When is the flowering and boll period of cotton? How to control the management of water and fertilizer? How to apply fertilizer?

After the cotton topping, it entered the flower and boll stage, which is not only the key period for the formation of cotton yield, but also the peak of water and fertilizer demand, during which cotton field management is very important. When is the florescence and boll period of cotton? How to control the management of water and fertilizer?

When is the flowering and boll period of cotton?

The period from the beginning of cotton flowering to the mature cracking and opening of cotton bolls is called the flowering and boll stage, usually from early July to late August. During this period, cotton developed from vegetative growth and reproductive growth, and turned to reproductive growth, not only long roots, long stems, long branches and long leaves, but also budding, flowering and bolls. It is the most vigorous period of growth and development of cotton in its life, the peak of fertilizer and water demand, and the key period for the formation of yield and quality.

60% of nitrogen, 65% of phosphorus and 62% of potassium are absorbed from flowering-opening, so timely and appropriate application of fertilizer can promote cotton peach, prevent premature senescence, produce more three peaches, reduce shedding, increase boll weight and increase lint percentage.

Matters needing attention in water, fertilizer and chemical control in July

(1) Fertilizer functions of nitrogen, phosphorus, potassium and trace elements:

Generally speaking, nitrogen fertilizer determines plant growth, phosphorus fertilizer determines plant growth health, potassium fertilizer determines resistance quality, zinc fertilizer in trace elements participates in auxin synthesis, boron fertilizer promotes the growth and development of reproductive organs, etc.

(2) the utilization rate of nitrogen, phosphorus and potassium:

The utilization rates of nitrogen, phosphate and potash are 30-40%, 15-25% and 30-50%, respectively.

(3) the principle of cotton topping:

The principle of cotton topping is to hit the weak first and then the strong, the dense first and then the thin, the strong first and then the strong. Many farmers do not understand why they should fight weak first and then be strong. Cotton weak seedlings are weak because the growth process is slow, and the current time requires vegetative growth to transform into reproductive growth, but the transformation of weak seedlings is slow. however, if the weak seedlings are launched later, the buds will be washed away to maintain the nutrients needed to maintain the vegetative growth, there is basically no peach in the middle after the peach top in the later stage, and the peach ripening period is relatively late. If the frost period comes earlier are basically peaches, this situation must block its vegetative growth as soon as possible, leave less fruit branches, and ensure the basic yield.

(4) principles of fertilization for cotton

The combination of organic and inorganic, the combination of a large number of elements and trace elements, the combination of fertilizer production and soil testing formula; fertilization methods: full base fertilizer, light seedling fertilizer, stable bud fertilizer, heavy boll fertilizer, top fertilizer.

Re-apply flower and boll fertilizer:

Cotton plants should not grow excessively in fertilization, and cotton fields with high fertility and vigorous plant growth can be fertilized late. For example, 3-5 days after topping, 2-3 kg of urea, 3-5 kg of phosphate fertilizer and 1-2 kg of potash fertilizer can be dripped with urea, 3-5 kg of phosphate fertilizer and 1-2 kg of potash fertilizer. Heavy water fertilizer must be postponed to 1-2 big peaches in the lower part of the plant at full flowering. In cotton fields with low fertility and weak growth, flower and boll fertilizer should be re-applied early in the early flowering stage. Generally speaking, drip irrigation is carried out in combination with drip irrigation in early July, and the principle of "one water and one fertilizer, water and fertilizer, fertilizer determined by water and water transfer by fertilizer" is mastered per mu. These fertilizers are applied in stages, and after topdressing, timely watering and chemical regulation should be carried out according to the weather and the growth of cotton. It can be properly combined with foliar fertilization. Generally, 1%-1.5% potassium dihydrogen phosphate mixture is foliar sprayed 1-2 times, each time at an interval of 7 days.

The time of re-application of flower and boll fertilizer after cotton topping should be carried out in 5-7 days of secondary chemical control. if cotton does not have secondary chemical control to lock the cotton top, large water and fertilizer will enter, it is easy to wash the top away, and when small villi appear at the top, the top will consume a lot of nutrients. In this case, the peach can not be seated.

Make up the top fertilizer:

Capping fertilizer can prevent premature senescence, shedding, more bolls and increase boll weight. Whether topdressing should be applied or not depends on soil fertility and cotton plant growth. For late-maturing cotton fields with sufficient fertility and strong cotton plants, saline-alkali land and clayey land, little or no top fertilizer should be applied to prevent greedy green late ripening, and early and more application should be applied to sandy land and cotton fields where cotton plants have a tendency of premature senescence.

