1. When sowing with water for soil moisture generation: good soil moisture is the guarantee for achieving complete, complete, strong and even seedlings. If the soil moisture is insufficient or uneven for sowing, it is bound to cause seedling shortage and ridge breaking, or uneven seedling size, many weak plants and high rate of empty stems. The suitable soil moisture for corn sowing is 65% to 75% of the field water capacity.
2. After jointing: After jointing, maize plants grow vigorously, male and female ears begin to differentiate, and water demand increases. When jointing, if the soil water content is less than 65% of the field capacity, watering is required. Water saving by watering and pulling is beneficial to the stable growth of stem and leaf, female and floret differentiation, which can reduce the number of empty stems and increase the number of grains per ear.
3. Heading water time: before and after heading and flowering of maize, the leaf area is large, the temperature is high, and the transpiration and evaporation are strong, which is the period when maize needs the most water and is most sensitive to water in its life.
4. Grouting water: during grain filling, more water is still needed. The appropriate soil water content is 70% to 75% of the field capacity, and irrigation is required if it is less than 70%. At this time, irrigation can prevent premature senescence of plants, maintain more green leaves, maintain higher photosynthesis, prolong grain filling time and improve grain filling speed, which is conducive to improving grain weight.