Technology of rational fertilization for Cotton

Popularizing the scientific fertilization technology of cotton is an important measure to improve the yield per unit area and product quality of cotton field.

Requirements of ammonia, phosphorus and potassium for Cotton and Fertilizer Application techniques

The results of field fertilizer experiment showed that for every 100 kg seed cotton, pure nitrogen, phosphorus pentoxide, potassium oxide and nitrogen: phosphorus pentoxide: potassium oxide were 5.0 kg, 1.8 kg, 4.0 kg and 0.360.8, respectively.

Rational application of base fertilizer. Base fertilizer should be based on organic fertilizer, combined with a certain proportion of chemical fertilizer. Generally, 2000 kg of pig and cow manure or 5000 kg of soil fertilizer are used per mu. Because phosphorus is difficult to move in the soil, and cotton is particularly sensitive to phosphorus in the early stage of growth and development, phosphate fertilizer should all be used as base fertilizer, generally using 50 kg superphosphate per mu. It is best to mix calcium superphosphate with organic fertilizer and apply it deeply in order to reduce the contact surface with soil. Calcium magnesium phosphate fertilizer should be composted with organic fertilizer or soil mixed fertilizer for 7 days and then applied.

Apply bud fertilizer steadily. The principle of bud fertilizer application is to require cotton plants to be stable but not crazy, which can not only build a high-yield shelf, but also show buds early, blossom early and sit peaches early, so as to lay a good foundation for high yield. Seedling fertilizer should be mainly organic fertilizer and phosphorus, potassium fertilizer, generally per mu with pig and cow manure 1500 kg or cake fertilizer 100kg.

Re-apply flower and boll fertilizer. Flower and boll fertilizer should account for about 50% of the total topdressing. Generally, 25% compound fertilizer 25,30kg per mu is mixed well with sifted soil miscellaneous fertilizer or dry fine soil 2000 kg, and the soil is applied in the trench when the first two big bolls are seated from the early flowering stage to the lower part, so as to improve the fertilizer efficiency.

Physiological Boron requirement characteristics and Boron Fertilizer Application techniques of Cotton

The content of available boron in cultivated soil of our province. The results of the second soil survey show that the content of available boron in cultivated soil in our province is seriously insufficient, with an average of only 0.26 mg per kilogram of soil. If 0.5 mg of available boron per kilogram of soil proposed by Nanjing Institute of soil Research, Chinese Academy of Sciences is taken as the boron deficiency critical value, 94.3% of the soil available boron in the province is in short supply.

Cotton is a dicotyledonous plant, which requires more boron than monocotyledonous plants, and has a high boron content in the plant. The normal boron content per kilogram plant is 20mg / kg. When it is lower than 20mg, it is boron deficiency. Cotton began to absorb boron nutrition from the seedling stage, and the boron absorbed by cotton accounted for 45.4% of the total amount of boron absorbed during the whole growth period to the boll setting stage, and 65.95% of the boron absorbed by cotton was distributed in the reproductive organs.

Boron fertilizer can promote the growth and development of the root system, improve the physiological function of the root system, promote the early development of strong seedlings, increase the leaf emergence rate of true leaves, promote the transport of carbohydrates in cotton plants, and coordinate the balance of growth and development of cotton plants. it is beneficial to the stable growth, early maturity and no premature senescence of cotton plants, effectively prevent the phenomenon of "bud but not flower" of cotton, reduce the shedding rate of buds and bolls, and increase the number of peach per plant, boll weight and lint percentage per plant. It can improve cotton quality, increase fiber length and lint percentage.

When the cotton is boron deficient, the root growth is blocked, the lower leaves become larger, the top new leaves become smaller, the petiole has infiltrating bands, the growth point of the main stem is damaged, the axillary buds are clustered, the buds and bolls fall off, the phenomenon of buds but not flowers is serious, the Corolla is shortened, it is not easy to stretch, and it is difficult to become a peach, which seriously affects the cotton yield.

The application techniques of boron fertilizer in cotton are as follows:

Basic application of boron fertilizer. Mix 0.51kg borax with 2000 kg sifted soil fertilizer or dry fine soil per mu and sprinkle it on the soil, then plough and prepare the soil, sow or transplant nutrition bowls.

Make a kind of fertilizer. Mix 0.51kg borax with 2000 kg sifted soil fertilizer or dry fine soil per mu and apply it in sowing or transplanting ditches and holes. Should pay special attention to evenly, avoid contact with seeds, do not mix seeds, do not cover seeds, and do not apply directly below the seeds, so as not to hinder seed germination and seedling growth.

Foliar spray. Foliar spraying boron fertilizer not only avoids leaching loss, but also avoids chemical fixation caused by direct contact between boron and soil, which is the most economical and effective application method. At the same time, spraying in different stages can better meet the needs of boron in different growth stages of cotton.

During the spraying period. The best period of spraying boron fertilizer on cotton leaves is bud stage, early flowering stage and flowering and boll stage.

Apply the amount. Generally, 200 grams of borax per mu has the best effect of foliar spraying with 100 kilograms of water.