To irrigate the crops or not to irrigate the crops, corn should be watered four times for high yield.

"irrigate, not irrigate, look at the world of crops." Whether corn needs watering or not depends on the growth and development of corn, weather and soil water content. If the soil water content is less than 16%, the clay water content is less than 20%, and the sand water content is less than 12%, irrigation is needed. From the point of view of the development of maize and the period of great influence on yield, the key water should be irrigated for 4 times.

Watering corn

The main results are as follows: (1) when sowing with soil moisture, good soil moisture is the guarantee of seedling integrity, seedling integrity, seedling strength and seedling uniformity. If the soil moisture is insufficient or uneven sowing, it is bound to cause lack of seedlings and broken ridges, or uneven seedling size, many weak plants and high empty culm rate, so it is impossible for such a population to obtain high yield. The suitable soil moisture for corn sowing is between 65% and ∼ 75% of the field capacity. When sowing, if the soil water content is less than 65% of the field capacity, it must be sown after sowing, and summer corn can also be sown with "head covered water" after sowing. In spring corn area, it is best to carry out winter irrigation and timely preservation of soil moisture in early spring. Winter irrigation should be thoroughly watered. Summer sowing or interplanting corn can be combined with watering wheat yellow water. The amount of irrigation is generally 50 ∼ 60 cubic meters per mu. If you water "covered head" water, generally water 40 ∼ 50 cubic meters per mu.

(2) jointing water: the maize seedling plant is small, resistant to drought and afraid of waterlogging, and the suitable soil moisture is between 60% and 65% of the field capacity. In general, there can be no watering. However, after jointing, the plant grows vigorously, the male and female ears begin to differentiate, and the water demand increases. If the soil water content is less than 65% of the field capacity, it should be watered, generally about 55 cubic meters per mu. Watering and saving water is conducive to stem, leaf and female growth and floret differentiation, can reduce empty culms and increase the number of grains per ear. For example, in the high-yielding spring corn fields of Yanqing County and Huairou County in Beijing, the average number of grains per ear irrigated and water-saving increased by 51.6 grains (by 11%), and the number of ears per mu increased by 3.8%.

(3) before and after the heading and flowering stage, the leaf area is large, the temperature is high, and the transpiration is exuberant, which is the period when the corn needs the most water and is most sensitive to water. At this time, the suitable soil water content is 70% ∼ 80% of the field capacity, less than 70% should be watered, 55 ∼ 60 cubic meters per mu. At this time, irrigation can improve the vitality of maize pollen and filaments, which is beneficial to pollination and grain setting, prolong the functional period of leaves, improve photosynthetic capacity and increase dry matter production. It is beneficial to grain filling, reduce grain abortion, increase the number of stable grains and increase 1000-grain weight. Irrigation and heading water must be timely, full, can not wait for the day to rely on the rain, if found that the leaves wilted and then irrigated it is too late. According to the experiment, if the leaves wilt for 1 ∼ and then irrigate for 2 days due to short-term drought before and after heading, the yield will also be reduced by 20%.

(4) more water is still needed during grain filling. The suitable soil water content is 70% ∼ 75% of the field capacity, less than 70% should be irrigated, usually about 55 cubic meters per mu. Irrigation at this time. It can prevent premature senescence of maize, maintain more green leaves, maintain higher photosynthesis, prolong grain filling time and improve grain filling speed, and help to increase grain weight.