Tillage erosion affects crop yields and carbon balance in hummocky landscapes

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Soil erosion on arable land is a major environmental threat affecting various soil related ecosystem services. Traditionally water (and partly wind) erosion is studied, while erosion due to agricultural soil management (tillage erosion) is often ignored. Nevertheless, tillage erosion often has a similar magnitude as water erosion and can be even the dominate process in areas where erosive rainfall is rarer. The main goal of the project is to quantify the impacts of tillage erosion upon crop yields and upon feedbacks on the carbon cycle in a hummocky landscape in North-eastern Germany. It is hypothesized that tillage erosion increases in-field yield variability and decreases mean yields, but increase landscape soil carbon storage. The test region (Quillow catchment) is characterized by a strongly mechanized, intensive agriculture as well as small precipitation sums with regular dry spells. Agricultural production is, hence, very sensitive to interannual climate variability. In combination with a number of preliminary regional studies carried out by the PIs and the availability of long-term data-sets (ZALF) the region is ideally suited for this study. The working program combines (i) experimental approaches to determine erosion rates and C balance components, (ii) multi-temporal remote sensing of in-field variability of crop yields, (iii) and coupled soil erosion and C balance modelling (1960-2020). The project will close an important gap in our understanding of the interactions between tillage erosion, crop yields and carbon cycling in a representative hummocky landscape, where water erosion is small but shallow soils are especially sensitive to erosion processes. The test region in NE Germany is an important area of crop production which already suffers, especially in dry summers, from water shortage, which is most pronounce on eroded hilltops. Hence, the regions is ideally suited as showcase for many other hummocky regions of the world where intensively mechanized agriculture leads to pronounced tillage erosion.