Search

4 páginas.- 14 referencias.- Free Access, Soil can be seen as an important and delicate interfacebetween the biosphere, hydrosphere, atmosphere andlithosphere. Biogeochemical processes occurring at thisinterface are crucial for maintaining soil ecosystem func-tion, plant productivity and water quality. Aside fromcontrolling the fate of pollutants, this interface plays akey role in the biogeochemical cycles and thus has a rolein soils acting as a source or sink of greenhouse gases.With this in mind, we decided to organize the 8thInternational Symposium on Interactions of Soil Mineralswith Organic Components and Microorganisms (ISMOM2019), with the focus on “Understanding Soil Interfacial Reactions for Sustainable Soil Management and Climatic Change Mitigation”. This meeting took place in Seville,Spain, during 23–28 June 2019, and was organized by Heike Knicker and Francisco J. González-Vila from the IRNAS-CSIC, Seville, as a part of the interCongress series of international symposia of Commission 2.5 (Soil chemical, physical and biological interfacial reactions) of theInternational Union of Soil Sciences (IUSS).During the meeting, we had the pleasure of presenting the contributions of 170 participants from 33 countries. In total, 185 abstracts were submitted, of which 157 were finally presented as plenary (two), keynote (five) or oral (54) talks along with 96 posters. The number, diversity and quality of the submitted abstracts, as well as the excellent work of the scientific committee, provided an interesting and well‐balanced scientific programme. The contributions were presented during the following six sessions. Soil as a C and N sink: Who is the major player – soil minerals, soil organic matter quality, microbial activity or their interplay? New physical, chemical and biological analytical approaches: How can they lead us to a better understanding of soil interfaces? Ecological disturbances: How do mismanagement of soils (overgrazing, erosion, etc.) and natural disasters (fire, flooding, etc.) affect the interplay between soil minerals, SOM and microorganisms? Dynamics of pollutants at soil interfaces: What is new and how can environmental biotechnology be beneficial for soil restoration and bioremediation? Soil amendments (biochar, composts and digestates): How do they affect interactions at soil interfaces? Nutrient availability in soils: Can our knowledge on soil interfaces improve biotechnological approaches or soil management to decrease the need for artificial fertilizers? In order to increase the visibility of posters, a part of the time for the poster session was dedicated to a “pico‐session” during which poster presenters had a maximum of 2 min to advertise their work. This offer was well appreciated both by presenters, in particular by young researchers, and interested participants and greatly stimulated the following discussions at the poster boards. Considerable time for discussion and remaining questions was also provided after each session, an offer that was also well accepted by the audience. A special highlight was the Dr P.M. Huang Prize awarded to Dr. Rota Wagai from the National Institute for Agro‐Environmental Sciences, NIAES, Japan, for his outstanding and unique contributions to our understanding of the interaction of organic matter, minerals and microorganisms in the soil. Generous sponsorship from the IUSS Stimulus Fund, Commission 2.5 of the IUSS, the International Humic Substance Society (IHSS) and the University of Seville allowed travel grants to be awarded to young scientists and scientists from under‐funded countries, in addition to keynote speakers. The support by the IRNAS‐CSIC, as well as the sponsoring by Agrana AG, Bruker BioSpin GmbH, Analisis Vinicos, Abogase Legal SI and AMC Chemical & TRICHODEX, contributed to successfully providing this international platform for fruitful discussions between scientists and students from soil sciences, chemistry, biology, biochemistry, physics, ecology or environmental sciences., The papers collected together in this special issue of the European Journal of Soil Science reflect the diversity of communications at the conference. The following special issue contains a small collection of 14 papers based on presentations made at the meeting. As part of the section Soil as a C and N sink, the contribution of Briedis et al. (2021) describes a study dealing with the effects of land‐use types (native vegetation [NV] vs. no‐till system [NT]) on organic carbon (OC) stocks and on the chemical composition of organic matter (OM), seeking a better understanding of the OC build‐up in no‐till areas and the mechanisms that govern OC protection in highly weathered soils in Brazil. Applying solid‐state 13C nuclear magnetic resonance (NMR) spectroscopic analyses in soils fractionated into coarse and fine fractions by sieving, they concluded that “maintaining continuous NT is a sine qua non condition” to improve SOM contents. They confirmed further that the interactions of labile compounds with soil minerals can be seen as the driving factor for OM protection in soil. The article by Cissé, van Oort, Chenu, Essi, and Staunton (2021) shifts the focus to the soil organic nitrogen fraction and investigates the relative enrichment of SOM in the operationally defined fraction, glomalin‐related soil protein. This study relied on the “42‐Plots” long‐term bare fallow trial in Versailles, France, and challenged hypotheses on the fungal origin and intrinsic stability of this fraction. It was concluded that GRSP is continually produced by the recycling of soil organic matter, with