall simulation tests were conducted after the harvest on bare surfaces. Two soil preparations, (coarse and fine) and four different agricultural practices, (organic matter, green manure, mineral fertilization, and zero fertilization) were evaluated; as well reference/control plots (uncultivated bare plots). Surface soil crusting occurred rapidly within the cultivated plots when compared to the recent tilled cangahua. Runoff and soil loss were generally higher on plots with lower structural stability and generally exhibited higher clay content. In agreement with the structural stability measured in a laboratory, organic matter inputs increase the soil porosity. This condition had no effect on the structural stability of the soil, resistance to crusting, and therefore little impact on surface runoff and erosion. The preferred option for land with these soils would be no tillage and a permanent soil cover (pasture) if they were to be utilised for agriculture.
Published: 2008
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29. Land-use impacts on surface runoff and soil detachment within agricultural sloping lands in Northern Vietnam

Author: Didier Orange, Pascal Jouquet, Christian Valentin, Duc Toan Tran, Jean-Louis Janeau, Pascal Podwojewski, Van Anh T. Nguyen, Biogéochimie et écologie des milieux continentaux (Bioemco), Centre National de la Recherche Scientifique (CNRS)-AgroParisTech-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Recherche Agronomique (INRA)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS), and MSEC
Subjects: Wet season, Sloping lands, 010504 meteorology & atmospheric sciences, [SDV.SA.SDS]Life Sciences [q-bio]/Agricultural sciences/Soil study, 01 natural sciences, Fodder, Acacia mangium, Earthworms, Land-use, 0105 earth and related environmental sciences, Earth-Surface Processes, 2. Zero hunger, Hydrology, Cassava, biology, Earthworm, 04 agricultural and veterinary sciences, 15. Life on land, biology.organism_classification, Eucalyptus, Surface runoff, 6. Clean water, Vietnam, 040103 agronomy & agriculture, 0401 agriculture, forestry, and fisheries, Environmental science, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Soil conservation, Soil detachment, Bioturbation
Abstract: Two consecutive years of investigation on soil surface features, surface runoff and soil detachment within 1-m(2) microplots on 40% slope highlighted the effects of land-use change, vegetation cover and biological activity on the water pathways in Northern Vietnam. Three replicate plots were setup on each of five land-uses: cassava (CAS), grass fodder of Bracharia ruziziensis (BRA), a 3-year old fallow (FAL), tree stands of Acacia mangium and Venicia montana (FOR), and a fallow with regrowth of Eucalyptus regularly cut (EUC). The second year, two of the microplots under FAL and EUC were treated with herbicide (FALh, EUCh), one of them was burnt (FALh+b, EUCh+b). The highest yearly surface runoff coefficient of 16%, and soil detachment rate of 700 g m(-2) yr(-1) in average with a maximum of 1305 g m(-2) yr(-1) have been recorded under CAS. On FALh and FALh+b, runoff ratios were 8.7 and 13.5%, respectively and detachment rates were 86 and 389 g m(-2). On FAL and BRA the yearly runoff ratio varied from 5.9 to 9.8% but the detachment rate was limited at 24 to 35 g m(-2). FOR and EUC annual runoff was
Published: 2008
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30. Agricultural changes, water quality and health: investigating the health status of populations living in an agricultural irrigated area, using spatial analysis, in Phrae province, Thailand

