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生态学报 2002
A GIS-based Simulation of Crop Potential Productivity in Hilly Loess Region
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Abstract:
We select the Langwogou catchment in hilly Loess region as the study area, and use a crop productivity model to investigate the spatial variability of crop productivity. Firstly, the YIELD model, including origin of the model, input files and basic parameters, sub model of calculating crop productivity and flow chart, is briefly described. Secondly, crop potential productivity of the catchment was modeled by integrating Geographic Information System with the YIELD model, and the effects of the type of crop, land type, cultivation practice and climatic condition on crop productivity of the catchment were analyzed. The results showed that the simulated yield is in agreement with observed yield for different crops. For different land types, soil water and nutrient levels is much better in bottom land than that in terrace and slope land, resulting in that the simulated yield in bottom land being higher than that in terrace and slope land, but the difference of simulated yield between different land type is not so obvious as that of observed yield. The cultivation practice is a means of enhancing crop yield, and the simulated yields for different cultivation practices, including plastic cover, terrace and fertilization, indicated that cultivation practices can effectively enhance crop productivity, and the average yield increase of three cultivation practices are more than 85%, especially for fertilization, whose improvement rate reaches 95%. This is in agreement with observed yield. The climatic condition is one of the most significant factors affecting crop growth, and the simulated result shows that the model is sensitive to climatic condition, such as precipitation and temperature. The annual variations of rainfall and temperature can result in different crop productivities. It can be concluded from this study that the YIELD model can be effectively used to model the crop potential productivity in Hilly Loess region.