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随着农村经济体制的改革,上海近年来三熟制种植面积逐年减少,二熟制已恢复为主要种植方式,1985年至今,上海二熟制耕地面积占总耕地面积的85～90％。在肥料管理中,近年来,化学氮肥用量迅速增加,有机肥施用量明显减少,氮磷钾比例失调。在这种肥料结构下,单施化学氮肥或氮、磷、钾配合施用,而不施有机肥,对作物的增产效应及土壤肥力有何影响,这是农业生产中必须研究解决的课题,为解决这一问题,我们从1983年开始进行长期的定位试验。材料与方法试验从1983年单季晚稻开始,在本市青浦县朱
With the reform of the rural economic system, the area of three-cropping system in Shanghai has been decreasing year by year and the second-cropping system has been restored as the main planting mode. Since 1985, the area of second cropping system in Shanghai has accounted for 85-90% of the total cultivated land area. In fertilizer management, in recent years, chemical nitrogen fertilizer increased rapidly, significantly reduced the amount of organic fertilizer, nitrogen, phosphorus and potassium imbalance. In this kind of fertilizer structure, the application of chemical nitrogen fertilizer alone or nitrogen, phosphorus and potassium combined application, without organic fertilizer, the crop yield-increasing effect and soil fertility, which is the agricultural production must be studied to solve the problem for To solve this problem, we have been conducting long-term positioning experiments since 1983. Materials and Methods The experiment began with the single season late rice in 1983 and Zhu in Qingpu County