During the sowing period of cotton, it is important to control the following three key technologies, which are crucial to the overall management, yield, quality and profitability:

1. Safely apply pre-emergence herbicides without phytotoxicity. It is understood that the most widely used pre-emergence herbicide for cotton is fleuryl. The residual period of the drug in the soil is long. If it is applied year after year, the residual amount will increase year by year, especially when it is used in sandy land, it will affect the normal growth of cotton root system. I have seen many cotton plants that have been treated with trifluralin for successive years. More than half of the main roots are inhibited and cannot be stretched deep. If they are severely deformed, they will weaken the support function and important absorption function of the root system. If you continue to apply, it will be more serious. In comparison, the application of pendimethalin is safer and has a wider herbicidal range. The safe dosage of pendimethalin in cotton fields is 150-200 ml per mu (33% emulsifiable concentrate), and the lowest dosage is suitable for sandy land. Use caution when spraying under the film. If the soil is too shallow, spraying on the seeds will cause medicinal damage.

2. Design the density and line spacing to adapt it to the ground force and the weather. The principles of design density and row spacing are: the varieties with long growth period and large plant type are planted on the strong ground, the density should be smaller, and the row spacing should be larger, to ensure ventilation and light transmission, to prevent longness and canopy; the growth period is shorter 1. Varieties with smaller plant types are planted on weak ground, the density should be larger, and the line spacing should be smaller, in order to make full use of the land and give full play to the advantages of the group. The current large and small planting model in the northern cotton area has taken into account the advantages of groups and individuals, which is convenient for field operations and is conducive to the normal growth of cotton plants. There are still irreplaceable advantages. According to the survey, the current density of acres is 4,000 to 5,000, and those with a large row distance of 80 to 90 centimeters are mostly. According to the new situation of cotton field fertility level rising in recent years and frequent occurrence of extreme bad weather, the author gives the following design schemes: (1) Medium soil fertility, large row spacing 80-90 cm, small row spacing 50 cm, plant spacing 20 cm, mu 4700 acres ～ 5100 strains, mainly controlled by Azalea under 100 cm in height, 11.5 ～ 12.5 effective bolls per plant, 60,000 effective bolls per mu, and stable yield of about 300 kg per mu (seed cotton, the same below). (2) Poor fertility with 1 water condition, large row spacing 70 cm, small row spacing 50 cm, plant spacing 20 cm, 5555 plants per mu, 10.8 effective bells per plant, by taking advantage of the group, effective bells per mu can reach 6 Ten thousand, 300 kg per mu. (3) In dry and thin land without watering conditions, the plant spacing is 18 cm, 6200 plants per mu, 8 bolls per plant, 50,000 effective bolls per mu, and stable output of about 250 kg. (4) The middle and upper tiers of strong land, with a large row spacing of 90 cm, a small row spacing of 50 cm, and a plant spacing of 27 cm, with an acre of not less than 3,500 plants, and comprehensive control measures to control the plant type, plant height 100 to 110 cm, effective per plant There are 17 bells, 60,000 effective bells per mu, and a stable output of 300 kg. At the same time, large plant type varieties with long growth periods are not needed, so as to prevent the risk of production reduction and quality deterioration caused by late maturity.

3. Apply a good base fertilizer and lay a solid foundation for lowering investment and increasing income. Fertilizer input accounts for about 1/4 to 1/3 of the total cotton field input, and is closely related to the stable cotton production and income. Therefore, the application of base fertilizer during the sowing period not only meets the needs of stabilizing production and increasing income, but also does not waste fertilizer, helping to achieve the goal of zero growth of chemical fertilizer. The recommendations are as follows: (1) Stable production of 300 kg of continuous cropping cotton fields at moderate land. Apply 10 kilograms of diammonium per mu and 10 to 15 kilograms of potassium sulfate per mu. (2) The new stubble field is cotton seedlings with strong growth, no base fertilizer is required, and the supplementary application plan is determined after watching the growth of cotton seedlings. (3) In regions where the "15-15-15" (nitrogen-phosphorus-potassium, the same below) 50 kg of ternary compound fertilizer is used as the base fertilizer for successive years (does not meet the nutrient requirements of cotton), there is no need to apply other fertilizers. Or only apply 20 kilograms per mu as base fertilizer, and then apply fertilizer according to the growth trend. (4) In the area of ​​"Middle Nitrogen, Low Phosphorus, High Potassium" cotton formula fertilizer (10-8-20), apply 50 kg per mu as a base fertilizer, and use urea foliar fertilizer in the middle and late stages to sustain 300 kg per unit yield, which is more cost-effective. In order to prevent production cuts, it can continue to be used in continuous cropping fields. (5) Fertile land is not suitable for growing cotton. If you can't avoid it, apply 50-75 kg of superphosphate as a base fertilizer per mu, and use small plant type early maturing varieties to avoid low-yielding and poor-quality cotton in the fertile land.

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