The latest course of Rice Seedling Management techniques and methods

Nursery bed temperature management

The main results are as follows: 1. After sowing, the dew tip of the first leaf is dominated by heat preservation. The temperature in the greenhouse is 28-30 ℃, the optimum temperature is 25-28 ℃, the 2-leaf stage is 25 ℃, the 3-leaf stage is 20-22 ℃, and the lowest temperature is not less than 10 ℃. If the temperature is low at night, measures such as turning on the electric light in the greenhouse or burning rice husks should be taken to increase the temperature, and those raising seedlings in the small shed should cover straw or cold-proof quilts outside the shed to increase the temperature, so as to ensure that the minimum temperature index for each leaf age of the seedling can be achieved. so that rice seeds can grow and develop normally on the seedling bed.

2. Ventilation management of seedbed. After the emergence and greening of rice seedlings, the plastic film should be removed, and it is best to uncover the plastic film in the morning or evening. The temperature difference inside and outside the shed is small, and the seedlings can adapt to the new environment quickly. If the mulch is uncovered when the temperature is high at noon, the water transpiration of the aboveground seedlings is fast, and the root absorption is slow. It is easy to cause physiological water loss of seedlings. After uncovering the plastic film, small ventilation can be carried out, and the ventilation reaches the lowest temperature limit of each leaf age, and the shed should be closed in time. With the increase of leaf age, the time of ventilating seedlings is prolonged accordingly, especially in 2.5leaf stage, the temperature should not exceed 25 ℃, and the temperature should be higher than 25 ℃. It is necessary to cool down by ventilation to prevent early heading. The temperature inside and outside the shed is close to the same after the 3-leaf stage, and if there is no frost at night, there is no need to cover the film and wait for transplanting.

Nursery bed moisture management

1. In the case of pouring through the bottom water, in principle, try not to water before 2 leaves, and the water of the seedling bed should be watered three times in the future: first, whether there are dewdrops on the leaf tip in the morning and evening; second, whether the newly unfolded leaves are curled at high temperature at noon; third, whether the soil surface of the seedbed is white. If the leaves do not spit in the morning and evening, the newly unfolded leaves are curled at noon and the surface of the bed soil turns white, the warm water in the morning should be fully watered and thoroughly watered as much as possible, let alone irrigating the bed with cold water, which will lead to cold water stiff seedlings and affect the growth and development of rice seedlings.

2. Try to grow seedlings by drought, grow seedlings by water and grow roots by drought. If you want to have a good seedling root, you must control the moisture in the seedling bed. Seedlings can promote root development only under dry cultivation, especially 2-3 days before transplanting, it is best not to water the roots of seedlings to maintain dry cultivation. If the roots of the seedlings are not good before transplanting, more roots can be applied 1-2 days before transplanting, which can make the rice seedlings have more roots, more white roots, longer roots and better roots.

Controlling seedling growth, dwarfing and promoting tiller

The key to cultivating strong seedlings is to control overgrowth. Paclobutrazol can inhibit seedling growth, promote tillering, increase chlorophyll content, enhance enzyme activity, facilitate metabolism and enhance drought and cold resistance. Practice has proved that 15 days after seedling emergence, spraying with 0.2-0.3 grams of 15% paclobutrazol per square meter has a good effect on dwarfing and promoting tiller. Strong seedling standard: seedling age 30-35 days, leaf age 3-3.5 leaves, seedling height 12-14 cm, root number per seedling 9-11, stem diameter 2.5-3 mm, 100 plant dry weight 3-3.5 g, tillering rate more than 30%.

Prevention of bacterial wilt and bacterial wilt of rice at seedling stage

According to the cold and hot weather conditions in late April, seedling diseases are easy to occur.

The main results are as follows: 1. Rice blight is mainly caused by many factors, such as low temperature and humidity, large temperature difference, alkaline soil, lack of light, excessive sowing rate, weak seedlings and so on, which seriously affected the improvement of rice seedling quality and rice yield per unit area. Therefore, comprehensive control measures must be taken to prevent the occurrence and spread of rice blight.

2. Rhizoctonia solanacearum is a fungal disease, which can be divided into three types: bud rot, basal rot and yellow blight. Ralstonia solanacearum is a physiological disease, which mostly occurs after the three-leaf stage, the leaf is green, the leaf tip is free of water, rolled, the heart leaf is drum-shaped, and when it is serious, the whole rice seedling dies.

3. Prevention and control measures

(1) Prevention and control of blight. Do a good job of seed and bed soil disinfection, control the temperature and humidity of the seedling bed, cultivate strong seedlings, and improve the disease resistance of seedlings. When the disease occurs in seedlings, the application of Likukexin mixed with iodine alginate can effectively control the disease.

(2) Prevention and control of bacterial wilt. Reducing the sowing rate and advocating the application of isolation layer to raise seedlings can increase the ground temperature; when ventilating seedlings, attention should be paid to blocking it with woven fabric under the opening of the greenhouse, so as to avoid withering directly caused by strong wind. When the disease is relatively serious, irrigation on the bed, after the leaf unfolds, immediately discharge the water; serious disease with Ruimiaqing water agent, spray 1 ml per square meter, can be cured.

Achieve "three belts" before transplanting seedlings and carry out fitness cultivation

Before transplanting seedlings, we should do a good job of "three belts" of seedlings: one belt of soil can ensure the quality of transplanting seedlings, which is conducive to the rapid green survival of seedlings; the second belt of fertilizer, applying 150g diammonium phosphate per square meter seedling bed, and then watering and washing seedlings can promote the development of root system; three-belt medicine, every 100square meter seedling bed with 4 grams of ambroxol and water spray seedling bed to prevent leaf miners, while spraying 75% tricyclazole or 1500 times of Tianfengsu liquid fitness cultivation. Early soil preparation, early transplanting and early transplanting can grab the active accumulated temperature of more than 20 ℃, which is beneficial to rice ripening before frost.