Key technical points for preventing five hazards and protecting three types of seedlings in cotton seedling beds

Common problems in cotton nutrient bowl seedling beds are mainly manifested as drought, waterlogging, disease, fertilizer, pesticide and frozen seedlings, burned seedlings, and spindly seedlings.

1. Prevent the "five hazards"

1. The water content in the bowls should be moderate. The nutrient bowl seedling bed should be selected in a place convenient for both drainage and irrigation. The water content in the bowls is best when the soil can be pinched into a ball by hand and falls apart upon hitting the ground;

2. After sowing cotton and covering with soil. Water thoroughly in one application, and water until it slowly infiltrates downward;

3. After covering with film, ensure sufficient soil moisture. Do not uncover the film at will, and do not uncover the film until the seedlings emerge completely;

4. Around the seedling bed, drain surface water and filter waterlogged water, so that the ditches are dry after rain;

5. Control diseases by paying attention to three key points. First, the nutrient bowl soil of the seedling bed and the fine soil covering the bowls after sowing must both be disinfected with chemicals to prevent pathogens in the soil from damaging cotton seedlings. Second, except for finely processed cottonseed that has already been disinfected, when using fuzzy seed and delinted seed for sowing, both must be treated with seed-dressing chemicals for sterilization. For disinfection of both soil and cottonseed, chemicals such as carbendazim and thiophanate can be used. Third, after the cotton seedlings emerge completely, spray chemicals such as Bordeaux mixture to prevent pathogen infection, but the dosage should not be too large, and the chemicals must not be sprayed repeatedly, so as to prevent chemical damage.

2. Prevent the "three types of seedlings"

1. Prevent cold damage: after the cotton seedlings emerge completely, when the temperature steadily passes 12°C, first uncover both ends of the seedling bed for ventilation, moisture reduction, and hardening of the seedlings, then gradually uncover it, to prevent spindly seedlings from growing excessively. When the temperature steadily passes 16°C, the film can be uncovered in the morning and covered at night, so that the bowls are not transplanted and the film does not leave the bed.

2. Prevent burned seedlings: when the atmospheric temperature reaches above 20°C, open the film day and night, and water to adjust soil moisture. At the same time, advocate raising seedlings in large bowls, placing bowls to restrain seedling growth, eliminating weak seedlings, controlling excessive growth and promoting healthy growth, and striving for earlyness while maintaining stability.

3. Prevent spindly seedlings: apply fertilizer according to the condition of the seedlings to cultivate strong seedlings. After the cotton seedlings emerge completely, those growing well only need one application of send-off fertilizer. Those with insufficient base fertilizer need two applications of fertilizer. The first should mainly be clear water and manure, and the second can apply 0.5% to 1.0% urea solution to promote the small ones to catch up with the large ones, so that strong seedlings leave the bed. But each time the fertilizer concentration should not be too high, and it is best to be dilute, quick-acting, and fast.