Author: Vincent Herbreteau, Jean-Paul Gonzalez, Wasana Khaungaew, Gérard Salem, Jean-Louis Janeau, Center of Excellence for Vectors and Vector-Borne Diseases (CVVD), Mahidol University [Bangkok], Institut de Recherche pour le Développement, UR 178 Fundamentals & Domains of Disease Emergence (IRD UR178), Phrae provincial Public Health Office, Ministry of Public Health - Thailande, Laboratoire Espace, Santé et Territoires (LEST), Laboratoire Dynamiques Sociales et Recomposition des Espaces (LADYSS), Université Paris 1 Panthéon-Sorbonne (UP1)-Université Paris 8 Vincennes-Saint-Denis (UP8)-Université Paris Nanterre (UPN)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Université Paris 1 Panthéon-Sorbonne (UP1)-Université Paris 8 Vincennes-Saint-Denis (UP8)-Université Paris Nanterre (UPN)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Sols, usages des terres, dégradation, réhabilitation (SOLUTIONS), Laboratoire d'économie et de sociologie du travail (LEST), and Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: SYSTEME D'INFORMATION GEOGRAPHIQUE, INNOVATION, PRODUCTION AGRICOLE, QUALITE DE L'EAU, PATHOLOGIE, North Thailand, ENVIRONNEMENT, GIS, human health, POLITIQUE DE SANTE, water quality, PREVALENCE, IRRIGATION, environmental changes, [SDV.SPEE]Life Sciences [q-bio]/Santé publique et épidémiologie, SANTE PUBLIQUE, DEVELOPPEMENT RURAL, REPARTITION GEOGRAPHIQUE, IMPACT SUR L'ENVIRONNEMENT
Abstract: International audience; Drastic environmental changes have occurred in Thailand during the twentieth century, along with the population growth and consecutive agricultural development consequently threatening the ecosystems. Infrastructures, and especially water reservoirs, were built to increase and improve the agricultural production. These changes have modified irreversibly the biotopes and, above all, the hydrographical network and water quality. In an effort to assess and monitor their consequences on human health, a health Geographic Information System was developed in Phrae province, North Thailand, focusing on the Mae Thang watershed, its reservoir and irrigated area downstream. In partnership with Phrae provincial Public Health Office, all patients' cases from 78 different pathologies, reported in Phrae rural areas from 1997 to 2004, were integrated and incidences were calculated among all the 693 villages, where patients and families live. Health infrastructures were also localized to assess the health offer, access, and recourse. Overall higher prevalence was recorded in Mae Thang study area as compared to the whole province, especially for infectious diseases that could be linked to water quality, as well as for upstream villages compared to those downstream. Marked geographical heterogeneity in disease prevalence between villages showed the importance of the choice of the study scale and the need for a public health survey at the village level to answer the hypotheses raised by the present observations.
Published: 2006

31. Un encroûtement des sols limitant l'infiltration

Author: José Luis González Barrios, Jérôme Poulenard, David Viramontes, Jean-Louis Janeau, Luc Descroix, Centre Alpin de Recherche sur les Réseaux Trophiques et Ecosystèmes Limniques (CARRTEL), Institut National de la Recherche Agronomique (INRA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), Centro National de Investigacion Diciplinaria, Partenaires INRAE, Instituto Mexicano de Technologia del Agua, Institut de Recherche pour le Développement, Luc Descroix, Juan Estrada, José Luis Gonzales Barrios, David Viramontes, and ProdInra, Migration
Subjects: surexploitation, RN, sol, droit d’usage, pâturage, déforestation, [SDV]Life Sciences [q-bio], érosion, 04 agricultural and veterinary sciences, 010501 environmental sciences, ruissellement, 01 natural sciences, [SDV] Life Sciences [q-bio], eau, pression démographique, Environmental studies, Geography & Development, SCI026000, 040103 agronomy & agriculture, réforme foncière, 0401 agriculture, forestry, and fisheries, Environmental science, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: Introduction Les sols interviennent sur le cycle de l'eau du fait de leurs propriétés hydriques (capacité de stockage, conductivité hydraulique, sorptivité, etc.) qui ont des relations directes avec leurs caractéristiques physico-chimiques (texture, structure, porosité, matière organique, etc.). Cependant, toutes ces propriétés et caractéristiques sont facilement modifiables par les activités humaines, ce qui implique aussi une modification de la réponse hydraulique des sols. Les études sur p...
Published: 2005

32. Runoff and soil erosion under rainfall simulation of andisols from the Ecuadorian paramo : effect of tillage and burning

