SOILSERV ANR project: The three main outcomes

The SOILSERV ANR project conducted from 2017-2021 combined biophysical and socio-economic approaches to assess at different spatial scales ecosystem services of agricultural soils within mixed agroecosystems involving crops, livestock and uncultivated areas and to analyse their economic valuation in farmers’ choices or their consideration in territory planning. To address the various scales, the project relied on three main study sites selected as they offer sound existing preliminary information, in particular the Kervidy-Naizin site (a AgrHyS observatory).

Carbon sequestration in cultivated soils

The dynamics of carbon stocks in the ploughed soils of the Kervidy-Naizin catchment were analyzed based on two sampling campaigns carried out in 2013 and in 2018. Carbon stocks were assessed and associated uncertainties were estimated from three different methods: deterministic, stochastic and experimental approaches. The majority of sites have lost carbon over the period (-0.05 +/- 0.06 kg C/m2/year), especially the soils under permanent grasslands (0.13+/- 0.08 kgC/m2/year).

Services and Disservices related to soil biodiversity

Biological, environmental and agronomical data were collected in 92 points over the Kervidy-Naizin catchment and combined with agronomical past history since 2012 (crop rotation, ploughing actions, number of years of meadows) from previous programs and long-term observatory records. Different models (RandomForest, Gradient Boosting Trees, Cubist, Generalised linear mixed models) were compared and highlighted the major role played by pH and texture, the bulk density and the hydromorphic state as key drivers, and the crucial importance of the field’s agronomical history (e.g. number of years of meadow in crop rotation) in affecting earthworm spatial distribution at the catchment/landscape scale.

Modelling soil ecosystem services

The STICS model (Simulateur mulTIdisciplinaire pour les Cultures Standards, v8.4) was used to simulate soil-atmosphere-crop interactions and quantify ecosystem service provision. Simulations were carried out on 83 points combining the 2018 campaign with existing data and experts. We considered six ecosystem services benefiting two types of stakeholders at the local scale and each service was quantified according to a specific indicator and a specific temporal resolution. The provisioning services (biomass provision, water and N provision for crops) benefited local farmers and were evaluated according to the cropping period via the simulated yield and water/N uptakes. The climate change regulation service benefited citizens (including farmers) and was estimated over 20 years (1998-2018) via the simulated C stocks. The groundwater recharge and water quality regulation also benefited to all citizens and were calculated according to the water year as the simulated flux of water draining to the groundwater and the amount of N retained in soil.

References

Fossey M., Angers D., Bustany C., Cudennec C., Durand P., Gascuel-Odoux C., Jaffrezic A., Peres G., Besse C. and Walter C. 2020 - A Framework to Consider Soil Ecosystem Services in Territorial Planning. Front. Environ. Sci. 8:28. https://doi.org/10.3389/fenvs.2020.00028

Pérès G., Benard Y., Fossey M., Plantegenest M. and Walter C. Key drivers of earthworm community distribution at landcape scale and ecosystem service associated. International Conference Soil Zoology, Bolzano, Italy, August 2021.

Tabaud L., Walter C., Blancfene C., Gascuel C., Lemercier B., Michot D., and Pichelin P. Assessment of nitrogen and organic carbon stocks in agricultural soils:uncertainties and significance of temporal evolution, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-10588, https://doi.org/10.5194/egusphere-egu21-10588, 2021.