Variable-rate Fertilization And Its Environmental And Economic Benefit In Precision Agriculture

As one of the key content in precision agriculture, variable-rate fertilization is a fixed location, time and quantity fertilization technique according to the spatial and temporal variability of crop and its growth environment by virtue of information technology, to decrease fertilizer consumption with same production, improve cropland eco-environment, increase the fertilizer use efficiency, and obtain maximum environmental and economic benefit.Based on the data of soil nutrients, crop and its yield, and etc., with the mathematical statistics method, such as correlation analysis, principal component and factor analysis, and etc., Decision-Tree-Construction method and GIS map overlay analysis, the variability and its cause of soil nutrient and crop yield were analyzed, the optimum fertilization model for paddy rice in Shanghai and spring wheat in Ningxia was built associated with the field experiment data, and fertilization prescription map was generated from the decision-making platform of precision planting. It was indicated from contrastive analysis that precision fertilization had preferable environmental and economic benefit in decreasing fertilizer consumption and fertilizer loss, and etc.The main research content and primary results are as follows:The technological frame of variable-rate fertilization in precision agriculture was preliminarily established, mainly includes the gathering, analysis and modeling of field experiment data, the generation of fertilization scheme, and the assessment of environmental and economic benefit.Huge spatial variability was among soil nutrients and crop yield. A significant correlation between paddy rice yield and soil nutrients was in Shanghai, and the spatial variability of paddy yield was mainly caused by the spatial discontinuity of soil nutrients. In Ningxia, soil organic matter is the main limiting factor of spring wheat yield.According to the variable-rate fertilization model in precision agriculture, the optimum quantity of applying nitrogenous fertilizer is less than the traditional quantity by 31.5%, with a net increase of economic benefit of 222.0 yuan per hectare. The decrease of applying nitrogenous fertilizer has positive effects in improvement of the rice quality. The optimum quantity of applying nitrogenous fertilizer in spring wheat in Ningxia is less than that in 3 years ago by 10 percent, and the optimum quantity of phosphorus fertilizer is less than that by 15 percent.Variable-rate fertilization could decrease the loss of nitrogenous fertilizer, with a runoff decrease of 11.7%, and a leaching decrease of 10.4%, which is beneficial to the improving of cropland eco-environment.