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水稻旱育秧田的黄化苗,是一种秧苗生理障碍性病害,在三叶期以后,秧苗由自养生长转入异养生长阶段时,黄化苗开始发生。发病症状为:由第四片叶始,心叶发白,老叶变黄,呈明显的黄白叶,直到全株变黄枯死。一、黄化苗的发生原因1.土壤贫瘠,理化性状不良,全盐含量在0.2%以上,土壤 PH 值7以上,容易发生黄化苗。2.土壤有机质含量低,或施用有机肥的质量较差;在土壤 PH 值较高时,秧田施用磷肥过量,使活性铁((Fe~+)~+)与磷结合而被固定,失去活化作用,致使光合作用降低,形成黄化苗。
The yellow seedlings of rice seedling in dry land are the physiological obstacle of seedling. After the three-leaf stage, the seedlings begin to change from autotrophic growth to heterotrophic growth stage. Symptoms are: the beginning of the fourth leaf, pale heart leaves, the old leaves turn yellow, yellowish white leaves were obvious until the whole plant turn yellow dead. First, the causes of yellow seedlings 1. Soil barren, poor physical and chemical properties, the whole salt content of 0.2% or more, soil PH value of 7 or more, prone to yellow seedlings. 2. The content of soil organic matter is low, or the quality of organic manure is poor. When the soil pH is high, excess phosphorus fertilizer is applied to the seedling so that the active iron ((Fe ~ +) ~ +) is fixed and combined with phosphorus, Role, resulting in reduced photosynthesis, the formation of yellow seedlings.