EVALUATING N_2O-SIMULATIONS OF THE DNDC MODEL WITH MEASUREMENT DATA FOR GIS-BASED REGIONALIZATION

摘要

The Sino-German Project between the China Agricultural University and the University of Hohenheim, Germany, focused on sustainable Agriculture in the North China Plain (www.uni-hohenheim.de/chinaproject). One major focus of the project was the establishment of an experiment field near Beijing to investigate different agricultural practices and their impact on yield and environment. Researchers from several departments were involved in the project: Agricultural Economics, Agricultural Informatics, Vegetable Science, Landscape Ecology, Phytomedicine, Plant Nutrition, Plant Production and Soil Science. The second task was to set-up a GIS based Agricultural Environmental Information System (AEIS) for the North China Plain (NCP), which exceeds almost the size of Germany. The major aim of the AEIS for the NCP is to provide information (ⅰ) about agriculture in the region, (ⅱ) about the impact of agricultural practices on the environment and (ⅲ) of simulation scenarios for sustainable strategies. Consequently, the AEIS for the NCP provides information for decision support and therefore could be regarded as a Decision Support System (DSS), too. In this contribution, the focus is on the importance of the evaluation of simulation models, here the process-based DNDC model for N_2O-simulations. It is possible to interface models and GIS for regional modeling. But in most cases, the availability of detailed measurement data for model evaluation and calibration is not available and therefore, regional applications are restricted. By using daily multi-seasonal measurement data of N_2O-fluxes from maize/wheat rotation nearby Beijing, it is possible (ⅰ) to evaluate model simulations, (ⅱ) to calibrate the DNDC model, and (ⅲ) to apply regional GIS-interfaced N_2O-simulations. With the database of the AEIS for the Beijing Municipality, it is possible to estimate the N_2O emission from winter wheat/summer maize rotation which is the dominant crop rotation in the North China Plain.