Topping or pruning of cotton

• The removal of the tip of the main stem alone or together with the tips of the other branches a few weeks before the balls begin to open is a practice known as topping or pruning.
• The main purpose of topping is to ensure a redistribution of the nutritive substances in the plants.

There are two types of topping:

• Ordinary Topping: In the ordinary topping, the tips of the main stem and vegetative branches are removed.
• Drastic Topping: In drastic topping, the tips of the main stem, vegetative branches and all fruiting branches are removed.

Defoliation

• Defoliation is the process of removal of leaves of cotton plants by using certain defoliant chemical.
• Defoliants such as magnesium chlorate (MgCl2), hexahydrate, calcium cyanamide are used to defoliate cotton to enhance boll opening and control re-growth prior to harvest.
• At least 60% balls should be opened when defoliants are applied because ball fiber development is checked when the leaves are removed.
• Defoliation improves efficiency of hand picking and also prepares cotton for mechanical harvest also.

Desiccation

• Desiccation is the process of rapid death, dry and break off of leaves for easy and early harvesting of the crop.
• The desiccants are more drastic than defoliants so they are generally applied 10-12 days after application of defoliants.
• It can be said that that typical defoliants may act in the same way as desiccants if applied in excessive rates.