Long-term Field Experiments in Germany: Classification and spatial Representation
Abstract. The collective analysis of long-term field experiments (LTFE) can be used for detecting changes in soil properties and yield such as induced by climate change. However, information about existing LTFEs is scattered, and the research data are not easily accessible. In this study, meta-information on LTFEs in Germany is compiled and their spatial representation is analysed. The study is conducted within the framework of the BonaRes project, which, inter alia, has established a central access point for LTFE information and research data. A total of 205 LTFEs is identified with a minimum duration of twenty years and research in the context of soil and yield. Of these, 140 LTFEs are ongoing. LTFEs are categorized into fertilization, tillage, and crop rotation experiments. The spatial representation is analysed according to the climatic water balance (CWB) and the Müncheberger Soil Quality Rating (MSQR). The results show that, in general, the LTFEs well represent the area shares of both the CWB and the MSQR classes. 89 % of the arable land and 65 % of the grassland in Germany is covered by the three driest CWB classes, hosting 89 % and 71 % of the arable and grassland LTFE, respectively. LTFE cover all six MSQR classes, however with a bias towards the high and very high soil quality classes. The results confirm the very high potential of LTFE data for spatially differentiated analyses and modelling. However, reuse is restricted by the difficult access to LTFE research data. The common database is an important step in overcoming this restriction.