变量施肥对玉米产量及土壤养分影响的试验

采用自主开发设计的基于GPS和GIS技术的自动变量施肥系统，于2003、2004年间进行了玉米种植条件下变量施肥田间试验。与相邻传统施肥地块相比，变量施肥在一定程度上增加了玉米产量，在合理控制化肥用量的情况下，可以达到既减少投入又增加产量的目的。土壤养分分析结果表明：两年试验前后，变量区与传统施肥区土壤中的碱解氮含量均有所增长，但变量区碱解氮含量的变异系数较传统区减少；变量区和传统施肥区速效磷的含量都有所下降，且变量区较传统区下降明显，变异系数减少；速效钾含量均增加，增加幅度基本一致，但变量区变异系数下降。说明变量施肥具有一定均衡土壤养分的作用。

Experimental study on the influence of variable rate fertilization on maize yield and soil nutrients

During 2003 and 2004, the experiments of variable rate fertilization(VRF) for maize were carried out using the VRF system, which was researched and produced by the authors themselves. VRF results in higher maize yield to a certain extent than that of traditional fertilization, and can not only cut down input but also increase output under the condition of reasonable fertilizer application rate. The analysis result of soil nutrients shows that the concentration of available N in variable-rate zone and traditional zone are both increased, but the coefficient of variance in variable-rate zone is lower than that of traditional zone; the concentration of available P in the two zones are both decreased, and the concentration of available P in variable-rate zone is much lower than that in traditional zone, and its coefficient of variance in variable-rate zone is lower too; the concentration of available K in the two zones are both increased to the same degree, however the coefficient of variance in variable-rate zone drops. Experimental results show that VRF produces some function of balancing soil nutrients.