(5) fertilization methods for cotton:

From flowering to boll-opening, nitrogen accounts for 60%, phosphorus 65%, potassium 62%. At this stage, these nutrients should be applied step by step according to "less-more-less". In view of the differences in water and fertilizer between the prosperous and long cotton fields and the late topping cotton fields in southern Xinjiang and northern Xinjiang, for example, during the period of topping in southern Xinjiang from July 10 to 15, the water and fertilizer high festival is as follows:

For example, general plots (according to one water for 8-10 days): dripping water in cotton field on July 10.

On July 15, there are 2-4 kg of urea, 4-5 kg of phosphate fertilizer, 2-3 kg of potash fertilizer, and 5-8 g of ketamine on July 13.

On July 24, there were 3-6 kg of urea, 5-6 kg of phosphate fertilizer and 3 kg of potash fertilizer. On July 20, the thalidomide sealed the top, and the dosage per mu was 10-15 grams according to the situation of cotton.

On August 3, there were 6-8 kg of urea, 4-5 kg of phosphate fertilizer and 3-4 kg of potash fertilizer.

On August 12, there were 6-8 kg of urea, 3-5 kg of phosphate fertilizer and 4-5 kg of potash fertilizer.

On August 21, there were 5-6 kg of urea, 2-3 kg of phosphate fertilizer and 4-5 kg of potash fertilizer.

On September 1, water drop 1-2 kg, phosphate fertilizer 1 kg, potash fertilizer 1 kg (no premature senescence land without fertilizer this time) if the amount of water is increased appropriately every 10 days, and so on.

The fertilization time of high fertility plots is postponed and the amount is appropriately reduced, and the amount of fertilizer is properly increased in low fertility plots.

(6) the application of micro-fertilizer:

Cotton is sensitive to boron. The application of boron fertilizer can prevent cotton "bud but not flower" disease, increase boll rate and promote peach. Where the soil available boron content is less than 0.5 mg / kg, boron fertilizer should be increased and foliar spraying, generally using 20.5% granular boron solution 100-200 g per mu. Use once in full bud stage, first flowering stage and full flowering stage.

(7) points for attention:

1. Do not mix phosphate fertilizer and zinc fertilizer (except zinc chelate) to avoid antagonism and reduce fertilizer efficiency.

2. Fertilization and regulation (the secondary chemical control extends 3-5 cm at the top of the fruit branch with 5-8 grams of thalidomide, and 10-15 grams after 7-10 days. This year, the weather is limited due to the early disaster weather, and the cotton is more aggressive after the temperature rises in the later stage. During the secondary chemical control, the amount of fertilizer application is not easy to be too large, and the secondary chemical control must be controlled.), the combination of water and fertilizer and chemical control to avoid crazy growth.

3. Potassium chloride should not be applied in soil salinized cotton field so as not to aggravate soil salinization.

Factors that are easy to cause falling flowers and bells in July

The main results are as follows: 1. In the early disaster weather, the cotton is not long, the root system is generally shallow in the early water intake, and the ability of the root system to absorb fertilizer is limited in the fertilizer period, resulting in falling flowers and buds due to insufficient nutrient supply.

2. The effect of canopy closure in the field on the functional leaves of cotton caused serious bud and boll shedding. Cotton is not long in the early stage of this year, and many farmers used some hormone foliar fertilizers to promote seedlings, which made the leaves very strong, resulting in functional leaves not being able to provide nutrients to cotton bolls by photosynthesis.

3, the threat of diseases and insect pests, due to the disaster weather in May, cotton is relatively tender. The occurrence of diseases and insect pests is more serious, such as aphids and Fusarium wilt, causing a large number of buds to fall off.

4. The density greatly affects the development of buds and bolls. In high-density cotton fields, the canopy closes earlier, resulting in many small buds and shedding of buds and bolls.

5. Water and fertilizer is unreasonable. Due to the weak growth of cotton seedlings in the early stage, many farmers promote the seedlings earlier and apply more urea, which makes the vegetative growth too prosperous, resulting in the cessation or slow progress of reproductive growth, and the phenomenon of small buds or slow buds.

To prevent falling flowers and buds, we must start with water and fertilizer and amine control after topping.

1). The timing of fertilization should be grasped, such as: do not wash the ground with water and fertilizer before the safflower goes to the top, which will make the middle, upper and peripheral buds not easy to hold, and excessive water and fertilizer will easily transform the cotton field from reproductive growth to vegetative growth again.

2), the secondary chemical control must be in place, and the secondary chemical control, especially the second locking, must be locked at the first time, such as being washed away by leaf buds and consuming nutrients, the peach is unstable, so that the peach can not be seated.

3), large water and fertilizer must be locked at the top, and 3-4 fruit branches in the middle and lower parts can be carried out above the peach seat.