Applying boll fertilizer to cotton pays off, and this investment account must be calculated clearly

This year, due to early drought followed by flooding and the recent hot, high temperatures, cotton development progress has been very uneven. In particular, the number of bolls set on cotton varies greatly. In cotton fields planted earlier and managed better, the average number of early summer bolls per cotton plant has already reached 8 to 10, and for high-yield cultivation farmers, the early summer bolls on cotton can be as many as more than 20, while in general fields the early summer bolls on cotton are only 4 to 6.

From the perspective of cotton's growth process, field cotton has now generally entered the boll-setting stage. The period when cotton concentrates on setting bolls is precisely the period of greatest fertilizer demand. From the stages divided by cotton boll setting, bolls set before July 15 are called pre-summer bolls. Bolls set from July 16 to August 15 are summer bolls, among which bolls set at the end of July are called early summer bolls, and bolls set from the end of July to August 15 are late summer bolls. Bolls set from August 16 to September 15 are autumn bolls. The current weather is precisely favorable for setting a large number of summer bolls in a concentrated way, and we should seize the opportunity to apply boll fertilizer well and in sufficient quantity.

Regarding increasing the application of boll fertilizer, some farmers have concerns. Some believe that base fertilizer was already applied sufficiently earlier, or fertilizer was applied before the rain, so it need not be applied again; some farmers fear that applying boll fertilizer will cause cotton to become shaded and closed in; some believe that applying more fertilizer in the later stage of cotton has little effect and would avoid waste; and some believe that for applying boll fertilizer, just spreading a little urea is enough. For this reason, we must improve understanding through calculating and comparing accounts, and give full play to the great role of boll fertilizer in increasing cotton yield.

Several accounts should be calculated well. First, the effective season account. The effective squaring period of general cotton is around August 20, and the effective flowering period is around September 10. Applying boll fertilizer now still leaves a very long effective growth period, and applying it can be effective. Second, the boll fertilizer cost account. People are accustomed to using urea as cotton boll fertilizer. The current market price is 1.2 to 1.3 yuan per jin of urea, and 15 kg per mu costs nearly 40 yuan. Third, the investment return account. According to many years and many locations of practice, applying boll fertilizer compared with not applying boll fertilizer can increase seed cotton yield by 15 to 25 kg per mu. Calculating on the basis of an average increase of 20 kg of seed cotton and an estimated selling price of 5 yuan per jin of seed cotton, income can increase by 200 yuan per mu, and the ratio of input to income is 1:5, which is still very worthwhile.

Clarify the fertilizer requirement pattern of cotton. Knowing the transport pattern of cotton fertilizer is of great practical significance for guiding field cotton fertilization. According to research by agricultural scientific research departments, before cotton sets bolls in large numbers, nutrients are mainly transported to the cotton plant's growing point. After the cotton plant sets bolls in large numbers, nutrients are mainly transported laterally to the cotton bolls on the fruiting branches. Therefore, when applying boll fertilizer, there is no need to worry about excessive vegetative growth or shading and closing in.

Apply boll fertilizer sufficiently and well. First, according to this year's cotton growth condition, apply boll fertilizer well by category. For those with more bolls set, boll fertilizer can be finished before August 10, and for those with slower boll-setting progress, the time for topdressing boll fertilizer can be appropriately extended. Second, the amount of fertilizer applied is generally about 15 kg of urea per mu, and potassium-deficient cotton fields should also be supplemented with 10 kg of potassium fertilizer per mu. Third, the fertilization method is preferably hole application before rain. Never broadcast urea before rain, so as to prevent burning the cotton seedlings.