Jinnan District Agriculture and Forestry Bureau reminds cotton farmers to master the management techniques of cotton flowering and boll stage.

The flowering and boll period of cotton in Tianjin generally begins in early July and ends at the end of August, which lasts 55 days. According to the survey, most of the cotton fields in our district have entered the flowering and boll stage. The field management of flower and boll stage is very important, which is the most exuberant period of cotton growth and development, a period of complex contradictions between vegetative growth and reproductive growth, individuals and groups, cotton crops and environment, so it is a period to determine yield. The cotton field management in this period should pay attention to the following key work:

1. Increasing potassium fertilizer can prevent physiological red leaf stem blight and cotton premature senescence, improve cotton quality and increase cotton yield. From full bud to early flowering stage, 10 kg of nitrogen and potassium compound fertilizer was applied per mu, and the application rate of nitrogen and potassium compound fertilizer was increased step by step according to the cotton plant growing from mere growth to general growth. The application of nitrogen and potassium compound fertilizer per mu in thin cotton field can reach more than 20 kg and promote growth.

2. Chemical regulation technology Chemical regulation and control should master the principle of "light in front and heavy in back, a small number of times", strengthen chemical control after flowering, shape plant type, prevent overgrowth, and protect flowers and bolls. According to the variety, cotton plant growth, soil fertility and planting density, there was no application of metoprolol in June. Cotton plants entered the early flowering stage with 1 ~ 2 grams of propranolol and 15 kg of water. 15-20 days later, in late July, 3 ~ 5 grams of Juan was sprayed evenly with 25 kilograms of water. When the precipitation frequency is more and the precipitation is large, shorten the use interval and increase the usage.

3. The integrated pest control technology gives priority to chemical control of cotton pests, supplemented by biological control. Strengthen the control of piercing and sucking pests, and pay special attention to the control of bug bugs. 2.5% nail bugs were sprayed with 10% imidacloprid or 3% acetamiprid 2500 times per mu. The time to control bug bugs is before 9 o'clock in the morning and in the evening after 5 o'clock in the afternoon. In July, the third generation of cotton bollworm will occur, the resistance of insect-resistant cotton varieties will gradually weaken, and a few non-insect-resistant cotton varieties will not be resistant to cotton bollworm. Use phoxim 1000-1500 times or acephate 800-1000 times spray.

4. Scientific pruning technique for conventional cultivation of cotton fields, generally leaving 12-15 fruit branches per plant, the suitable topping time is around July 15, which can end on July 25 according to plant growth. This year, cotton plants grow fast and grow well, according to the principle of "unequal branches, time to unequal branches". Hit the tip of the group in batches according to the reserved fruit section. Generally, each fruit branch leaves about 3 fruit nodes to simplify the cultivation of cotton field, which is generally divided into two times, that is, leaf branch and main stem topping. When the first dominant leaf branch of 80% cotton plant in the field grew 3-4 secondary fruit branches, the leaf branch of the whole plant topped in time. The topping time of the main stem can be carried out from July 15 to 20. The production can be flexibly mastered according to the growth of the cotton field, and the superfluous buds can be used to hit the tip of the group as appropriate.

5. Drainage and waterlogging cotton flower and boll period is in rainy season, precipitation is relatively concentrated, stagnant water is easy to cause waterlogging, it is necessary to dredge drainage ditches, eliminate weeds and ensure smooth drainage.