Questions and answers on Field Management techniques of Cotton at Flower and Boll stage

1. What is the flowering and boll period?

From flowering to opening bolls, generally from early July to early September, there is a saying that "flowers see flowers 48". In fact, it takes 50-70 days in the Yellow River basin in China. When 10% of the cotton plants in the cotton field bloom, it is called the initial flowering stage; when there is 50% flowering, it is called the flowering stage; when the first fruit node of the fourth fruit branch of 50% of the cotton plant blossoms, it is called the full flowering stage.

2. What are the management principles of the flower and boll period?

The early flowering stage is mainly from vegetative growth to reproductive growth, and the management should be mainly controlled to prevent excessive growth and achieve stable growth. The full flowering stage changes from vegetative growth to reproductive growth, which is not only the period when cotton needs the most water and fertilizer in its life, but also the period when contradictions are most concentrated in growth. It is necessary to meet the needs of water and fertilizer for growth and development, but also to control the vegetative growth of cotton plants and to transfer nutrients to reproductive growth. Management should adopt the way of promoting upward control or the combination of promotion and control, mainly applying flower and boll fertilizer. The peak period of flower and boll is a period from vegetative growth to reproductive growth. In order to meet the water and fertilizer needs of cotton growth, it is necessary to promote peach bearing in the middle and upper parts, and strictly prevent premature senescence in the later stage.

3. What is the main cause of bud and boll shedding?

When it blossoms, when it rains, the pollen absorbs water and loses its ability to pollinate or inseminate badly. The cotton field has high humidity after rain, high temperature, poor ventilation, poor coordination between water, fertilizer and temperature, which intensifies the physiological contradiction. Poor external environmental conditions lead to nutritional disorders and out of control of physiological functions of cotton plants, such as insufficient or excessive soil moisture, excessive or insufficient nitrogen application, high or low temperature, insufficient light, diseases and insect pests, mechanical damage and so on.

4. How to judge the appearance of cotton plant at flowering and boll stage?

The appearance of ① at the flowering and boll stage:

The color of the leaves is light green, the plants are strong, the flowers and bolls fall off less at the waist, the top leaves are black and lack of water, and the top leaves are shiny and less fertilizer, cotton field management first look at the phase.

② healthy type:

The first flower is robust and has potential, the flower is fat and the shelf is sufficient; the blossom is exuberant, the growth is strong and the peach is stable; the waist is not empty with peach seal, and the three peaches are full and fall off light.

③ progeria type:

The cotton plant is short with few fruit branches, the main stem is weak and grows slowly, the stem is red to the top leaf is yellow, and the autumn peach is thin and shedding heavy.

④ overgrown:

The stem green branches are sparse and the internodes are long, the leaves are tender and green with yellow, the leaf tips are drooping, the leaves are wide, and the sealing lines are high and empty too early.

5. What are the basic measures for cotton field management at flowering and boll stage?

Pruning: the simplified pruning cultivation technique (limited to "Guoxin" brand GK-12 and 95-1) can be adopted in cotton fields where the number of trees per mu in the Yellow River basin does not exceed 3000 in dry years and 2500 in waterlogging years, otherwise pruning measures should be taken. That is, in the bud stage, the lower vegetative branches should be removed first, and with the growth process of cotton, the superfluous buds on the main stem and fruit branches should be removed in time, so as to save nutrients, reduce consumption, control excessive growth and reduce shade in cotton fields. Beat all the middle and upper sides after August 10, and remove the superfluous buds and invalid buds on the fruit branches.

Topping: topping too early, the upper fruit branch is too long, it is easy to cause shade in the lower part. If the top is too late, the upper fruit branch can not stretch out, forming a small late autumn peach. According to different varieties, different soil fertility, different density to control the topping time flexibly, generally in the middle and late July, no later than the end of July at the latest. The general principles are: early beating in thin land, late beating in dry days, early beating in dry days, late beating in waterlogged days, early beating in dense planting, late beating in sparse planting, early beating in lower peaches, late beating in cotton fields, early beating in cotton fields and late beating in cotton fields. Strengthen the prediction of insect pests and control diseases and insect pests in a timely manner. The main pests in the boll stage of insect-resistant cotton are bug bugs, and red spiders are rampant in dry weather. It is necessary to strengthen pest prediction and control as soon as possible, so as to eliminate pests in egg and larval stages. Water properly. Drought in the early flowering stage, watering thin water; drought watering in full bloom; be sure to pay attention to full watering in summer drought and timely drainage in case of flood. Pay attention to flower and boll fertilizer. "Guoxin" brand GK-12 budding, flowering and boll setting are early and concentrated, so it is necessary to topdressing and watering as soon as possible to promote the vigorous growth of the flower and boll stage. Strong stamina to prevent premature senility. In the cotton field with general soil fertility, topdressing begins at the early flowering stage; in the cotton field with sufficient soil fertility, the lower part of the cotton field is topdressing at 1-2 bolls. The general soil fertility is 20-30 jin of nitrogen fertilizer per mu. Insect-resistant cotton has a great demand for potash fertilizer. If the stamina is insufficient, the leaf surface of 1.5% urea solution mixed with potassium dihydrogen phosphate 2-4 per mu is sprayed many times (5 days apart). Reasonable chemical control. In the cotton field with exuberant growth in waterlogging years, 3-4 grams of Anyuan powder can be used at a time, 60-80 jin of water, foliar spray and reduction in dry years.

6. Which cotton fields should take remedial measures?

Cotton fields with high density, such as density more than 3000 trees (Yellow River Basin), can not be cultivated without pruning, but should be pruned in time. For cotton fields with serious shedding in the middle and lower parts due to improper mid-term management or exuberant growth due to excessive water and fertilizer, it is necessary to properly control water and fertilizer, postpone the time of topdressing and reduce the amount of topdressing.