If the apple tree grows weakly, the branches and leaves grow slowly, and the leaves turn yellow or yellowish, this indicates that the fruit trees lack oxygen and iron deficiency, and the spraying of nitrogen fertilizer should be the main method, and some ferric citrate and phosphorus and potassium fertilizers should be sprayed properly; if the leaves are bright green The section between branches is too long and nitrogen fertilizer is sufficient. Phosphate fertilizer and potash fertilizer should be sprayed, and some trace elements should be sprayed properly. 1. Pay attention to the spraying time in the early flowering period, flowering period, strong fruit period on cloudy days or sunny days after 5 pm. The interval is 10 to 15 days. 2. It should be noted that the carbonamine in fertilizer N fertilizer and the phosphate rock powder in P fertilizer are ineffective or harmful to the foliar spray and should not be sprayed. Suitable varieties are urea, superphosphate, potassium dihydrogen phosphate, potassium sulfate, ash and trace elements in the borax, zinc sulfate, manganese sulfate, iron sulfate, iron citrate and so on. 3. To distinguish between the primary and secondary foliar spray fertilizer is not the main mode of fertilization, but only in the case of insufficient fertilization of the soil used in a way of assisted fertilization. 4. It is necessary to pay attention to spraying concentration of urea 0.3% ~ 0.5%, superphosphate 0.5% ~ 1.2%, potassium dihydrogen phosphate 0.2% ~ 0.4%, ternary compound fertilizer 0.4% ~ 0.5%, plant ash 1.5% ~ 2%, The concentration of borax, zinc sulfate, iron citrate, magnesium sulfate, etc. in the trace elements is 0.08% to 0.15%. Canned Tuna,Fresh Canned Tuna,Frozen Canned Tuna,Canned Skipjack Chunk ZHEJIANG RETRONX FOODSTUFF INDUSTRY CO.,LTD , https://www.retronxfoods.com