Technical specification for dry raising and throwing seedlings in plastic trays for growing rice

According to different stubble, variety characteristics and safe heading stage, the varieties with high quality, high yield, stable yield, strong tillering ability and good stress resistance were selected. There are mainly early-maturing and late japonica rice varieties along the Yangtze River and southern Jiangsu, with late-maturing medium japonica rice varieties. Nanjing 44, Ningjing 3, Yangjing 4038, Wuyunjing 23 and Zhendao 11 were selected for early maturing late japonica rice, while Wuyunjing 24, Huidao 13 and Huidao 9 were selected for late maturing middle japonica rice. In central Jiangsu and Lixiahe areas, there are mainly late-maturing middle japonica rice varieties, with mid-maturing middle japonica rice and early-maturing late japonica rice varieties. Lianjing 7, Xudao 3 and Wuyunjing 21 were selected as the key varieties of medium-maturing japonica rice. Along the Huaihe River and Huaibei region, there are mainly medium-maturing medium japonica rice varieties, with late-maturing medium japonica rice varieties.

The standard seedlings of strong seedlings are neat, the seedling age is 30 ~ 35 days, the leaf age is 5.5 ~ 6.5 leaves, the seedling height is 13 ~ 18 cm, the diameter of basal stem is 0.35 ~ 0.45 cm, the number of green leaves per plant is 4.5 ~ 6, the number of white roots is 12 ~ 18, the number of tillers is 0.5 ~ 1, the dry weight of 100 plants is about 7.5 grams, and there are no diseases and insect pests.

20 days before the seedling was prepared for sowing, urea and 45%BB fertilizer were applied each 30 kg per mu of seedling field, and ploughed in time after fertilization. The seedling bed is required to be 140 cm wide, 25 cm wide and 20 cm deep, with matching internal and external ditches to ensure smooth drainage. About 20 days before sowing, 250 kilograms of nutritious soil per mu should be prepared on a sunny day, and the nutritious soil should be disinfected. The seeds were insolated, screened and sterilized, and every 5 kg of rice seeds were treated with 25% prochloraz EC 2 ml plus 4.2% dithiocyanomethane EC 2 ml, or 16% chlorphenamine EC. Shamindan wettable powder 15 grams, soak for 60 hours with 9 kilograms of water for 72 hours, sow directly without accelerating germination, or directly sow seeds with "dry nursery nanny" after seed coating. There are about 55 seedling plates with 434 holes in each mu of field. According to the seedling field ratio of 1 ∶ 35, prepare a sufficient seedling bed.

The sowing date is determined according to the suitable throwing seedling age of 30-35 days. The sowing date is generally on May 15-25 in Huaibei area, May 10-20 in Central Jiangsu and May 5-15 in Southern Jiangsu.

Before the sowing procedure, the seedling bed is watered enough, the two rows of the seedling plate are pasted horizontally, the plate is close to the plate without leaving a gap, and the bottom of the plate is closely integrated with the bed surface. Use fertile soil as seedling soil and sprinkle it evenly into the plate. After sowing, the bed was fixed and the seeds were sown evenly, with 3-4 grains per hole. Cover the seeds with unmixed nutritious soil until the holes are full. If possible, watering can be used to pour through water, and if furrow irrigation is adopted, quick irrigation and rapid drainage should be adopted. After the seedling water dries, surround the seedling tray with mud, then cover with plastic film or non-woven cloth, and then cover with wheat straw to maintain a light transmittance of 10% to 15%. Film mulching (non-woven cloth) does not need irrigation during the grass mulching period, and the stagnant water in the seedling field can be eliminated in time on rainy days.