Moving the Frontier of Comparative Erosion Measurements under Different Agricultural Schemes – Development of a Long-term, High-resolution, 4D Erosion Measurement Site

Abstract

Erosion occurs in many fertile and agricultural intensively used regions world-wide. At the same time, scientists expect more frequent and intense erosive rainfall events and droughts with climate change. In combination with increasing urgency to reduce nutrients and pesticides, a reconciliation of interests from food and energy production with those of environmental protection (e.g., soil and water) and sustainability is challenging. Counter measures can significantly reduce surface runoff and erosion on sloping croplands. There is plenty of research on the efficiency of single measures, cultivation methods, or crops. However, we know little about combined effects of these factors and the influence of surface runoff on longer slope lengths. Further, changing climatic conditions and the needed reduction of herbicides question well-accepted knowledge from the last decades. Increasing agricultural machinery size and weight calls for larger than traditional plot sizes to create conditions representing up-to-date soil management. The Bavarian State Research Center for Agriculture (LfL) has established an experimental site (Erosion and Runoff Laboratory, EARL) in Ruhstorf (Lower Bavaria, Germany) to analyze the physical, social, and economic factors driving the local ongoing erosion (Figure 1). <fig><graphic xlink:href=23061_files/23061-00.jpg id=ID_0868fa44-1304-43e5-a90b-437095054b4f></graphic></fig> During long-term measurement campaigns, measures reducing erosion and improving the landscape‘s water retention will be assessed in combination with crop rotation schemes and new cultivation methods (i.e., crop selection, nutrient and pesticide management, cultivation methods, robotics, and precision farming). Drawing on other research groups‘ experiences in the UK, Switzerland, Austria, and elsewhere, ecologically promising and practical cultivation methods will be assessed for their erosion risk and resilience against weather extremes under controlled circumstances using an area of almost 6 ha. Each of 36 combined plot experiments (12 * 3 replications of 8.0, 9.5, and 11.0% slope) with plot sizes of 55 m x 6 m are complemented with smaller twin plots that include a rainfall simulator to generate additional data independent of weather or simulating future climate conditions. The UAV and in-situ monitoring is focused on a very high data point density in three spatial and one temporal dimensions (4D approach) and includes precise topographical, meteorological, soil, and agricultural data as well as digital sensor networks applying an internet-of-things technique. The datasets will be analyzed with deep learning approaches and modelling to transfer the results to catchment scales. Staff members of the LfL, the Chair of Hydrology and River Basin Management at the Technical University of Munich (TUM), and the Chair of Water and Soil Resource Research at the University of Augsburg designed the concept of the measurements, and plan and realize the installation of the plots. Supported by the TUM Institute of Measurement Systems and Sensor Technology, the experiment will be fully operational from 2024 (after an initialization phase of three years) and deliver data for more than ten years. Furthermore, major objectives are establishing an international scientific network and collaborative projects on the one hand, and the transfer of the generated scientific knowledge to practical day-to-day work of farmers and authority staff through talks, workshops, conferences, and field trips on the other. This contribution informs and includes the scientific community during the set-up phase about the operation and planned activities to build an international scientific network, discuss our approaches, efficiently use the existing scientific knowledge, and initiate future collaborations around the measurement financed by the German federal state of Bavaria.