After the top of cotton should be top dressing

Generally, cotton is topping at the flowering stage. It is during the best flowering and ringing period, and afterwards, effective flowering and ringing should be maintained for 30 to 40 days. This section is a crucial period for determining cotton production.

The cotton flowering and bolling stage requires the peak period of moisture and nutrients. The absorbed nutrients are equivalent to about 2/3 of the amount of absorbed nutrients in a lifetime, and the ratio of nitrogen, phosphorus and potassium absorbed is roughly 3:1:3 (according to N:P205: K20 calculation) also accounts for about 2/3 of the total absorption of a lifetime. After the cotton is topping, it is the time when each part of the organs competes for the most intense nutrients. The development of young bells requires nutrients, the buds increase, the flowering needs nutrients, the elongation of the upper fruit branches and the emergence of new leaves and buds require nutrients. Insufficient supply of nutrients is not the reduction of the middle and lower parts of the bell, which is the absence of bells in the upper part, or the premature decline of the cotton plants after the bell, the loss of leaves and the reduction of the boll weight. Can not reach the purpose of high yield.

After the cotton plant is topping, it is almost always flowering and ringing. Sometimes a flower blooms from two to several flowers a day. Therefore, the demand for nutrients after the cotton is topping is continuous and one day is essential, because the top growth advantage after topping has been If it does not exist, the young bells after flowering become the strongest contenders for nutrients. If they cannot meet their needs, they are discarded and shed by the cotton plants. Therefore, young bells that have been 1-4 days after flowering become the most easily detached reproductive organs. Insufficient nutrients will also cause the young buds to fall off. This will require the use of fertilization and fertilizer supplements. How to make up fat? It is necessary to insist on the simultaneous and timely supplementation of the ratio of nitrogen, phosphorus and potassium required for cotton. Can not think that you have applied the base fertilizer and follow the fat you do not need to make up for the fertilizer. Most of the previous fertilization has been absorbed or utilized by cotton. Except for a few fertile soils or soils with a large amount of organic fertilizers, most soils cannot meet the demand for nutrients during the blooming period of cotton. However, soils that can meet the nutrient requirements of cotton by nitrogen, phosphorus, and potassium are scarce.

After the topping of the cotton, the root fertilizer and foliar spray fertilizer can be used to combine nitrogen and potassium. The phosphorus-deficient soil must also be supplemented with phosphorus. According to the high-yield requirements of cotton, the soil generally has 15 kg of urea. 15 kg potassium fertilizer is appropriate. 15 kg of urea with pure N6.9 kg, 15 kg of potassium sulfate

K207.5 kg, calculated according to the fertilizer utilization rate of 40%, can provide pure N2.8 kg of cotton, K203 kg, which is the nitrogen and potassium, enough to produce 60 kg of seed cotton, and can greatly reduce the late Verticillium wilt of cotton Occurrence and hazards. In fertile oyster fields, organic manure, and long-growing cotton fields, it is necessary to control the application of nitrogen fertilizers. Nitrogen fertilizers must be strictly prohibited in cotton crops grown in vain, and potassium fertilizer and phosphate fertilizer should be added to consume excess nitrogen. It can be seen that supplementing fertilizers after topping is not optional for cotton, but is an important measure that affects the level of output. (China Agriculture Technology Association Cotton Committee Senior Consultant Liu Chuntai)


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