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Soils are key components of our ecosystems and provide 95%–99% of our food. This importance is reflected by an increase in participatory citizen science projects on soils. Citizen science is a participatory research method that actively involves and engages the public in scientific enquiry to generate new knowledge or understanding. Here, we review past and current citizen science projects on agricultural soils across Europe. We conducted a web-based survey and described 24 reviewed European citizen science projects in the light of the 10 principles of citizen science and identified success factors for citizen science. Over 66% of the projects generated soil biodiversity data; 54% and 42% of the projects generated data on vegetation cover and soil organic carbon, respectively. Our findings show that soil citizen science projects aligned with the 10 principles of citizen science offer an unexploited resource for European soil health research. We conclude that promoting co-creation, fostering knowledge-sharing networks and enabling long-term communication and commitment with citizens are success factors for further development of citizen science on soils.

Eutrophication is one of the most common causes of water quality impairment of inland and marine waters. Its best-known manifestations are toxic cyanobacteria blooms in lakes and waterways and proliferations of green macro algae in coastal areas. The term eutrophication is used by both the scientific community and public policy-makers, and therefore has a myriad of definitions. The introduction by the public authorities of regulations to limit eutrophication is a source of tension and debate on the activities identified as contributing or having contributed decisively to these phenomena. Debates on the identification of the driving factors and risk levels of eutrophication, seeking to guide public policies, have led the ministries in charge of the environment and agriculture to ask for a joint scientific appraisal to be conducted on the subject. Four French research institutes were mandated to produce a critical scientific analysis on the latest knowledge of the causes, mechanisms, consequences and predictability of eutrophication phenomena. This paper provides the methodology and the main findings of this two years exercise involving 40 scientific experts.

Eutrophication is one of the most common causes of water quality impairment of inland and marine waters. Its best-known manifestations are toxic cyanobacteria blooms in lakes and waterways and proliferations of green macro algae in coastal areas. The term eutrophication is used by both the scientific community and public policy-makers, and therefore has a myriad of definitions. The introduction by the public authorities of regulations to limit eutrophication is a source of tension and debate on the activities identified as contributing or having contributed decisively to these phenomena. Debates on the identification of the driving factors and risk levels of eutrophication, seeking to guide public policies, have led the ministries in charge of the environment and agriculture to ask for a joint scientific appraisal to be conducted on the subject. Four French research institutes were mandated to produce a critical scientific analysis on the latest knowledge of the causes, mechanisms, consequences and predictability of eutrophication phenomena. This paper provides the methodology and the main findings of this two years exercise involving 40 scientific experts.

Eutrophication is one of the most common causes of water quality impairment of inland and marine waters. Its best-known manifestations are toxic cyanobacteria blooms in lakes and waterways and proliferations of green macro algae in coastal areas. The term eutrophication is used by both the scientific community and public policy-makers, and therefore has a myriad of definitions. The introduction by the public authorities of regulations to limit eutrophication is a source of tension and debate on the activities identified as contributing or having contributed decisively to these phenomena. Debates on the identification of the driving factors and risk levels of eutrophication, seeking to guide public policies, have led the ministries in charge of the environment and agriculture to ask for a joint scientific appraisal to be conducted on the subject. Four French research institutes were mandated to produce a critical scientific analysis on the latest knowledge of the causes, mechanisms, consequences and predictability of eutrophication phenomena. This paper provides the methodology and the main findings of this two years exercise involving 40 scientific experts.

