Detailed Explanation of Rice Seedling Raising with a Separation Layer and Seedling Broadcasting Cultivation Technology

Rice seedling raising with a separation layer and seedling broadcasting is a new type of seedling broadcasting technology developed on the basis of soft-tray seedling raising and broadcasting. In addition to all the advantages of soft-tray seedling raising and broadcasting, it also has advantages that soft-tray seedling raising and broadcasting cannot match:
First, it can reduce costs more effectively, requires no special soft trays, and uses readily available materials.
Second, it can improve labor efficiency, reduce labor intensity, make sowing more convenient and quicker, and allow the seedlings to be pulled up as a whole sheet and transported in rolls.
Third, it can effectively overcome the seedling-age limitation brought by soft-tray seedling raising, increase the flexibility of seedling age, improve seedling quality, ease labor shortages, and allow late-maturing varieties to be selected for both early and late seasons, thereby effectively increasing rice yield per unit area and achieving a bumper harvest in both seasons. It generally increases yield by 100--200 kg compared with soft-tray seedling raising and broadcasting.
Fourth, it can save seeds and avoid the problems of difficult sowing and inability to sow evenly in soft-tray seedling raising. In short, it is a seedling broadcasting cultivation technology that is easier to operate, more flexible, and has greater yield-increasing potential than soft-tray seedling raising. Its key technologies are as follows:
I. Material preparation: Separation-layer seedling raising and broadcasting does not require soft trays, but materials for the separation layer must be prepared. Generally, fresh single-layer woven bags with good toughness or high-density, high-toughness, fine-mesh plastic gauze are used as the separation layer material.
II. Seedbed selection: The seedbed should be selected from vegetable garden land or dry land with fertile soil, loose and breathable texture, convenient irrigation and drainage, shelter from wind and sunny exposure, easy management, and no rodent damage.
III. Seedbed land preparation and bed making: The seedbed should be leveled according to the standard width of 1.5 m and length of 8--10 m, made into beds, and given base fertilizer. Apply 25--30 kg of compound fertilizer per mu, directly broadcast on the bed surface. The seedbed area is generally 1-1.5 times larger than that for soft-tray seedling raising, that is, for every 667 sq m of field, a bed 15--20 m long is prepared, so as to cultivate multi-tillering strong seedlings and improve seedling quality. After the seedbed is leveled and fertilized, place the separation layer flat on the bed surface, then evenly spread mud mixed with seedling-strengthening agent or pond mud on the separation layer to a thickness of 2--3 cm. After this is done, sowing can begin.
IV. Sowing: Generally, the seeding rate per mu of field should be controlled between 0.75--1 kg. Select late-maturing, high-yield, high-quality hybrid combinations. For early rice, sow as early as possible when the temperature stabilizes above 10°C; for late rice, sow before early June. After the seeds are germinated by normal methods, they can be sown on the prepared seedbed. Cover early rice with film and late rice with rice straw. When sowing, first sow 2/3, then use 1/3 to fill gaps, striving for evenness.
V. Seedling field management: The management of separation-layer seedling raising is basically the same as normal seedling field management. For early rice, pay attention to heat preservation, moisture retention, and timely ventilation and hardening of seedlings; for late rice, pay attention to preventing high-temperature damage to sprouts. At the one-leaf-one-heart stage, spray 50--60 g of paclobutrazol per mu mixed with 45 kg of water to promote tillering and cultivate multi-tillering short strong seedlings. Because separation-layer seedling raising is not limited by fertility, early rice can be broadcast at seedling age 25--30 days, and late rice can be broadcast at seedling age 30--45 days.
VI. Seedling pulling and broadcasting: For separation-layer seedling raising, 5--7 days before pulling seedlings, apply farewell fertilizer and spray farewell pesticide. For the farewell pesticide, spray 0.5% potassium dihydrogen phosphate solution plus 26% tricyclazole 500--600 times solution. After spraying, let the seedbed dry and then pull the seedlings. When pulling seedlings, they must be pulled up as a whole sheet along the separation layer or transported in rolls to the field for broadcasting. When broadcasting, they can be broadcast seedling by seedling, or the seedlings can be separated one by one, placed into tools, and broadcast handful by handful. The field for seedling broadcasting should be level. For sandy fields, level the field and broadcast on the same day; for muddy fields, broadcast the next day. First broadcast 2/3, then use 1/3 to fill gaps. For small fields and terraced fields, stand on the field ridge and broadcast; for large fields, set up walking paths every 3 m per bed and 30 cm for broadcasting. After broadcasting is completed, proceed to normal field management.
Precautions:
1. The separation layer should use fine-mesh material with good toughness to facilitate operation.
2. The seedling-strengthening agent must be mixed evenly, and the dosage must be controlled. The amount used on the bed surface per mu of field is 2.5--3 kg. The mud layer must not be too thin or too thick.
3. When pulling seedlings, the seedbed should be moist but slightly dry to ensure the integrity of the whole sheet of seedlings and prevent scattering, so as to facilitate transport and broadcasting.