Detailed Explanation of Key Cotton Sowing and Seedling-Raising Techniques

I. Prepare the seedbed early. Choose a disease-free plot that is sheltered from the wind and faces the sun, with higher terrain, convenient drainage and irrigation, and a low groundwater table as the seedbed.

II. Apply sufficient seedbed fertilizer, mainly organic fertilizer, with an appropriate amount of phosphorus and potassium fertilizer added, truly achieving a scientific formula. If a three-element compound fertilizer is used as seedbed fertilizer, it must be applied in an appropriate amount. When applying fertilizer, mix it thoroughly to truly achieve the goal of both fertilizing the soil and nourishing the seedlings. At the same time, apply little or no urea or ammonium bicarbonate to prevent root burn and seedling death during emergence or excessive vegetative growth of cotton seedlings, which would lead to weakened disease resistance, underdeveloped root systems, and a prolonged recovery period after transplanting, resulting in stunted seedlings that fail to grow.

Do a good job of sunning and selecting seeds

Before sowing, take advantage of sunny days to sun and select seeds. Sunning seeds can break seed dormancy and improve seed viability, which helps achieve full emergence in one sowing.

Effectively carry out the three soil disinfections

After the seedbed soil is prepared, make the pots in advance. Carry out the first disinfection one day before making the pots. First, add enough water to the seedbed soil, mix and level it. When making the pots, pour a 250-300 times dilution of mepronil or a 300 times dilution of quintozene onto the surface of the seedbed soil, or one week before making the pots, spray 150-200 grams of dexon per mu onto the surface of the seedbed soil for disinfection, then proceed to make the pots. After the pots are made, broadcast carbofuran to prevent @#@254@#@ from damaging the pots, then cover with agricultural film to prevent rain from washing away and damaging the pot bodies. When it is time to sow, carry out the second disinfection by spraying a 250-300 times dilution of mepronil onto the pot bodies, then sow. After sowing, cover with soil and cap, then carry out the third disinfection (same method as above). Do not use surface soil from cotton fields for the capping soil, because the surface soil contains a large amount of pathogenic bacteria. After emergence, promptly control seedling-stage diseases such as damping-off and rhizoctonia blight. At the same time, sun the seedbed to remove moisture, promote deep root growth, and ensure the cotton field is not infected by diseases.

Ensure timely sowing

As the saying goes, Qingming is too early, Lixia is too late, and emergence before Guyu is just right. The suitable sowing time is when the temperature is stable above 15°C, generally in early to mid-April (the 8th to the 20th), sowing on sunny mornings. Do not sow in March, because sowing too early means both air temperature and soil temperature are very low, with frequent cold waves. Although emergence is easy, keeping the seedlings alive is difficult, and a large number of dead and diseased seedlings will appear, bringing passivity to the whole year's production.

Pay attention to sowing quality

I. For sowing time, farmers must pay attention to the weather forecast and begin sowing when there are more than 3 consecutive sunny days. When sowing, sow while covering soil, and disinfect while covering film, to help the seedbed warm up. Do not sow on cloudy or rainy days. After 4 p.m., because the seedbed temperature cannot rise at night, it is best not to sow either. Practice has proved that with the same seeds, the emergence rate differs between sowing on sunny days and cloudy days, and the emergence rate also differs between sowing in the morning and after 4 p.m.

II. Adhere to "two wet and one dry" sowing, that is, wet pots, wet capping soil, and dry seeds. Make the pots first and then sow; do not make pots and sow at the same time, because inconsistent moisture and inconsistent temperature will lead to inconsistent emergence, which can result in incomplete and uneven cotton seedlings that are inconvenient to manage.

Scientifically manage the seedbed well

I. Promptly open ditches and raise the bed to prevent waterlogging in the seedbed. A dry seedbed helps cotton roots grow deep, cultivate a strong root mass, and improve disease resistance. Truly achieve root growth through dryness, root growth through warmth, and root growth through oxygen, cultivate a strong root mass, and lay the foundation for promoting early development of cotton seedlings.

II. Control the temperature inside the film well to prevent seedling burn. Before full emergence, keep warm and retain moisture; do not uncover the film. For double-film mulching, when the emergence rate in the seedbed reaches 70%, remove the flat-laid layer of plastic film around 8 a.m. on a sunny day. After full emergence, take advantage of sunny days to uncover the film and sun the bed, and spray once with half-strength Bordeaux mixture for disease prevention. From full emergence until before there is 1 true leaf, ensure the temperature inside the film is 20°C-30°C, and open both ends of the film to prevent high-temperature seedling burn.

III. Do a good job of moving pots for seedling hardening. After cotton seedlings have 1 true leaf, when they cannot be transplanted in time due to the previous crop, move the pots for seedling hardening to promote root growth and shorten the recovery period after transplanting.

Transplant strong seedlings

When the seedlings are 10-12 cm tall, have 3-4 true leaves, and white roots have filled the pots, they can be transplanted to the field with medicine and fertilizer.