Catchment studies on water quality started in the 1960s, when scientists identified long-term environmental impacts and realized the complexity involved in environmental degradation and recovery. Since scientists need to understand biogeochemical and hydrological processes in detail, long-term observatories have been established over time, particularly in the field of catchment hydrology and biochemistry. The AgrHyS (for “AgroHydroSystem”) observatory comprises two small catchments in Brittany (France) and this article unfolds the evolution over 50 years of the scientific questions and related observations and studies in one of them, the Kervidy-Naizin catchment. While a well-defined set of variables was monitored since the beginning (the “basic observatory basket”), the research topics and additional monitored variables were much broader. The first 25 years focused on hydrological and biogeochemical processes, while the next 25 years focused on more integrated issues related to soil ecology and landscape biogeochemical cycles. The AgrHyS observatory has succeeded in fostering interdisciplinary research. The current challenge is the engagement of the observatory in international networks to enable inter-comparison of hydro-systems response to gradients of different land use and environmental conditions., Los estudios sobre calidad de agua en cuencas empezaron en los años 60, cuando los científicos identificaron el alcance de los impactos medioambientales a largo plazo y reconocieron la complejidad de la degradación y recuperación medioambiental. Dado que los científicos necesitan entender los procesos bioquímicos e hidrológicos en detalle, a lo largo del tiempo se han ido estableciendo observatorios a largo plazo, especialmente en relación con la hidrología y la bioquímica en cuencas. El observatorio AgrHyS (de “AgroHydroSystem”) incluye dos pequeñas cuencas en Bretaña (Francia) y este artículo explica la evolución de las preguntas científicas planteadas y las observaciones y estudios asociados a lo largo de 50 años en una de ellas, la cuenca de Kervidy-Naizin. Si bien un conjunto de variables bien definidas se han monitorizado desde el principio (constituyendo la “cesta básica del observatorio”), los temas de investigación y el seguimiento de variables adicionales ha sido mucho más amplio. Los primeros 25 años se centraron en procesos hidrológicos y bioquímicos y los 25 años siguientes se centraron en cuestiones más integrales relacionadas con la ecología del suelo y los ciclos bioquímicos del paisaje. En este sentido, el observatorio AgroHyS ha sabido fomentar con éxito una investigación multidisciplinar. El reto actual es la integración de este observatorio en redes internacionales que permitan la inter-comparación de la respuesta de los sistemas hydrológicos en gradientes de condiciones ambientales y de usos del suelo diferentes.

Catchment studies on water quality started in the 1960s, when scientists identified long-term environmental impacts and realized the complexity involved in environmental degradation and recovery. Since scientists need to understand biogeochemical and hydrological processes in detail, long-term observatories have been established over time, particularly in the field of catchment hydrology and biochemistry. The AgrHyS (for “AgroHydroSystem”) observatory comprises two small catchments in Brittany (France) and this article unfolds the evolution over 50 years of the scientific questions and related observations and studies in one of them, the Kervidy-Naizin catchment. While a well-defined set of variables was monitored since the beginning (the “basic observatory basket”), the research topics and additional monitored variables were much broader. The first 25 years focused on hydrological and biogeochemical processes, while the next 25 years focused on more integrated issues related to soil ecology and landscape biogeochemical cycles. The AgrHyS observatory has succeeded in fostering interdisciplinary research. The current challenge is the engagement of the observatory in international networks to enable inter-comparison of hydro-systems response to gradients of different land use and environmental conditions., Los estudios sobre calidad de agua en cuencas empezaron en los años 60, cuando los científicos identificaron el alcance de los impactos medioambientales a largo plazo y reconocieron la complejidad de la degradación y recuperación medioambiental. Dado que los científicos necesitan entender los procesos bioquímicos e hidrológicos en detalle, a lo largo del tiempo se han ido estableciendo observatorios a largo plazo, especialmente en relación con la hidrología y la bioquímica en cuencas. El observatorio AgrHyS (de “AgroHydroSystem”) incluye dos pequeñas cuencas en Bretaña (Francia) y este artículo explica la evolución de las preguntas científicas planteadas y las observaciones y estudios asociados a lo largo de 50 años en una de ellas, la cuenca de Kervidy-Naizin. Si bien un conjunto de variables bien definidas se han monitorizado desde el principio (constituyendo la “cesta básica del observatorio”), los temas de investigación y el seguimiento de variables adicionales ha sido mucho más amplio. Los primeros 25 años se centraron en procesos hidrológicos y bioquímicos y los 25 años siguientes se centraron en cuestiones más integrales relacionadas con la ecología del suelo y los ciclos bioquímicos del paisaje. En este sentido, el observatorio AgroHyS ha sabido fomentar con éxito una investigación multidisciplinar. El reto actual es la integración de este observatorio en redes internacionales que permitan la inter-comparación de la respuesta de los sistemas hydrológicos en gradientes de condiciones ambientales y de usos del suelo diferentes.

