What are the key technical measures for ensuring a full stand of cotton seedlings in spring?

Seed preparation. Choose superior seeds; high-quality seeds are the prerequisite for ensuring the emergence rate and for uniform, complete and strong seedlings. Therefore, choose seeds produced and sold by large manufacturers, with standardized packaging, good maturity and plumpness, and a high germination rate.

Chemical seed dressing. You can use 50% carbendazim WP at 0.5% of the seed amount, 30% Miaojundi WP, or a mixed dressing of 50% thiophanate-methyl WP at 0.6% of the seed amount and 75% 3911EC at 0.8% of the seed amount, with 2 to 3 kg of water per 100 kg of seed. Sunning the seeds. Before sowing, choose fine sunny weather and spread the cotton seeds out after opening the bags to sun them for 2 to 3 days.

Land preparation. When choosing land for planting cotton, it is best to choose fresh land that has never grown cotton or rotation land; land that has been continuously cropped for many years should be avoided for continued cotton planting. The land determined for cotton planting should be deep plowed 25 to 30 cm to reduce surface pathogens and favor seedling emergence. Irrigate in advance to avoid overly late irrigation, which can lead to excessively wet soil and lower ground temperature, which is unfavorable for seedling emergence. Before sowing, harrow and level the land so that it reaches "even, level, loose, fine, clean and moist".

Rational fertilization. If seed fertilizer is used improperly, especially excessive nitrogen fertilizer and insufficiently decomposed chicken manure, it will affect the emergence rate of cotton seeds. Therefore, when fertilizing, apply sufficient base fertilizer, make sure manure is fully decomposed, and pay attention to the ratio of N, P and K.

Scientific sowing. The sowing date should be appropriate. In production, overly emphasizing early sowing and sowing too early before the average temperature steadily reaches 10°C to 12°C will result in "early but not complete". If cloudy and rainy weather occurs, the combined effects of low temperature and high humidity are even more likely to cause seed rot and sprout rot. Generally, when the daily average temperature steadily reaches 10°C, the 5 cm ground temperature under the film can reach above 12°C, so film mulching and sowing can begin. In southern Hebei, the suitable period for film-mulched sowing in normal years is April 20 to April 30.