Key Technical Points for Mechanized Micro-Pot Seedling Raising of Cotton

Traditional nutrient pot seedling raising methods have drawbacks such as high labor demand, complex seedbed management and high labor intensity during transplanting. The mechanized micro-pot seedling raising technology for cotton, developed by the Institute of Industrial Crops of the Jiangsu Academy of Agricultural Sciences and the Jiangsu Agricultural Technology Extension Center, breaks through the long-standing traditional model of cotton seedling raising relying on manual work and achieves the goal of saving labor and effort in cotton seedling raising. At present, the mechanized micro-pot seedling raising technology is at the experimental demonstration stage and has not yet been promoted and applied on a large scale, and farmers do not sufficiently understand and master the technology. For this reason, our newspaper's reporter interviewed Associate Researcher Zhang Peitong, a cotton cultivation research expert at the Institute of Industrial Crops of the Jiangsu Academy of Agricultural Sciences, about the advantages and disadvantages and detailed technical procedures of mechanized micro-pot seedling raising.

According to the introduction, mechanized micro-pot seedling raising technology is a seedling raising method that uses pot-making machinery to make micro-pots about 4.5 cm high and about 3.5 cm in diameter, and then sows cotton seeds into the nutrient pots. The advantages of this seedling raising method over traditional nutrient pot seedling raising are mainly shown in the following aspects: First, mechanical pot making is used, and the pot-making speed is fast, with 2500-3000 pots produced per hour, equivalent to the pot output of 5 hours of manual pot making. Second, the pots are small, the amount of nutrient soil used is low, and the seedbed is small, so more than 2 labor-days per mu can be saved in soil preparation and pot making. Third, the seedling raising period is shortened, and the cotton seedlings can be transplanted after film removal and hardening at the 2-leaf-1-heart stage, saving 1 labor-day per mu in seedbed management. Fourth, transplanting operation is simple and convenient, saving more than 2 labor-days per mu in transplanting. However, pot-making machinery is expensive (3000 yuan per unit), and for farmers with a small cotton planting scale the input cost is relatively large, which limits the development of mechanized micro-pot seedling raising technology. Accelerating research and developing small pot-making equipment suitable for individual households is an urgent task for the application and development of this technology.

The mechanized micro-pot seedling raising method is suitable for application in coastal areas where the soil is clay and loam. In areas where the soil is sandy, the pot formation rate is low, and traditional nutrient pot seedling raising is best used. Regarding transplanting survival rate and the seedling recovery period, as long as the seedling age is suitable and the cotton seedling quality is good, the transplanting survival rate and seedling recovery period can reach the indicators of traditional nutrient pot seedling raising. It is worth noting that the suitable transplanting seedling age for the mechanized micro-pot seedling raising method is 2 leaves and 1 heart, and exceeding the 2-leaf-1-heart stage is unfavorable for transplanting survival, so areas with later crop rotation should appropriately delay sowing.

Because mechanized micro-pot seedlings have small pots and a short seedling age, seedling management differs from traditional nutrient pot seedling raising. (1) Determination of sowing date. The seedling raising time should be appropriately delayed. For early crop rotation, the sowing date is around April 15, and for middle and late crop rotation, the sowing date is around April 25. (2) Sowing operation. After watering the seedbed thoroughly, sow 1-2 seeds per pot, cover with 1-1.5 cm of fine soil, and fill the gaps between nutrient pots. After sowing, spray the seedbed with herbicide, build a small arched shed 50-55 cm high, and clear the drainage ditches around the seedbed. (3) Seedbed management. From sowing until full emergence, use high temperature and high humidity to promote uniform emergence. Keep the shed film closed before emergence. After full emergence, seize sunny days to remove the film and sun the seedbed to reduce humidity, preventing cotton seedlings from shooting up into leggy seedlings and preventing diseases. When the cotyledons are flat, spray a broad-spectrum protective fungicide to prevent seedling-stage diseases. For seedbeds where guochuangcaojing has not been used, spray zhuangmiaosu to control height. During the seedling stage, control the seedbed temperature at 25-30°C. After the temperature rises, open the film at both ends and the ventilation holes to cool down, ensuring the cotton seedlings pass the night on a warm bed to promote rapid seedling growth. In rainy weather, cover the shed film well to keep warm. Remove the film 4-5 days before transplanting to harden the seedlings and control moisture to ensure the pots remain intact at transplanting. Transplant when the seedling age is 20-22 days and the cotton seedlings are at the 2-leaf-1-heart stage.