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近年来,世界各国的氮肥施用量迅速增加,而植物对氮肥的利用率只有25—50％,大部分的氮肥白白浪费掉。这不仅造成经济上的损失,而且又污染了环境,直接影响人体健康,甚至给植物生长和发育带来了不良影响。因此各国对植物吸收利用氮肥的规律及特点进行了大量的研究工作,以寻求提高氮肥利用率的合理施肥途径。本试验是利用同位素~(15)N研究苹果树吸收氮肥的规律和特点,特别是研究不同时期施用氮肥对苹果树利用和分配氮素的影响,为寻求适宜的氮肥施用时期提供依据。
In recent years, the amount of nitrogen fertilizer used in various countries in the world has rapidly increased, while plants use only 25-50% of nitrogen, most of which is wasted. This not only causes economic losses, but also pollutes the environment, directly affects human health and even has an adverse impact on plant growth and development. Therefore, various countries carried out a large amount of research work on the regularities and characteristics of plants absorbing and utilizing nitrogen fertilizer in order to seek a reasonable fertilization way to improve the utilization rate of nitrogen fertilizer. In this experiment, we used isotopes (15) N to study the rules and characteristics of nitrogen absorption of apple trees. In particular, the effects of applying nitrogen fertilizers on the utilization and distribution of nitrogen in apple trees in different periods were studied to provide evidences for the suitable application period of nitrogen fertilizer.