Main technical measures for rice seedbed management

Rice has entered the critical period of nursery bed management, and strengthening nursery bed management plays a vital role in cultivating strong seedlings and ensuring a bumper harvest of rice.

1. Regulate the membrane temperature. Before sowing to standing needle, the main task of seedling bed management is to promote seedling emergence and whole seedling. When sowing in early spring, the external temperature is low, in temperature management, mainly sealed film insulation. After sowing, always check whether there is dew seed or dew wind. If there is dew seed or dew wind, you should cover the soil cover seed and seal the film in time. Before emergence, the temperature in the film should be controlled at 30 ℃ 32 ℃. During the period from emergence to 1.5 leaves, the daytime temperature in the film should be controlled within 25 ℃. After uncovering the film, if the average daily temperature is more than 20 ℃ degrees Celsius, the seedbed should also take shading and cooling measures.

2. Uncover the film with vertical needle. The purpose of sowing and covering with plastic film in early spring is to increase temperature and preserve soil moisture and promote early emergence and full emergence of seedlings. But early uncover the film, in the place of low temperature, the seedling grows slowly, even rigid seedlings; late uncover the film, with the rise of air temperature, the temperature in the film is high, the seedling grows only, the resistance is poor, and the first leaf node is difficult to tiller. In general, the best time to uncover the film is 5-7 days after sowing, before the first complete leaf is unfolded (needle-like, about 2 cm). On the day when the film is uncovered, if the air humidity is high and the temperature is low, the film should be uncovered in the morning; if it is sunny, the film should be uncovered before the evening.

3. Pour the film water thoroughly. While uncovering the film, we must uncover the film, water it at the same time, and water it thoroughly. Because the air temperature around the seedlings rises sharply after the film is removed, and the water absorbed by the roots is often unable to supply, it is easy to cause green and dead seedlings. Therefore, timely watering and uncovering the film water, in order to supplement the lack of soil moisture after uncovering the film, so that the seedlings can adapt to the changes of the environment as soon as possible.

4. Replenish "weaning" water. At the stage of 2-3 leaves, the tolerance of seedlings is the worst, the time from leaf rolling to death is the shortest, and it is the most sensitive to water deficit. This period is also the most critical period to prevent and control dead seedlings and improve the seedling rate. If the film water is insufficient, the evaporation is too much, and the soil moisture is poor, the "weaning" water must be irrigated in time.

5. Moderate chemical control. In order to promote tillering and dwarf seedlings, the long-aged seedlings were sprayed with 250-300ppm paclobutrazol solution mixed with iodine alginate at the stage of 1 leaf, 1 heart and 3 leaves, respectively, in the seedling bed without seedling strengthening agent.

Flood and drought control after 6 and 3 leaf stage. After the third leaf stage, the seedling body is larger, the root system is gradually developed, generally can not be irrigated at will, should be mainly controlled by water dry cultivation, to prevent the excessive growth of water. In case of high temperature and drought, the leaves wilt and "reel" at noon, and the leaves do not unfold at night, they must be watered in the evening. But the amount of water should not be large, the number of times should not be too much.

7. Pour thoroughly the "wedding water". In the evening the day before planting, 1% urea solution was used to send marriage water and fertilizer at one time. This time, the use of water is very fastidious, not only an appropriate amount, not too much or too little, but also timely, not too early or too late, so as to achieve the goal of pulling seedlings effortlessly and not destroying the roots as much as possible. After transplanting, iodine alginate was sprayed as soon as possible to promote root healing and growth.