Make a good job of planting cotton this winter and next year

Many cotton farmers do not pay attention to cotton field winter management, accustomed to spring ploughing before spring sowing, spring irrigation. In fact,"good winter soil, good cotton planting next year; good winter irrigation, cotton planting effortless; winter tillage plus winter irrigation, less insects and high cotton yield" has become an important experience in cotton production. For this reason, in winter, cotton farmers should do a good job of the following:

Deep ploughing in winter can not only turn out part of raw soil, bury weeds and crop residues on the ground, but also improve the ability of storing rain and snow. After full weathering in winter and spring, the soil matures into a deep and loose living soil layer, creating good environmental conditions for cotton root development and microbial activities. Meanwhile, winter is the weakest period for cotton bollworm survival, and winter tillage can deteriorate the places where pests overwinter. It was observed that adults could not emerge in the soil layer below 10 cm. Winter ploughing depth is generally about 20 cm. In this way, winter tillage can turn most of the pupae into deep soil, so that the second year can not emerge. Winter tillage can also be part of the insect pupae out of the ground and frozen to death or pecked by natural enemies.

Harrowing in winter harrows the land roughly before ploughing in winter, and harrows out larger crops after ploughing. In this way, water can be stored to preserve soil moisture, and some overwintering insects and pupae can be harrowed to death. Cotton bollworm pupae overwinter in the soil, underground depth does not exceed 10 cm, with more than 6 cm in the topsoil. According to investigation, winter harrowing in cotton field can kill about 80% of cotton bollworm pupae.

Fertilization in winter can be carried out at the same time as winter ploughing. Generally, 3~4 cubic meters of high-quality farm manure, 8~10 kg of pure nitrogen and 7~8 kg of phosphorus pentoxide are applied per mu to promote the decomposition and ripening of organic matter.

Winter irrigation followed by winter ploughing can not only solve the contradiction between grain and cotton competing for water in the following spring, but also increase the mortality of overwintering pupae. At the same time, the fertilizer nutrients can be infiltrated into the deep soil along with water to adapt to the distribution level of cotton roots, so as to optimize the distribution of nutrients and facilitate the absorption of cotton plants. Winter irrigation should be uniform, sufficient, transparent for the principle, water is not too large, time to day and night freezing is appropriate. After thawing in early spring, it is necessary to loosen the soil in time to improve the ground temperature and maintain soil moisture, so as to ensure the quality of soil preparation.

The results showed that when the relative soil moisture content was 40%, the mortality of cotton bollworm pupae was 46.7%, the adult emergence rate was 33.3%, and when the soil moisture content reached saturation, the mortality of pupae was 100%. Other data show that the overwintering mortality rate of cotton bollworm pupae is about 80% in the plots cultivated in winter and irrigated in winter, 60~70% in the plots cultivated only without irrigation, and only 30~40% in the plots without cultivation without irrigation. Therefore, the prevention and control of overwintering period and the reduction of overwintering base can have twice the result with half the effort to control the occurrence of cotton bollworm in the second year.