Why is summer corn yellow?

Why do summer corn have yellow leaves? Is there any way to fix it? Please guide the yellow and dull leaves of corn, which is caused by the lack of nitrogen in corn and soil, or caused by diseases and insect pests. The yellowing of maize leaves for a long time often leads to early reproductive growth, premature heading, baldness and "premature senility" of maize plants, that is, maize plants age and mature prematurely and the yield is low. The measures to control yellow leaves of maize are as follows: re-application of fertilizer and water to yellow-leaf corn is managed by "five-stage topdressing", that is, topdressing seedling fertilizer, small trumpet mouth fertilizer, big trumpet mouth fertilizer, ear fertilizer, grain fertilizer, fertilization for a small number of times, in order to improve fertilizer efficiency. Urea 10 kg, potassium sulfate 5 kg per mu in seedling stage, diammonium phosphate 15 kg, potassium sulfate 10 kg, total micro-fertilizer 2 kg in small trumpet stage, diammonium phosphate 25 kg, potassium sulfate 15 kg, total micro-fertilizer 3 kg per mu in big trumpet stage, diammonium phosphate 10 kg, potassium sulfate 5 kg in ear stage, diammonium phosphate 2 kg and potassium sulfate 3 kg in grain stage. If it does not rain after fertilization, it must be watered 5 days after fertilization, adjust fertilizer with water, and promote fertilizer with water. Early disease prevention and skillful pest control according to the characteristics of yellow leaf disease and insect occurrence, early application of medicine can get rid of the disease (insect) without leaving the disease. Click to get more corn planting techniques click to get more food crop planting techniques