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一、什么是“V”字理论稻作法? 据日本试验,水稻抽穗前33天,正是幼穗分化的始期。以幼穗分化期为中心的前后12天这段时间(亦即抽穗前45天至21天),大量施用氮素最危险,籽粒成熟率最低。而在此时期之前和之后,相距时间越长,施用氮肥后成熟率越高。如以曲线图表示,籽粒成熟率的高低变化呈“V”字型,根据这种理论进行水稻施肥管理的方法,日本人叫做“V”字理论稻作法。二、幼穗分化期追施氮素降低成熟率的原因: 一般说来,要使每10公亩产量提高到700公斤(每亩934斤),每平方米的叶片面积应达到5—10平方米,
First, what is the “V” theory of rice practices? According to Japanese tests, 33 days before rice heading, it is the beginning of panicle differentiation. During the period of 12 days before and after the panicle differentiation (ie, 45 days to 21 days before heading), nitrogen application was the most dangerous and the grain maturity was the lowest. However, before and after this period, the longer the distance, the higher the maturity rate after applying nitrogen fertilizer. As shown in the graph, the grain ripening rate changes in the “V” shape, according to this theory of rice fertilization management methods, the Japanese call “V” theory of rice practices. Second, the ear differentiation period Nitrogen top down rate of maturity reasons: In general, to make every 10 acres of yield increased to 700 kg (934 kg per mu), leaf area per square meter should reach 5-10 square feet Meter,