Cotton

Seed material preparation

• Gin - damaged seeds may exceed 10 percent and such seed will produce abnormal seedlings.
• Seeds with a germinative ability or less than 80 percent should not be used.
• The content of free fatty acids in the seeds may vary from 0.5 to 8 percent, the higher the fatty acid content of the seed is, the lower will be the germination rate. Hence, seeds that have a fatty-acid content in excess of 0.75 percent should not be used for sowing.
• The rapidity of germination is also an important characteristic of the seed: it is considered satisfactory if two-thirds of the seeds germinate in one-third of the time that is considered necessary for the completion of germination.
• A number of cotton diseases are seed-borne. Before selection and sowing of seed ensure that the seed is disease-free.

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Seed Rate and Spacing

• The optimum number of plants per unit area, and the distance between and within the rows depend on the inherent vegetative habit of a variety and conditions of soil fertility, soil moisture and cultural practices. For instance, the optimum number of plants per unit area in the case of a highly branched monopodial variety is much less than that in the case of a non - branching, sympodial type.
• Similarly, under conditions of good plant growth, such as, greater fertility of the soil, availability of irrigation facilities and early sowing, the number of plants per unit area (particularly of varieties having tall, vigorously branching plants) has of necessity, to be smaller than on relatively poor soil, or under late sowing and un-irrigated conditions in which the plants do not make a vigorous growth and the per plant yield is relatively low.
• In case of non - branching varieties, on the other hand, close spacing gives the best results even on rich soils.
• The optimum number of plants under different conditions varies widely and has to be secured by judicious variations of spacing and seed rate.
• In working out proper seed rate for a variety for a given set of environmental or cultural conditions, due allowance has to be made for the spacing adopted, the seed size, the germination capacity of the seed and the mortality of the plants caused by diseases, insect pests, vagaries of the season and physiological disorders.
• In the case of American cottons the relative fuzziness of the seed has also to be taken into account. However, it may be stated, that in actual practice, most of the cotton growers do not adjust the seed rate to the optimum number of plants suitable heavy seed rate to provide against failure of germination and mortality or young seedlings due to pest or disease or other natural calamities.
• A large number of seeds is also believed to help the emergence of seedlings through surface crust.
• Only the intelligent farmers who make due allowance for these factors and adopt a wider spacing in the case of more fertile soils, and closer spacing when the crop is sown rather late in the season or is grown on rather poor soil.
• Late sown crops and those grown on less fertile soils have to make up the deficiency of yield by a greater number of plants per unit area.
• In intercropping, the seed rate for cotton is not materially reduced if the rows of the subsidiary crop are placed at relatively long intervals.
• When the soil farm crust at surface, cotton seeds are sown with 3-4 cowpea or sunhemp seeds, so that cotton seedling emerges easily out of soil.
• In Karnataka, the hybrid cotton is sown at a distance of 120 cm or 90 cm between rows and 60cm between plants. In hirsutum varieties, these are reduced to 60 cm /75 cm between rows and 30 cm between plants. In a herbaceum / arboreum varieties, they are 45 cm and 30 cm respectively.

Seed rate (kg/ha):

Note : Follow recommended seed rate and treat the seeds with commercial Sulphuric acid before sowing to separate the seeds from the lint to get maximum germination percentage.

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Seed soaking

• Soaking of desi cotton seed for two or three hours and that of fuzzy American varieties for four to six hours in water before treatment with mud and cow - dung, hastens germination and there by gives a better start to young seedlings and also ensure a more uniform stand of plants.
• The soaking of seed before sowing is a common practice in many parts of the country but where it is not so, it should be advocated for both irrigated and rainfed cottons. Insect-damaged and immature seed floating on the surface of water is removed and discarded.
• The benefits are more pronounced in the case of American varieties and the re-sowing of gaps in a rainfed crops.
• In rainfed regions, soaking the seeds for 8.10 hours and later drying them in shade for 1-2 hours is recommended before sowing. This process is called seed hardening. It is useful for rainfed crop – as it imparts better capacity to withstand the moisture stress during initial days of establishment.

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