The role of three elements of nitrogen, phosphorus and potassium in cotton growth

Nitrogen has the most obvious effect on cotton, and the time is the longest. From the seedling to the flowering and belling period, an appropriate amount of nitrogen is required. Appropriate nitrogen supply, dark green cotton leaves, robust plants, many buds and bells, high yield and good quality.

Phosphorus can promote root development in the early stage of growth, make strong seedlings appear early, and play an important role in early flowering and early flowering; in the later stage of growth, it can promote cotton maturity and increase boll weight.

Potassium can play a role in strengthening branches and stalks and increasing resistance to adverse factors.

Principles of cotton fertilization

For every 50 kg of lint produced, cotton absorbs approximately 13.35 kg of nitrogen, 4.65 kg of phosphorus, and 13.35 kg of potassium from the soil. The ratio of nitrogen, phosphorus and potassium is 1: 0.3: 1. The principle of cotton fertilization should be based on basic fertilizers, supplemented by top dressing; organic fertilizers, chemical fertilizers.

Cotton high-yield fertilization technology

(1) Applying base fertilizer

The base fertilizer is compound fertilizer, organic fertilizer and trace element fertilizer. The compound fertilizer is best to choose a balanced or high nitrogen and potassium nutrient content, such as 18-18-18, 20-5-20 and other nutrient distribution ratios; organic fertilizers use high organic matter content, complete fermentation and contain a lot of beneficial bacteria.

(2) Topdressing fertilizer in stages

Based on the application of sufficient base fertilizer, the top dressing of cotton should be based on the principle of fertilizer demand. The principles of top dressing on cotton are: lightly applying seedling fertilizer, stably applying bud fertilizer, paying attention to flower bell fertilizer, and supplementing topping fertilizer.

1. Lightly apply seedling fertilizer

The seedling stage is generally dominated by nitrogen fertilizer, and it can also be applied in combination with phosphate fertilizer and rotten cake fertilizer. For example: 30-5-5 high nitrogen fertilizer, 10-15 kg / mu. The top dressing method uses deep trenching and covering the soil, and irrigates once in a small amount of water where conditions permit.

2. Steady Shi Lei fertilizer

Generally, a certain amount of medium phosphorus and high potassium fertilizer can be applied in the early stage of cotton buds. For example: a large amount of elemental water-soluble fertilizer 9-15-30 + TE (trace element) is applied, 4-6 kg per mu is applied, 500-1500 times of water is applied, and the application is performed once every 10-15 days.

3. Reapply flower bell fertilizer

Topdressing in this period is better at the initial flowering period. Generally, topdressing of high nitrogen and potassium fertilizers is appropriate. For example: 20-5-20 high nitrogen and high potassium, 20-25 kg / mu, the effect of potassium dihydrogen phosphate is better.

4. Apply topping fertilizer

For cotton fields with nitrogen deficiency, phosphorus deficiency, potassium deficiency, or long, greedy, and late-ripening cotton fields, a balanced water-soluble fertilizer 20-20-20 + TE (trace elements), 4-6 kg / mu, can be sprayed; especially against insect cotton fields It is advisable to spray more sprays as early as possible. For cotton fields where lei bells fall off more seriously, 0.2% borax solution 50-70kg can be sprayed per mu to achieve the purpose of high cotton yield.