Erosion Impact on Nitrogen Turnover and Retention in Soil

Background and Objective

Soil erosion can be triggered by water, wind and tillage. Soil erosion and deposition is known to redistribute soil carbon. Since the carbon and nitrogen cycles in the soil are closely linked, it can be assumed that soil erosion has a strong influence on the nitrogen content and dynamics in the soil. Previous studies have often focused on individual aspects of the nitrogen cycle. However, to better understand nitrogen dynamics and stock changes in eroded soils, a comprehensive understanding of nitrogen turnover rates and availability is necessary, because only then can fertilization and management of these areas be sustainably improved.

Approach

The work program includes three experiments of varying complexity to study the effects of soil erosion on nitrogen turnover. For this purpose, ¹⁵N balance approaches and ¹⁵N labeling techniques are used and complemented by the application of the latest ¹⁵N model (Ntrace) to distinguish the gross nitrogen turnover processes in the soil. In order to gain a first understanding of the impact of soil erosion on nitrogen turnover, an in situ ¹⁵N field tracing experiment is carried out at two sites in north-eastern Germany. In two further experiments, the process-based understanding of nitrogen turnover using ¹⁵N and ¹⁴C labeling under controlled conditions is examined in more detail at research facilities of Thünen and ZALF.