Nitrogen deficiency: initially appeared on new shoots and old leaves of apple trees. The new shoots were short and fine, and the leaves were small. After the shoots were wooded, they turned reddish-brown. The leaves of the base of the shoots are yellowed and gradually develop towards the top of shoots, causing the young leaves of the shoots to turn yellow, and even causing fallen leaves and physiological fruit drop. Control methods: timely topdressing urea, ammonium nitrate and other nitrogen fertilizers. Phosphorus-deficient disease: The leaves are small and thin, the branches and leaves are gray-green, the petioles and the veins on the back are purple, the flowering leaves are delayed, and the new branches have fewer fine branches. When phosphorus is severely depleted, the old leaves turn into yellow-green and dark-green mosaics. Control methods: After leaf spreading, 0.5%~1% superphosphate was sprayed on leaves; phosphate fertilizer particles were applied on the root distribution layer. Deficiency of potassium: leaf spots and leaf margins often occur as early as purple and then brown spots, leaf tissue near the spot is still growing, causing the leaves to shrink. When the potassium deficiency is severe, the entire leaf is scorched, but it does not fall off. Small flower buds, small and light fruit coloring area. Control methods: topdressing plant ash, potassium dihydrogen phosphate, potash potassium fertilizer, foliar topdressing concentration of grass ash is 3% to 10% of the leachate, the other is 0.5% to 1%. Pet Massager,Cat Massage,Dog Massage,Pet Groomer Tools Shenzhen Jie Zhong Lian Investment Co., Ltd. , https://www.szmeizons.com
The Symptoms and Prevention of Nitrogen, Phosphorus and Potassium Deficiency in Apple Trees