Effect of dry sowing Wet Water output on Cotton

In recent years, with the large-scale popularization of conventional drip irrigation, drip emergence of cotton after sowing has become a conventional technique, which has been adopted by most cotton planting areas. Dripping water at an appropriate time can not only avoid the final frost in April, but also the emergence of cotton seedlings is neat and consistent, the growth potential is better, and it is convenient for field management. However, the amount of water dripping out of seedling water varies from place to place.

Our region is a sub-suitable cotton area, there are more cold weather in spring every year, the final frost is mostly around April 20, and the temperature of cotton seedling stage is lower. The incidence of cotton root rot is more serious in cold weather-prone years. As the disease of cotton root rot is aggravated under the conditions of low temperature and high humidity, the method of light dripping seedling water is adopted in most areas. the amount of dripping water is 1520 cubic meters per 667 square meters, which can basically meet the emergence of cotton seedlings and help to reduce the humidity in the field. it is more beneficial to the rise of ground temperature, and the incidence of root rot is relatively mild. Through years of comparative observation, this dripping seedling emergence method has many disadvantages, and changing to Dashui prescription one-time foot dripping is more beneficial to the high yield of cotton.

1. Distribution of different dripping water in soil.

Through observation for many years, the wettability of soils with different dripping volume is different. When the amount of water is small, the distribution of water in the soil is in the shape of "V", and the water is mostly distributed in the upper part of the plough layer, which has little effect on seedling emergence. However, because the water is mainly in the upper part and the bottom is insufficient, the root system of cotton is shallow, and the drought resistance is poor, so the water can not be stopped after emergence. On the other hand, in the strip field with large amount of water dripping at one time, the distribution of water in the soil is in the shape of "U", and the water is distributed in the whole plough layer, which is very beneficial to the root system of cotton.

Second, the influence of different dripping water on ground temperature.

Different amount of water has different effects on ground temperature. Although the effect of small amount of water dripping on ground temperature was less than that of large amount of water, it had little effect on the growth of cotton seedlings. Large amount of water is carried out in the early stage, and there is only one bad stimulation, and this is also the time when the seed coating agent has the best effect. While the small amount of dripping water gives cotton seedlings a low temperature and high humidity environment before the temperature rises, the effect of seed coating agent has passed, and the occurrence of root rot will be aggravated, which is not conducive to the growth of cotton seedlings.

Third, the effect of different dripping water on planting measures.

The current planting mode is "short, dense, early, plastic film, uniform". In the period of squatting seedlings and preventing premature senility in the middle and later stage, the application of different dripping water will produce different effects. The strip fields with a small amount of water can only keep dripping, and the delay in entering the head water makes it impossible to squat seedlings. Squatting seedlings of cotton is the best way to promote root rooting, which can prevent premature senescence in the middle and later stage. At the same time, squatting seedlings also make use of the over-compensation effect formed by appropriate water shortage of cotton to promote the transformation of cotton growth period in advance, which is conducive to the formation of high-yield shelves. In our region, there is a period of shortage of water resources every year, and the irrigation cycle will be lengthened, which has a great impact on the yield of cotton plants with shallow roots.

4. Effects of different dripping water on cotton physiology.

Cotton has little demand for nutrition before reproductive growth, especially for nitrogen fertilizer. In the vegetative growth period, if the amount of nitrogen fertilizer is too much, the activity of nitrate reductase in cotton plant will be enhanced, and the vegetative growth of cotton plant will be prosperous and the reproductive growth will be delayed. At the same time, due to the consumption of a large amount of soluble sugar, the content of soluble sugar in buds and young bolls was insufficient, resulting in a large number of falling buds, flowers and young bolls. Therefore, it is not recommended to apply a large amount of fertilizer, especially nitrogen fertilizer, before flowering. However, continuous small amount of water dripping affects the whole layer fertilization, which has a great influence on cotton plants, and there is a great difference in the utilization of deep fertilizer.

Years of observation shows that the one-time large water prescription has more advantages than the small water square. Some places also use dripping seedling water to use a small amount of dripping, and so on after the emergence of enough water, in order to facilitate later squatting seedlings, but the overall effect is not as good as one-time dripping. Author's unit: Shihezi 149th regiment