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施肥是栽培措施的中心环节。如何经济用肥达到高产,是当前重要的课题。氮是一般土壤最缺乏而作物最需要的营养元素,氮肥施用合理与否,对产量有重大影响。华二大队采用卷秧育苗栽培晚熟高产品种京引39,插秧密度每亩3.5～4万穴,20～28万苗,土壤肥力中上等(表1)。现将合理施用氮肥的几个问题,分析讨论如下。施用量氮肥的适宜用量,是合理施用氮肥的关键问题。某一品种需要多少氮,这固然由品种特性所决定,但因地力、密度等因素的影响,实际施用量是各不相同的。华二大队地处黄河岸边,大部分为淤灌土,土层约70～100厘米为黄土,下为细沙,地下水位较低,土壤渗水性良好。由于连年重视大面积均衡施用农家肥,地力普遍显著上升,大部分基本农田具有中上等肥力水平,自然生产力水稻亩产可达700斤左右。每年种植水稻4000
Fertilization is the central part of cultivation measures. How to achieve high output with economic fertilizer is an important issue at present. Nitrogen is the most common lack of nutrients in general and crop nutrients, nitrogen fertilizer is reasonable or not, have a significant impact on the yield. Hua second brigade using curly seedling cultivation of late varieties of high-yielding Beijing cited 39, transplanting density of 3.5 to 40,000 acre per mu, 20 to 280,000 seedlings, soil fertility in the upper (Table 1). Several issues of rational application of nitrogen fertilizer will now be analyzed and discussed as follows. Appropriate amount of nitrogen fertilizer application, is the key issue of rational use of nitrogen fertilizer. The amount of nitrogen required for a particular species depends, of course, on the characteristics of the variety, but the actual application rates vary depending on such factors as geotechnical and density factors. The second brigade is located on the shores of the Yellow River, mostly silt soil. The soil layer is about 70-100 cm loess, and the lower is fine sand. The groundwater level is low and the soil seepage is good. Since year after year emphasis on large-scale balanced application of manure, soil fertility generally increased significantly, most of the basic farmland with the best fertility level, natural productivity of rice yield of about 700 pounds. Grow rice 4000 each year