Key Points of Cotton Fertilization Technology in the Huang-Huai-Hai Region

1. Main existing problems

In the Huang-Huai-Hai cotton region, nitrogen and phosphorus fertilizer application rates are generally too high, while organic fertilizer application is insufficient; basal fertilizer rates are too high, while topdressing rates are insufficient; deficiencies in the trace elements boron and zinc are relatively common.

2. Fertilization principles

(1) Increase organic fertilizer application and advocate combining organic and inorganic fertilizers.

(2) According to soil fertility conditions, appropriately reduce nitrogen and phosphorus fertilizer rates, apply potassium fertilizer reasonably, and pay attention to the combined application of boron and zinc.

(3) Apply nitrogen fertilizer in split applications, appropriately increasing the proportion of nitrogen fertilizer applied in the middle growth stage.

(4) Fertilizer application should be combined with high-yield and high-quality cultivation techniques. 3. Fertilizer rates and proportions

Under the condition of a lint cotton yield of 70-90 kg per mu, the total fertilization amounts are 2000 kg of high-quality organic fertilizer per mu, nitrogen fertilizer (N) 11-13 kg, phosphorus fertilizer (P2O5) 5-7 kg, and potassium fertilizer (K2O) 5-7 kg. For cotton fields deficient in boron and zinc, pay attention to supplementing boron and zinc fertilizers. The application rate of boron and zinc fertilizers is 1-2 kg per mu; for foliar spraying, the concentration is 2 g/L, applied from the squaring stage to the flowering stage.

35%-40% of nitrogen fertilizer is used as basal fertilizer, 30%-35% is applied at the early flowering stage, and 25%-30% is applied at the full flowering stage; all phosphorus fertilizer is used as basal fertilizer; all potassium fertilizer is used as basal fertilizer or split equally between basal and topdressing (at the early flowering stage). Starting from the full flowering stage, for cotton fields with weaker growth, mix and spray 0.5%-1.0% urea and 0.3%-0.5% potassium dihydrogen phosphate solution at 50-75 kg per mu together with pesticide application, once every 7-10 days, for 2-3 consecutive sprays.