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目前,农业上施用的化肥主要是氮(N)、磷(P)、钾(K)三种,它们都是农作物必不可少的要素。一般土壤里这三种元素的含量不能满足植物生长的需要,其余30种微量元素如铁、铜、锌、镁等都可由土壤供给。化肥的大量施用,虽然提高了农作物的产量,但由于施用量不当以及施肥不合理,常使很多化肥浪费掉,而且随水土流失进入水体,从而加剧了环境污染,导致生态系统多方面失调。
At present, the main fertilizer used in agriculture is mainly nitrogen (N), phosphorus (P) and potassium (K), all of which are essential elements of crops. In general, the content of these three elements in the soil can not meet the needs of plant growth. The remaining 30 kinds of trace elements such as iron, copper, zinc and magnesium can be supplied from the soil. Although large-scale application of chemical fertilizers has increased crop yields, many chemical fertilizers are often wasted due to inappropriate application rates and irrational fertilization, and water and soil erosion have been exacerbated by water and soil erosion, leading to various aspects of ecosystem disruption.