SOil Functional diversity as an Indicator of sustainable management of Agroecosystems – SOFIA

The project builds on an experimental site of the Observatory in Environment (SOERE ) « Agroecosystems , Biogeochemical Cycles and Biodiversity « located at Estrées -Mons in the Somme department in France. This experiment provides a series of experimental treatments varying crop rotation , mineral inputs ( nitrogen fertilization ) and tillage. The project consists on the one hand to follow the course of a 4-year soil differentiation induced by these practices in terms of agricultural, physical and chemical variables for the soil. On the other hand , the project is striving to characterize the taxonomic and functional as well as the dynamics of earthworm communities, diversity of macro- invertebrates, micro fauna and bacterial and fungal communities. Finally some soil functions are quantified ( degradation , mineralization, CO2 and N2O emissions). The data produced are used to test and improve biotic and abiotic indicators.

The measurements obtained during the first two years of the experiment (2012 and 2013) show an early differentiation of experimental treatments, including an increase in organic matter and microbial activity in treatments with shallow tillage. The treatment receiving 50% of the maximum nitrogen fertilization, underwent a 10% decrease in biomass production. A doctoral program on the relationship between quality of crop residues, and functional changes in soil communities began in 2012.

The acquisition of knowledge is not linear in this project and field samplings of years 2013 and 2014 are crucial, as they represent +3 and +4 years after shift in agricultural practices.. It is therefore premature to consider the impact of this study. The thesis funded by the project is currently exploring some mechanistic hypotheses on the relationship between factors (residue quality) and soil functional diversity. Finally, a post-doctoral recruited in 2014 will be dedicated to the cross-analysis of the results obtained during the kinetics of differenciation.

The project has hosted yet several interns (BTS and Master level) and a PhD (in progress). Several posters were produced for the workshop of the French SOM network and of SOERE ACBB. Publication presenting SOFIA project has been written and published in a Tranfert-oriented article (International Innovation, September 2013)

www.research-europe.com/index.php/digital_magazine/

The "SOil Functional biodiversity as an Indicator of Agroecosystems management" (SOFIA) project aims at shading more light on environmental issues related to cropped agroecosystems management, climate change and biodiversity conservation. It specifically addresses the impact of agricultural practices on the taxonomic and functional diversity of living communities in the soil, and the effects of those practices on some of the functions the soil sustains: regulation (greenhouse gases emissions, carbon storage), supply (availability of nutrients for crop production) and maintenance of biodiversity (soil fauna and flora). This project brings together eight academic (universities, INRA) and one private (Agrotransfert) partners. It builds a part of its experimental design on the Estrées-Mons site (22 ha, Somme, north of France) managed by INRA and setup in 2010.

This site is dedicated to the study of long-term anthropogenic disturbance on biogeochemical cycles and biodiversity (ORE –ACBB) and focuses especially on disturbances brought by cropping. The site is characterized by a series of experimental treatments comprising varying levels of crop rotation (eg. annual, perennial and energy-based crop rotations), mineral inputs (nitrogen) and tillage practices. Hence, these treatments significantly modulate the amount, chemical nature and location of food resources for soil organisms but also their physical habitat.

All along the project, the partners will monitor the induced-differentiation of the agroecosystems setup 2010 in terms of agronomic variables (plant biomass production) and soil physical and chemical variables. Concomitantly and by taking into account the significance of ecosystem services supported soil organisms, the project will characterize earthworms, macro-invertebrates, microfauna, bacterial and fungal communities taxonomic and functional diversity as well as its dynamic.
Finally, some of the soil functions that are known to be greatly affected by these communities will be quantified: carbon and nitrogen mineralization, decomposition of plant residues, N2O emissions for instance. Laboratory experiments will also be performed and, both field and laboratory, results shall be used to test and improve biotic and abiotic indicators of soil functioning. In the end, the SOFIA project aims at the proposal of indicators that could better guide farmers choice, especially during transitions phases created by the evolution of cropping practices (introduction of energy crops, abandonment of tillage, reduced inputs, etc..). This project will also contribute to the improvement of indicators assessing the environmental impact of farming practices.