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有目的地调节耕地上养分的循环和平衡是增产作物,维持地力的重要措施。 珠江三角洲土地肥沃,解放以后复种指数增加,粮食成倍增产而其肥力变化亦为人所注视,近年已提出种种见解,但缺乏充分的论证根据。为了考察这一问题,我们试通过计算地上主要营养元素氮、磷、钾的收支数量,并加以比较,希望能从一个方面说明地力的变化,为今后建立科学施肥制提供参考。这方面国内外也有类似的做法,为此我们于1978年对珠江三角洲中主要粮产区一中山县进行了调查,并参照有关资料计算该县解放后29年(1949—1977)耕地养分的平衡情况,同时对其中一些问题加以分析讨论。
The purposeful regulation of the circulation and balance of nutrients on cultivated land is an important measure for increasing crops and maintaining fertility. The fertile land in the Pearl River Delta, after the liberation, the index of multiplication increased, the yield of grain doubled and the change of its fertility was also observed. In recent years, various opinions have been put forward, but there is a lack of sufficient justification. In order to examine this issue, we try to calculate the income and expenditure of nitrogen, phosphorus and potassium, and compare them. We hope that we can explain the change of soil fertility from one aspect and provide a reference for establishing a scientific fertilization system in the future. In this regard, there is a similar practice both at home and abroad. To this end, we conducted a survey on Zhongshan County, one of the major grain-growing areas in the Pearl River Delta in 1978 and calculated the balance of arable land for 29 years (1949-1977) after the liberation of the county with reference to relevant data At the same time, some of these issues are analyzed and discussed.