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白玉兰缺铁症一般从5月上旬开始出现,先是叶片变小,老叶仍保持绿色,新叶叶脉绿色,叶肉变黄甚至变白,若缺铁时间过长,6月下旬叶缘就会干枯,整个叶片逐渐枯萎。由于铁在植物体内活动性很小,老叶中的铁不能向嫩叶转移,因此缺铁时往往是下部叶片仍保持绿色,嫩叶出现黄化,最终导致叶片枯萎,树势衰弱,花芽不能形成,整棵树不能开花。我们采用了三种防治方法。叶面喷肥宜在早晨或傍晚喷施。将0.3%的硫酸亚铁、尿素及磷酸二氢钾等
Magnolia iron deficiency usually start in early May, first leaves smaller, the old leaves remain green, the new leaf veins green, yellow and even yellowish, if the iron deficiency is too long, the leaf margin in late June will be Withered, the entire leaves gradually withered. Due to the low activity of iron in the plants, the iron in the old leaves can not be transferred to the young leaves. Therefore, when the iron is deficient, the lower leaves remain green and the young leaves turn yellow. Eventually, the leaves become wilted, the trees weak and the flower buds can not Formation, the whole tree can not blossom. We used three methods of prevention and treatment. Foliar spray should be sprayed in the morning or evening. 0.3% of ferrous sulfate, urea and potassium dihydrogen phosphate and so on