微量元素铁、锌、硼是果树正常生长发育所必需的营养元素。生产中出现果树发生铁、锌、硼等微量元素缺乏症,不是土壤中微量元素含量太少,而是土壤中微量元素有效含量低,不能满足果树的需要。影响土壤中微量元素的有效性的重要因子是土壤PH值。铁、锌、硼的有效性常随土壤PH值的升高而降低。因此,微量元素铁、锌、硼的缺乏症多发生于种植在石灰性土壤中的果树。果树缺铁时,果树叶片变黄失绿,光合强度降低,树势衰弱,花芽分化不良,座果下降,甚至绝 Trace elements iron, zinc, boron is the normal growth and development of fruit trees necessary nutrients. Production of fruit trees occur iron, zinc, boron and other trace element deficiency, not the soil trace elements too little, but the effective content of trace elements in the soil is low, can not meet the needs of fruit trees. An important factor affecting the effectiveness of trace elements in soil is soil pH. Iron, zinc, boron effectiveness often with the soil pH value decreases. Therefore, the lack of trace elements iron, zinc, boron occur in the calcareous soil in the fruit trees. Fruit tree iron deficiency, the fruit leaves turn yellow and green loss, reduced photosynthetic intensity, tree weakness, poor flower bud differentiation, fruit decreased, or even