We developed a parsimonious topography-based hydrologic model coupled with a soil biogeochemistry sub-model in order to improve understanding and prediction of soluble reactive phosphorus (SRP) transfer in agricultural headwater catchments. The model structure aims to capture the dominant hydrological and biogeochemical processes identified from multiscale observations in a research catchment (Kervidy–Naizin, 5 km2). Groundwater fluctuations, responsible for the connection of soil SRP production zones to the stream, were simulated with a fully distributed hydrologic model at 20 m resolution. The spatial variability of the soil phosphorus content and the temporal variability of soil moisture and temperature, which had previously been identified as key controlling factors of SRP solubilization in soils, were included as part of an empirical soil biogeochemistry sub-model. The modelling approach included an analysis of the information contained in the calibration data and propagation of uncertainty in model predictions using a generalized likelihood uncertainty estimation (GLUE) "limits of acceptability" framework. Overall, the model appeared to perform well given the uncertainty in the observational data, with a Nash–Sutcliffe efficiency on daily SRP loads between 0.1 and 0.8 for acceptable models. The role of hydrological connectivity via groundwater fluctuation and the role of increased SRP solubilization following dry/hot periods were captured well. We conclude that in the absence of near-continuous monitoring, the amount of information contained in the data is limited; hence, parsimonious models are more relevant than highly parameterized models. An analysis of uncertainty in the data is recommended for model calibration in order to provide reliable predictions.

Agricultural intensification has greatly decreased grassland surface area in some regions, thus changing grassland management and modifying environmental and socio-economic systems. Therefore, knowledge about grassland management practices in farming systems is needed for sustainable agriculture. In this context, the PaturMata model simulates grassland management at the farm scale. The PaturMata model simulates grassland dynamics and several factors such as farming practices, grass consumption, and fertilization. The model takes into account environmental and farming system parameters such as climate, field number, size, and location; livestock units; and conventional or organic agriculture. Here, we first ran the model under climatic conditions favorable to grass growth for four farms on an experimental site located in western France. Biophysical variables extracted from remote-sensing images were used to initialize PaturMata, whose predictions were compared to on-site surveys. We generated forecasting scenarios of the same farms under different climatic conditions. Results show that PaturMata predicts a 70 % decrease in grass consumption, a 50 % decrease in the number of annual grazing periods, and a 60 % increase in the amount of conserved forage consumed, when conditions are unfavorable to grass growth. We conclude that the PaturMata model can help design farms and management strategies capable of coping with a wide range of conditions.

Agricultural intensification has greatly decreased grassland surface area in some regions, thus changing grassland management and modifying environmental and socio-economic systems. Therefore, knowledge about grassland management practices in farming systems is needed for sustainable agriculture. In this context, the PaturMata model simulates grassland management at the farm scale. The PaturMata model simulates grassland dynamics and several factors such as farming practices, grass consumption, and fertilization. The model takes into account environmental and farming system parameters such as climate, field number, size, and location; livestock units; and conventional or organic agriculture. Here, we first ran the model under climatic conditions favorable to grass growth for four farms on an experimental site located in western France. Biophysical variables extracted from remote-sensing images were used to initialize PaturMata, whose predictions were compared to on-site surveys. We generated forecasting scenarios of the same farms under different climatic conditions. Results show that PaturMata predicts a 70 % decrease in grass consumption, a 50 % decrease in the number of annual grazing periods, and a 60 % increase in the amount of conserved forage consumed, when conditions are unfavorable to grass growth. We conclude that the PaturMata model can help design farms and management strategies capable of coping with a wide range of conditions.

Agricultural intensification has greatly decreased grassland surface area in some regions, thus changing grassland management and modifying environmental and socio-economic systems. Therefore, knowledge about grassland management practices in farming systems is needed for sustainable agriculture. In this context, the PaturMata model simulates grassland management at the farm scale. The PaturMata model simulates grassland dynamics and several factors such as farming practices, grass consumption, and fertilization. The model takes into account environmental and farming system parameters such as climate, field number, size, and location; livestock units; and conventional or organic agriculture. Here, we first ran the model under climatic conditions favorable to grass growth for four farms on an experimental site located in western France. Biophysical variables extracted from remote-sensing images were used to initialize PaturMata, whose predictions were compared to on-site surveys. We generated forecasting scenarios of the same farms under different climatic conditions. Results show that PaturMata predicts a 70 % decrease in grass consumption, a 50 % decrease in the number of annual grazing periods, and a 60 % increase in the amount of conserved forage consumed, when conditions are unfavorable to grass growth. We conclude that the PaturMata model can help design farms and management strategies capable of coping with a wide range of conditions.

