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农作物施用化肥不当或过多,往往会导致作物贪青、徒长、生育期延迟、抗性减弱、易倒状、病虫害加重或烧苗、萎蔫,轻者造成减产、品质下降,重者整株死亡。这种因化肥施用引起的不良现象称为“肥害”。生产上作物产生肥害的原因主要有以下几种:①浓度过高伤害:如一次施用化肥过多或施肥后土壤水分不足,造成土壤内肥料溶液浓度过高,根系的吸水困难,僵苗不发,甚至使作物细胞内水分反渗透,造成作物失水,出现萎蔫,影响正常发育以致枯死。②有害气体毒害:当土壤中有大量的氨或铵离子,一方面以气态形式挥发,遇空气中的雾滴和作物叶片上的水珠而溶解,形成碱雾或碱性小水珠,在叶片上产生焦枯斑点,灼伤作物。如碳酸氢铵,在气温比较高的情况下施用,容易产生大量氨
Improper or excessive use of fertilizers on crops often results in crop greyishness, leggy growth, delayed growth period, weakened resistance, easy to fall, pests and diseases increase or burned seedlings, wilting, light caused by reduced production, quality declines, severe whole plant death . This adverse effect due to fertilizer application is called “fatal”. The main causes of fertilizer production on the crops are the following: ① concentration is too high damage: such as a fertilizer application or excessive soil moisture after fertilization, resulting in the soil fertilizer solution concentration is too high, the root of the water-absorbing difficulties, stiff seedlings do not Hair, and even the water inside the crop cells reverse osmosis, resulting in crop water loss, wilting, affecting the normal development and thus dead. ② toxic gas poisoning: When the soil has a large number of ammonia or ammonium ions, on the one hand volatile in the form of gas, the case of droplets in the air and water droplets on the leaves to dissolve the formation of alkali fog or alkaline water droplets in the Scorch spots on the leaves, burns crops. Such as ammonium bicarbonate, in the case of relatively high temperatures, easy to produce large amounts of ammonia