Do cotton plants still need topdressing after the flowers have opened all the way to the top?

In early August, we went to some concentrated cotton-producing areas to investigate and found that some cotton plants had already bloomed all the way to the top of the plant, and the color of the cotton main stem had also turned red up to the top. Farmers asked: Can cotton like this still be topdressed?

Faced with such a question, the specific situation must be analyzed specifically. Generally speaking, if cotton has bloomed to the top in early August and the cotton stalks have also turned red to the top, it indicates that the cotton plant itself is suffering from malnutrition. Either the cotton field's fertilizer supply is insufficient, causing the cotton to suffer from fertilizer deficiency, and vegetative growth and reproductive growth have been inhibited; or fertilizer has already been applied but the cotton plant has not yet absorbed it; or early vegetative growth was excessive and premature senescence appeared later; or nitrogen fertilizer was applied in a one-sided way, and the fertilizer was lost too quickly.

Normally growing cotton should generally be "tender in August," with strong late-season potential, and the peak period for concentrated boll setting is from late July to early August. This year's early low temperatures and continuous rain delayed cotton growth and development by 10-15 days compared with normal years, and the multiple heavy to torrential rains in July caused relatively large nutrient losses in cotton fields. If late-stage management is not strengthened for cotton that has bloomed to the top and whose stems have turned red to the top, it will have a great impact on achieving a bumper cotton harvest this year. Therefore, measures must be taken quickly to strengthen cotton field management, enhance the cotton's late-season potential, and strive to recover the losses caused by the floods.

There is still half a month left in the effective squaring period for cotton, and more than 30 days left in the effective flowering period. If management during this period is done well, the cotton can produce more squares, more flowers, more bolls, and larger bolls. At present, the focus should be on applying flower and boll fertilizer as soon as possible. For those in the flowering and boll-setting stage, the main approach should be supplementary topdressing of urea and potassium sulfate fertilizer; for those that have already entered the peak boll-setting stage, the main approach should be topdressing urea, and the amount applied should be determined by the cotton's growth conditions; at the same time, urea, potassium sulfate, and potassium dihydrogen phosphate solutions should also be sprayed on the leaves.