Landscape approach of soil organic matter dynamics in intensive mixed agrosystems, in the context of global change – MOSAIC

«These issue are addressed in a single long term research study site (ORE AgrHys). The site is heterogeneous in terms of cropping systems and environmental conditions: it is representative of intensive mixed agricultural area of western Europe, and presents gradients of soil water regime from welldrained soils to temporarily or permanently saturated soils. The project is interdisciplinary and will combine different approaches of SOM dynamics: advanced techniques regarding SOM dynamics (geochemistry, biology), and landscape perspective of production and environmental functions of agroecosystems (agronomy, landscape ecology). This program involves observations, experiments and modeling.«

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The challenge for agriculture in the coming years is to design sustainable and resilient systems that reconcile their production function and ecosystem services, on short-term (inter-annual scale) and on medium term (from one to several decades), in a changing environment. Soil organic matter (SOM) is a key element of agroecosystems resilience and sustainability: it affects both soil production and soil environmental functions (buffering nutrient transfer (NO3-, dissolved organic carbon (DOC)) to water bodies, and greenhouse gas emissions (e.g. N2O, CO2), mitigation of climate change, biodiversity). Landscape is the relevant scale (1) to consider the interactions between the anthropogenic and natural factors controlling the dynamics of SOM, (2) to consider organic matter and nutrient fluxes involved in SOM dynamics, (3) to address SOM impact on both production and environmental functions of soils in a combined way. A spatial perspective is crucial for an adequate assessment of global change effects, because contrasting drivers may control processes occurring at the plot scale and at the landscape scale.
The general objective of the project is to investigate SOM dynamics (stocks and related fluxes) in intensive mixed-agricultural landscape, and the impacts of global changes on SOM and on cropping systems resilience. Two components of global change are considered: climate change and change in cropping systems. The project focuses on quantifying and understanding the heterogeneity in SOM dynamics at landscape scale, in landscape presenting contrasted cropping systems in terms of organic matter inputs and soil water regime. The project is divided into three main research axis: (1) quantifying variability and co-variability of existing organization of cropping systems, environmental factors, and SOM stocks, over agricultural landscape, (2) better understanding of processes governing SOM dynamics in a range of cropping systems and environmental conditions, (3) modeling and prospective simulation of SOM dynamics over landscape. These issues will be addressed on a single long term research study site (Naizin catchment, ORE AgrHys). The site is heterogeneous in terms of cropping systems and environmental conditions: it is representative of intensive mixed agricultural area of western Europe, and presents gradients of soil water regime from well-drained soils to temporarily or permanently saturated soils. The project is interdisciplinary and will combine different approaches of SOM dynamics: advanced techniques regarding SOM dynamics (geochemistry, biology), and landscape perspective of production and environmental functions of agroecosystems (agronomy, landscape ecology). This program involves observations, experiments and modeling.
The results of this research will ultimately contribute to design landscape management strategies to adapting farming systems to global change.