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固原县属黄土高原半干旱地区,是水土流失重点县之一。年平均降水量350—550毫米之间,多年(1949—1979年)平均每公顷单产为573.75公斤,降水资源没有得到充分利用。就投肥量来看,在1980年以前,全县平均每公顷投入氮素只有22.5公斤(包括少量化肥在内),按40%的利用率计算,也仅能生产300来公斤粮食。那么,多余的273.75公斤粮食所带走的养分,主要来自土壤的释放。长此下去,土壤肥力水平将逐年下降,粮食单产会低而不稳。为了改变这种局面,必须从调整农田结构入手,改单一的粮食生产为农牧结合的种植制度,改广种薄收为集约经营。在变革种植制度的同时,增施化肥和合理施肥就成为退耕种草和提高单产同步进行的关键措施之一。为此,我们就施肥技术——化肥合理深施、肥料组合、肥料配比等方面进行了试验研究。
Guyuan county belongs to the semi-arid area of the Loess Plateau and is one of the key counties for soil and water loss. The annual average precipitation is between 350 and 550 millimeters. For many years (1949-1979), the average yield per hectare is 573.75 kilograms, and precipitation resources are not fully utilized. In terms of fertilizer input, before 1980, the average input of nitrogen per hectare in the county was only 22.5 kg (including a small amount of fertilizers), and at 40% utilization, only 300 kilograms of grain could be produced. Well, the extra 273.75 kilograms of food brought nutrients, mainly from the release of soil. If the situation continues, soil fertility will decline year by year, and grain yields will be low and unstable. In order to change this situation, we must start with adjusting the structure of farmland and change the single grain production system into a farming and animal husbandry combination system. At the same time of reforming the planting system, increasing chemical fertilizers and applying fertilizers have become one of the key measures for the simultaneous retirement cultivation and improvement of yield. To this end, we conducted a pilot study on fertilization techniques - rational application of fertilizer, fertilizer combinations, fertilizer ratio and so on.