Fostering Soil Organic Matter Stocks by Adapting Agricultural Management Practices – A Model Analysis

As part of the EU-Interreg project ‘Blue Transition – How to make my region climate resilient’, this study targets the climate change resilience of organic matter stocks and soil fertility in agricultural soils in a study region in Lower Saxony, Germany. The Federal Institute for Geosciences and Natural Resources together with the regional water authority (Water authority of Oldenburg and East Frisia) investigates options to adapt agricultural management practices to change the trajectory of the observed organic matter losses at many agricultural sites in the region.

Considered adaptations include the optimization of fertilizer application, tillage practices, crop rotations and choices in catch crop as well as a one-time deepening of the topsoil layer depth by 5 cm to increase the soil volume for potential organic matter accumulation.

The long-term development of carbon stocks is estimated by simulating the carbon and nitrogen dynamics in the soil in response to site-specific soil and weather conditions, management practices and adaptations thereof. The dynamics are modeled using the Soil-Vegetation-Atmosphere-Transfer-Model Daisy. The model analysis highlights the potentials and limitations of different management adaptations. It also shines a light on the implications for the pollution of groundwater resources by nitrate leaching as a byproduct of efforts to increase soil carbon stocks.