Author: Jérôme Poulenard, Jean Collinet, Jean-Louis Janeau, and Pascal Podwojewski
Subjects: Hydrology, EROSION, SURFACE DU SOL, Soil science, Andisol, Bulk density, COEFFICIENT DE RUISSELLEMENT, PRATIQUE CULTURALE, Tillage, Hydraulic conductivity, INFILTRATION, Soil water, CONDUCTIVITE HYDRAULIQUE, Erosion, HYDRODYNAMIQUE, Soil horizon, DEGRADATION DU SOL, SIMULATION DE PLUIE, Surface runoff, Geology, Earth-Surface Processes
Abstract: In northern Ecuador, soils of high altitude grasslands (paramos) are mainly non-allophanic Andisols developed on Holocenic volcanic ash. These soils have a high water retention capacity and are the “water tank” of central Ecuador. To assess the effect of land use (burning and tillage) on soil hydrodynamic properties, rainfall simulation was conducted at two different sites. At Pichincha near Quito, the simulation was conducted on a recent volcanic ash soil comparing natural, tilled and burned plots. At El Angel, the simulation was conducted on a mature non-allophanic Andisol comparing natural, recently tilled and formerly cultivated plots. On natural plots, the infiltration rate was very high and sediment loss very low. Results for infiltration rate and runoff indicated that land use change on paramos increased runoff flow and reduced saturated hydraulic conductivity. Superficial reorganisation of the soil surfaces occurred on tilled plots at both sites. This crusting process was fast and resulted in surfaces with very low conductivity at Pichincha. The same processes seemed to be slower at El Angel. The soil surface of recent Andisols at Pichincha was prone to crusting whereas the mature Andisol, at El Angel, with a lower bulk density, was compacted when the kinetic energy of raindrops was high. Water repellency occurred after burning at Pichincha and following long natural air drying after tillage in the non-allophanic A horizon at El Angel. Water repellency combined with the low bulk density of soil aggregates explain the intensity of sediment losses in the abandoned soils after cultivation (Bare fallow plots). Erosion occurred in these areas through floating hydrophobic and stable aggregates.
Published: 2001

33. Rain-induced dispersal in Puccinia arachidis, studied by means of a rainfall simulator

Author: Jean-Louis Janeau and Serge Savary
Subjects: Canopy, EPIDEMIOLOGIE, biology, ARACHIDE, Plant Science, Horticulture, biology.organism_classification, Light rain, Arachis hypogaea, Spore, DISPERSION, Agronomy, Rainfall simulator, MICROCLIMAT, Botany, ETUDE COMPARATIVE, Puccinia arachidis, ETUDE EXPERIMENTALE, Biological dispersal, SPORE, ROUILLE, SIMULATION DE PLUIE, Agronomy and Crop Science, Urediniospore
Abstract: A rainfall simulator was used on groundnut (Arachis hypogaea) plots artificially infected withPuccinia arachidis in order to study urediniospore dispersal caused by various amounts of rainfall. Several trapping method were used to compare dry, splash and drip dispersal caused by rain. The spore liberation mechanisms activated by rain and the flows of spores which they generate can be studied at the infected canopy or at the sporulating lesion scales. Two systems referring to these scales were considered to discuss the results. Dry dispersal seemed preponderant. The spore content of the lesions in the canopy was strongly reduced by rain. The results indicated that light rain showers may promote disease dispersal, whereas it may be hampered by heavy showers. Een regensimulator, een krachtig beregeningsapparaat, werd ingezet boven een aantal aardnoot-(Arachis hypogaea) veldjes geinoculeerd met de aardnootroest (Puccinia arachidis) om de uredosporenverspreiding te bestuderen bij verschillende hoeveelheden regenval. Diverse vangtechnieken werden toegepast om droge verspreiding, spatverspreiding en druipverspreiding ten gevolge van regen te vergelijken. De sporeninhoud van de sporenhoopjes op het gewas werd door regen sterk verminderd. De resultaten, verkregen in twee verschillende, maar elkaar aanvullende analyses, geven aan dat lichte regenbuien de ziekteverspreiding bevorderen, terwijl zware buien deze zouden afremmen.
Published: 1986
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33 results on '"Jean-Louis Janeau"'

