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水稻是宁夏引黄灌区主要作物之一。近几年来,在三大革命运动推动下,广大贫下中农战天斗地,广开肥源,在有机肥料为主的前提下,逐年增施化肥,对于水稻大面积均衡增产起了重要作用。但是,在生产实践中注意到,计算作物达到某一产量水平所需用肥量时,往往要比作物养分实际需要量大一倍左右。这是因为作物对土壤养分的利用,实际上只是一部分,而不是全部被吸收。据测定,氮利用30～50％,磷10～25％,钾30～60％。大体说来,只利用了一半左右。以水田施用氮素化肥为例:以往的习惯用法是撒在表层。研究表明:水田土壤表层是氧化层。在好气状态下,由于硝化细菌的活动,铵态氮被转化为硝态氮,随灌溉水的移动而淋
Rice is one of the main crops in the irrigation area of Yellow River in Ningxia. In recent years, under the impetus of the three major revolutionary campaigns, the vast majority of poor peasants and peasants have played an active role in fighting the flames of the sky and have opened up the source of fertilizers. Under the premise of organic fertilizers, increasing fertilizers year by year has played an important role in the balanced increase of rice production. However, it is noted in production practice that the amount of fertilizer required to achieve a given crop yield is often about twice as large as the actual crop nutrient requirement. This is because the use of crop nutrients in the soil is actually only a part, but not all of them are absorbed. It has been determined that 30-50% of nitrogen is used, 10-25% of phosphorus, and 30-60% of potassium. In general, only about half are used. Take the paddy field to apply nitrogenous fertilizer as an example: the past customary usage is spreading on the surface. Studies have shown that paddy soil surface is an oxide layer. Under aerobic conditions, ammonium nitrogen is converted to nitrate nitrogen due to the activity of nitrifying bacteria. With the movement of irrigation water,