La salinisation des sols constitue un risque majeur du développement de l’irrigation dans le monde. Dans le Delta du Fleuve Sénégal, l’existence d’une nappe phréatique salée et proche de la surface du sol accentue ce risque. Une modélisation des transferts hydriques a été réalisée pour mieux évaluer ce risque. Elle a été faite à partir du code Hydrus sur l’ensemble du cycle cultural et a pris en compte deux types de sol et deux modes de culture de cette région : la simple et la double culture. Elle a permis d’estimer les flux hydriques descendants pendant la phase d’irrigation par submersion, et les flux hydriques et salins ascendants pendant la phase d’irrigation et de non-irrigation. Cette modélisation indique que : i) le toit de la nappe salée remonte d’environ 50 cm pendant la phase d’irrigation; ii) une zone non saturée de faible épaisseur subsiste entre la surface inondée et la nappe; iii) l’infiltration cumulée est deux fois plus forte en double qu’en simple culture; et iv) la forte évaporation durant la phase de non-irrigation peut faire remonter entre 5,5 à 6 t de sels par ha et par an, selon les sols et les conditions de culture. Cette modélisation, qui s’appuie sur des mesures in situ des paramètres hydrodynamiques, devra être confrontée à des observations in situ de flux. Elle devra intégrer des processus non pris à ce stade tel que le piégeage d’air. Les relevés piézométriques depuis dix ans montrent, par ailleurs, un léger relèvement du niveau de la nappe salée. L’ensemble de ces résultats est suffisamment préoccupant pour préconiser, dans le cas d’une irrigation par submersion, la mise en place d’un drainage superficiel pour éviter le relèvement de la nappe et assurer l’évacuation des sels hors de la nappe et, par là, la pérennisation de l’agriculture dans cette région du Delta du fleuve Sénégal, Soil salinisation is a major hazard of the extension of irrigation in the world. In the Delta of the Senegal River Valley, a highly saline groundwater close to the soil surface increases this hazard. A water and salt modeling by means of the Hydrus code has been performed to evaluate this hazard. Two soil types and two crop systems, a single and a double one, have been considered. The calculations have been performed on the complete agricultural cycle to determine water flows going down during the irrigation phase, and water and salt flows ascending to the soil surface during the irrigation and non irrigation phases. The modeling shows that: 1) the recharge due to the irrigation period induces an elevation of the water table of about 50 cm; 2) an unsaturated zone persists between the flooded surface and the water table; 3) the cumulative infiltration is two times higher in the double crop rice system than in the single crop system; 4) the high evaporation during the dry phase causes an ascension of from 5.5 to 6 t of salts per ha and per year according to the soil type and the crop system. This modeling, which was based on field measurements of hydrodynamic properties, has to be validated by field observations of the fluxes. Some processes such as air trapping should be tested. Piezometer monitoring over the past 10 years indicates a slight rise in the saline water table. All these results demonstrate the relevance of setting up a surficial drainage system for the flooded irrigation fields, to avoid an elevation of the water table and to evacuate salts from the soil surface, in order to perpetuate agriculture in the Delta of the Senegal River Valley.

This study deals with solute transfer in the vertical continuum between the unsaturated zone and shallow groundwater of a weathered granite aquifer in the Kerbernez headwater catchment of western France. The objectives are (i) to determine the mechanisms responsible for solute transfer in the unsaturated and water-table fluctuation zones of the aquifer, and (ii) to analyse the implications of these results on solute transfer times at the catchment scale. An experimental site located in the plateau area of the catchment was equipped with 6 tensiometers, 18 ceramic cups at depths from 0.25 to 2.5 m and 7 piezometers from 3 to 20 m. Measurements of hydraulic head and water sampling were,carried out over a period of 2.5 years in the unsaturated zone (0-2 m), the water table fluctuation zone (2-9 m) and the permanently saturated zone (> 9 m). Two tracer experiments were carried out by applying two pulses of water, one enriched with deuterium and the other with bromide. Natural chloride concentrations, as well as deuterium and bromide concentrations, were analysed from solution samples. From the artificial tracer concentrations, two porosity compartments can be identified and partly quantified: (1) the slow-mobile porosity (36% of the bulk volume), accounting for the slow piston-flow transfer (2-3 m per year), and (2) the rapid-mobile porosity, which transfers small quantities of bromide at a rate of 19 cm h(-1) down to the water table. Natural chloride concentrations are characterised by a high temporal variability in the water-table fluctuation zone, whereas the concentrations remain steady in time in the permanently saturated zone (42 mg l(-1) at 20 m depth). The temporal variability is related to the water-table fluctuations and follows the same pattern each hydrological year, i.e. low concentrations during rising water-table followed by a progressive increase in concentrations during the periods of high piezometric level and water-table recession. This pattern is exp