1. Experimental and modelling evidence of splash effects on manure borne Escherichia coli washoff

2. Water uptake plasticity of savanna trees in encroached grassland: small trees match the mature trees

3. Research for development in the 21st century

4. Mechanisms of lateral and linear extension of gullies (dongas) in a subhumid grassland of South Africa

5. Higher runoff and soil detachment in rubber tree plantations compared to annual cultivation is mitigated by ground cover in steep mountainous Thailand

6. Land use strongly influences soil organic carbon and bacterial community export in runoff in tropical uplands

7. Experimental and modelling evidence of short-term effect of raindrop impact on hydraulic conductivity and overland flow intensity

8. Effect of land use and hydrological processes on Escherichia coli concentrations in streams of tropical, humid headwater catchments

9. Seasonal variability of faecal indicator bacteria numbers and die-off rates in the Red River basin, North Viet Nam

10. Contradictory hydrological impacts of afforestation in the humid tropics evidenced by long-term field monitoring and simulation modelling

11. Mixing of biochar with organic amendments reduces carbon removal after field exposure under tropical conditions

12. Influence of earthworms and termites on runoff and erosion in a tropical steep slope fallow in Vietnam: A rainfall simulation experiment

13. Impact of compost, vermicompost and biochar on soil fertility, maize yield and soil erosion in Northern Vietnam : a three year mesocosm experiment

14. Water and health: what is the risk and visible burden of the exposure to environmental contaminations? Insights from a questionnaire-based survey in Northern Thailand

15. Off-site impacts of agricultural composting: role of terrestrially derived organic matter in structuring aquatic microbial communities and their metabolic potential

16. CDOM fluorescence as a proxy of DOC concentration in natural waters: a comparison of four contrasting tropical systems

17. Influence of buffalo manure, compost, vermicompost and biochar amendments on bacterial and viral communities in soil and adjacent aquatic systems

18. Soil erosion, dissolved organic carbon and nutrient losses under different land use systems in a small catchment in northern Vietnam

19. Positive versus negative environmental impacts of tree encroachment in South Africa

20. Grass competition is more important than seed ingestion by livestock for Acacia recruitment in South Africa

21. The indirect impact of encroaching trees on gully extension : a 64 year study in a sub-humid grassland of South Africa

22. Impact of land use change and rainfall on sediment and carbon accumulation in a water reservoir of North Thailand

23. Rainfall simulation to identify the storm-scale mechanisms of gully bank retreat

24. Water funnelling by the crown of Flourensia cernua, a Chihuahuan Desert shrub

25. Influence of grass soil cover on water runoff and soil detachment under rainfall simulation in a sub-humid South African degraded rangeland

26. Dung beetles (Coleoptera: Scarabaeidae) can improve soil hydrological properties

27. Runoff and sediment losses from 27 upland catchments in Southeast Asia: Impact of rapid land use changes and conservation practices

28. Effects of agricultural practices on the hydrodynamics of a deep tilled hardened volcanic ash–soil (Cangahua) in Ecuador

29. Land-use impacts on surface runoff and soil detachment within agricultural sloping lands in Northern Vietnam

30. Agricultural changes, water quality and health: investigating the health status of populations living in an agricultural irrigated area, using spatial analysis, in Phrae province, Thailand

31. Un encroûtement des sols limitant l'infiltration

32. Runoff and soil erosion under rainfall simulation of andisols from the Ecuadorian paramo : effect of tillage and burning

33. Rain-induced dispersal in Puccinia arachidis, studied by means of a rainfall simulator

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33 results on '"Jean-Louis Janeau"'

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