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甘薯的根系深而广,茎蔓又能着生地生根,吸肥力很强,所以耐旱耐瘠。实践证明,甘薯对氮、磷、钾三要素的需求量,以钾最多、氮次之、磷又次之,生长过程中所需氮、磷、钾三要素的比例一般为1:1:2.5。但三要素的功能各不相同,不可相互代替。一、三要素的功能及缺素症状1.氮是蛋白质的重要组成部分,若氮素供应不足,则老叶首先呈现缺绿,叶片数、分枝数减少,叶片缩小,节间缩短,叶片容易发黄早衰,进一步发展为老叶脱落,光合效能降低,严重影响产量。2.磷是甘薯细胞的重要组成部分,能促使根系发
Roots of sweet potato deep and wide, stems and roots can take root, absorption of fertility is strong, so drought and barren. Practice has proved that sweet potato nitrogen, phosphorus and potassium demand for three elements, the most potassium, followed by nitrogen, followed by phosphorus, nitrogen, phosphorus and potassium required for the growth of the proportion of the three elements is generally 1: 1: 2.5 . However, the three elements have different functions and can not be replaced by each other. First, the three elements of the function and the lack of symptoms 1. Nitrogen is an important part of the protein, if the nitrogen supply is insufficient, the old leaves first showed lack of green, the number of leaves, the number of branches reduced, leaves reduced, internodes shortened, leaves Easy to yellow premature aging, further development of old leaves fall, photosynthetic efficiency decreased, seriously affecting the yield. Phosphorus is an important part of sweet potato cells, can promote root hair