In Germany, agriculture contributes around 12% to total greenhouse gas emissions. These come predominantly from animal husbandry and the soil. Neither with current technology nor with the technology under development will it be possible to reduce these emissions to zero. If we want to become climate neutral, we must actively remove carbon from the atmosphere. Plants can do this by taking CO2 from the air and splitting it into oxygen and carbon. If the carbon is stored long-term in the soil (humus), this counteracts climate warming. Soil organic carbon also improves soil health and protects against the consequences of climate change. Soil organic carbon build-up is thus a measure for climate mitigation and adaptation.

Plants use their comprehensive root system to absorb water and nutrients from the soil. Nutrients are derived from fertilization and especially from decomposed organic matter. The art of circularity oriented agriculture is to optimize tillage practices, fertilization and crop rotation choices towards improved soil structure, soil life, organic matter dynamics and root growth. The goal is to make the supply of water and nutrients to the plant roots as efficient as possible. The better the soils are prepared for this, the fewer external resources, such as mineral fertilizers, are needed.

Most of the biodiversity of agricultural systems resides in soil. The interactions among soil organisms have large effects on the quality of crops, the incidence of soil-borne plant and animal pests and diseases. Beneficial soil organisms have an essential role in agricultural productivity as they mediate nutrient cycling and soil organic matter dynamics, alter soil physicochemical properties and support plant growth. However, agricultural intensification is considered the main factor setting pressure on soil biodiversity. When confronted with future land use change, understanding the responses of soil biodiversity to different land use regimes is decisive for adequate land management. However, there is still an open question how consistently different soil organisms respond to land use intensification. Our research focuses on understanding and quantifying the functional role of soil fauna in agroecosystems as well as the effects of agricultural management on these organisms.

Almost half of the volume of fertile soils consists of pores of different shapes and sizes. They are largely formed by the activity of soil organisms and by the roots of plants. The large pores ensure that even heavy precipitation can seep into the soil, while water is held in the smaller pores by capillary forces. This allows soils to store large amounts of water, which can ensure the survival of plants even during longer dry periods. Soils also ensure that precipitation does not immediately end up in rivers. Without soils, flooding would be commonplace. At the same time, the soil’s pore space provides room for an enormous number of soil organisms. These are able not only to decompose organic residues and make them available to plants again, but also to break down pollutants. When managed properly, this makes biologically active soil a very efficient water filter and a guarantor for clean groundwater.