Cotton

1. Nutritional characteristics

Cotton growth stage is divided into seedling stage, bud stage, flower and boll stage and batting stage. Lint yield is composed of three factors: total boll number per mu, weight of single boll and coat fraction. From the beginning of cotton bud to the end of effective flowering, for a single flower, the white flower primordium grows to the maturity of cotton boll batting. The cotton plant not only has long roots and leaves, but also has buds, flowers and bells. Both are interdependent and influence each other. The stable vegetative growth of cotton is the basis of reproductive growth, and there is no good vegetative growth. It's impossible to have good reproductive growth; Not a good shelf for fertility. There will be no more buds, no more flowers, no more bells.

2, need fertilizer characteristics

During the whole growth period of cotton, the amount and proportion of nitrogen, phosphorus and potassium required vary according to different factors such as soil, climate, varieties and planting methods. Cotton per mu yield of 100 kg (central China cotton field), nitrogen (N) 12 ~ 18 kg, phosphorus (P2O5) 4 ~ 7 kg, potassium (K2O) 15 ~ 20 kg; Cotton yield of 120 ~ 150 kg per mu (Xinjiang cotton field), nitrogen (N) 18 ~ 22 kg, phosphorus (P2O5) 8 ~ 10 kg, potassium (K2O) 6 ~ 8 kg.

The general trend of fertilizer demand in the whole growth period of cotton showed a dynamic change law of "less - more - less". The absorption amount increased significantly after the emergence of buds, reached the peak absorption at the flowering and bolling stage, and declined at the flocculation stage. The root absorption capacity weakened, resulting in a rapid decline in the absorption amount. The absorption characteristics of nitrogen, phosphorus and potassium in each growth stage of cotton are also different. The absorption peak of nitrogen fertilizer is in the front (from the beginning to the full flowering stage), and the absorption peak of phosphorus and potassium fertilizer is in the back (from the full flowering stage to the flopping stage), which is conducive to the application of phosphorus and potassium nutrition to the polyboll and promote the early ripening.

Zinc is the activator of many enzymes, and participates in the biosynthesis of auxin, which increases boll weight. Boron can promote the entry of other nutrients into cotton plant, promote the growth and development of root system and increase the rate of bolling. Manganese plays an important role in improving photosynthetic efficiency of leaves, enhancing seed vitality and increasing plant disease resistance. (Taken from the network, if there is infringement, please contact to delete.)

3. Fertilization technology

Base fertilizer: It is recommended to apply strong high-nitrogen and high-potassium special formula fertilizer (20-6-14) in central China cotton region, applying 40 ~ 50 kg per mu; It is recommended to apply strong high-nitrogen special formula fertilizer (22-10-8) in Xinjiang cotton area, applying 40 ~ 50 kg per mu.

Topdressing: For areas with high yield requirements, it is recommended to apply 5 ~ 10 kg of urea and potassium chloride in the cotton region of central China at the initial flowering stage, or apply 15 ~ 20 kg of high-nitrogen and high-potassium special formula fertilizer, and apply 5 ~ 10 kg of urea in the peak flowering stage. In Xinjiang cotton fields, it is recommended to apply 5 ~ 10 kg urea in the initial flowering period or 15 ~ 20 kg special high-nitrogen fertilizer in the special formula, and 10 ~ 15 kg urea in the full flowering period.

The spreading should be combined with the ploughing of the cultivated land into the soil or the furrow covering. The furrow application should pay attention to the separation of fertilizer and seeds, and keep at least 8 ~ 10 cm distance to prevent the burning of seeds and seedlings.