no evidence that it is of predominantly arbuscular fungal origin. Soil pH and availability of sources of N contributed to the complex balance between protein synthesis and accumulation. The work by Le Bayon et al. (2021) introduced the use of X‐ray microcomputed tomography for characterizing earthworm‐derived belowground soil aggregates. It was presented in the section dedicated to New physical, chemical and biological analytical approaches. The calculation of density and size (down to 30 μm) allowed the authors to distinguish mineral and light organic and void spaces, and to compare pore size distribution in soils after the action of different earthworms. This major advance opens exciting possibilities for the study of organo‐mineral interfaces. A more pedogenesis‐related approach is presented by Pospíšilová and her coworkers (Pospíšilová et al., 2021). Applying X‐ray diffraction (XRD) on the fine earth and clay fractions of soils from the Litovelské Pomoraví (Czech Republic), they identified hydroxy‐interlayered vermiculites (HIV). Such minerals appear not to have been found in Bohemian and Moravian loess before. Based on their findings, they concluded that HIV and even vermiculite are pedogenic clay minerals. The paper by Wu, Wu, Huang, and Cai (2021) demonstrates how the interaction with mineral or organo‐mineral surfaces may have an important impact on molecular reactions. This study reports that one mineral in particular, birnessite, facilitates the conjugate transfer of plasmids and may initiate the formation of intracellular reactive oxygen species. Clay minerals may contribute to the global dissemination of antimicrobial resistance. The goal of the session Ecological disturbances was to present some new insights on the impact of (mis)management of soils or natural disasters and how they affect the interplay between soil minerals, SOM and microorganisms. Towards this goal, Escobar Ortega, Aguilar Vásquez, Ávila Alba, and García de Salamone (2021) evaluated the impact on the rhizosphere microbial communities of inclusion of cover crops in succession with soybean and plant growth‐promoting rhizobacteria (PGPR) inoculation. The underlying assumption of this work is that the inclusion of cover crops adds, through the input of crop residues to the soil, to the preservation of soil quality. However, using glyphosate to interrupt the growth of the cover crop is supposed to have a negative impact on the microbial rhizosphere communities that should be better understood. Therefore, they assessed whether the inoculation of two cover crops with A. brasilense and P. fluorescens, their growth interruption with glyphosate and the fertilization of cover crops at sowing, modify the functional and structural diversity of rhizosphere microbial communities. The study of the response of the microbial communities to changing management practices was also the objective of the work by Navas, Martín‐Lammerding, Hontoria, Ulcuango, and Mariscal‐Sancho (2021). They hypothesized that tillage type affects the abundance and size of macroaggregates, which in turn changes the microenvironment and the total abundances of fungi and bacteria within them. Evaluating the total abundance of bacteria (based on 16S rRNA analysis) and fungi (based on internal transcribed spacer analysis) inhabiting each aggregate fraction, they found that bacteria and fungi respond differently to changes in the distribution of aggregates induced by management practices. They further observed that in contrast to the fungal abundance, the distribution of bacteria in the aggregates was closely related to C and N concentrations. Another paper from Navas, Pérez‐Esteban, Torres, Hontoria, and Moliner (2021) investigated microbial communities along a gradient of metal contamination in a former copper mining area. Their underlying objective is to identify and exploit the metal resistance properties of microorganisms to use as biofertilizers to improve the efficiency of phytoremediation. Marked differences in abundances of species were observed along the contamination gradient and metal‐resistant genes were identified. Contaminated soils may be an important reservoir for useful microorganisms, notably Bradyrhizobium diazoefficiens and Pseudomonas aeruginosa, capable of both resisting large metal contents and also improving nutrient availability. Studying the fate of pollutants in soils is strongly associated with the study and understanding of their sorption behaviour. In line with this and within the fourth session Dynamics of pollutants at soil interfaces, Mikhail Borisover (2021) introduced a new approach to quantify sorption–desorption hysteresis using single‐point desorption isotherms in liquid‐phase sorption experiments in terms of the Gibbs free energy of non‐relaxed states. The study by Evans and Jacobs (2021) investigates the complexity of tertiary anion exchange reactions in soils from different horizons of alpine tundra soils in order to assess their impact on aluminium biogeochemistry. A combination of batch and column experimental approaches was used to follow oxalate/hydroxide/fluoride exchange along with aluminium solubilization. In recent years, concerns about the application of glyphosate have considerably increased. As a consequence, the behaviour of this widely used herbicide in soils has also been an issue discussed at the ISMOM after the presentation of Galicia‐Andrés, Tunega, Gerzabek, and Oostenbrink (2021), who investigate the molecular basis of the interactions between glyphosate and kaolinite, a clay mineral with high abundances in subtropical and tropical soils. Applying force‐field molecular dynamics simulation together with first principle calculations using a density functional theory‐based approach, they were in particular interested in the role of H‐bond formation as the precursor stage. They confirmed that kaolinite has an important contribution to the overall adsorption capacity of soils for glyphosate, specifically in its anionic form. Another study of an agrochemical was presented in the session dedicated to Soil amendments; the contribution of Aldana, Hazlerigg, Lopez‐Capel, and Werner (2021) presents results of batch studies in which the sorption and retention of atrazine, diuron, enrofloxacin, oxytetracycline and biochar applied in different doses to tropical soils with different texture was investigated. They identified rice husk biochar as an amendment that can efficiently reduce the leaching of the selected agrochemicals. However, because changes in soil properties due to the amendment may inadvertently lead to increased leaching, the authors conclude that the implementation of this approach should be conducted carefully and that field studies evaluating the long‐term effects of biochar‐amended soils on the fate of agrochemicals are still needed. Leiva‐Suárez et al. (2021) suggested the use of biochar, rich in nitrogen, as a slow‐release fertilizer, and studied the long‐term availability of N and P in sewage sludge‐derived hydrochars and pyrochars during a second cropping period. They prepared a soil that was previously amended with 13C‐ and 15N‐enriched hydrochars and pyrochars and was subjected to a first cropping period. After a second cropping period with Lolium perenne, the distribution of the isotopic labels between crop and soil was monitored. Hydrochars were identified as good candidates for long‐term fertilization and all amendments were reported to have comparable turnover rates in the long term, independently of their aromaticity and the native SOM. In another work presented in the session Nutrient availability in soils, Liu et al. (2021) tested the hypothesis that the efficiency of nitrification inhibitors can be increased by enhancing the nitrogen application rate. To test the hypothesis, field experiments with different N fertilization rates and the addition of nitrification inhibitor 3,4‐dimethylpyrazole phosphate (DMPP) were conducted and the respective efficacy of DMPP addition in reducing soil N2O emissions was determined. They suggest that ammonia‐oxidizing bacteria could be the dominant N2O emission contributors in nitrogen‐treated soils. They further reported that DMPP was more efficient at high nitrogen rates and concluded that DMPP application can be an efficient strategy to mitigate environmental risks related to N2O emissions from soils. We would like to thank EJSS for providing the opportunity for this special issue and acknowledge the great help and support of the Editor in Chief Professor Jennifer Dungait and the EJSS publication staff. Finally, we wish to thank the contributing authors and offer our sincere gratitude to all the reviewers, without whom this special issue could not have been completed. Last but not least, we thank all the participants of the 8th ISMOM for their activity, which turned the meeting into a lively and successful event. We are looking forward to continuing the discussions and interactions initiated at this meeting at the 9th ISMOM in 2024.

© 2017 British Society of Soil Science For the 70th Anniversary of the establishment of the British Society of Soil Science, this short paper explores the idea that research on soil organic matter has remained a central theme within soil science over the past 70 years, albeit with changing emphasis and application. The number of publications on soil organic matter has increased greatly in recent decades; for example, there were almost 35 000 journal papers with this theme in the decade 2007–2016. Several topics in research on soil organic matter, such as soil fertility, have endured for a number of decades, with publications found on soil organic matter and fertility in the decade 1947–1956. A search with other keywords occurring with soil, such as climate change, biodiversity, fertility, quality, health and security, showed that several topics did not appear before the 1970s and 1980s, but since then the sub-topics and applications have diversified. Carbon is a keyword that has become more associated with publications on soil organic matter; carbon is in over half of soil organic matter publications of the last decade. A closer examination of research on agricultural soil carbon sequestration since 1990 reveals that the focus of papers in the literature has changed over this period. A closer examination of papers on modelling shows that the next generation of soil organic matter models is developing from pseudo first-order decay models using conceptual pools and prescribed controls of turnover time to vertically resolved, microbially explicit models representing mineral surface and plant interactions. Given its higher policy profile during the last 2 years, research on soil organic matter and soil carbon sequestration is predicted to have a bright future. Highlights: The number of publications on soil organic matter has increased greatly in recent decades. Soil fertility research has endured for many decades, whereas other topics have diversified. Soil organic matter has been increasingly associated with carbon, which has changed the focus of papers since 1990. Expanding policy attention to soil organic matter research during the last 2 years suggests a bright future.