Management techniques of Rice Seedling stage

seedbed temperature management

1, after sowing to 1 leaf exposed tip, temperature to keep warm. The temperature in the shed is 28-30℃, the optimum temperature is 25-28℃, the second leaf stage is 25℃, the third leaf stage is 20-22℃, and the lowest temperature is not lower than 10℃. If the temperature is low at night, measures such as turning on electric lights or burning rice husks in greenhouses should be taken to increase temperature. For seedlings in small sheds, straw or cold quilt should be covered outside the shed to increase temperature, so as to ensure that the minimum temperature index required for each leaf age of seedlings is reached, so that rice seeds can grow normally on the seedbed.

2. Nursery bed ventilation management. After rice seedling greening, it is necessary to remove the plastic film, preferably in the morning or evening, the temperature difference between inside and outside the shed is small, the seedlings adapt to the new environment quickly, if the temperature is high at noon, the water transpiration of the aboveground seedlings is fast, the root absorption is slow, easy to cause physiological water loss of the seedlings. After removing the plastic film, small ventilation can be carried out, ventilation reaches the minimum temperature limit of each leaf age, and the shed should be closed in time. With the growth of leaf age, the time of ventilation and seedling tempering is prolonged correspondingly, especially in the 2.5 leaf stage, the temperature should not exceed 25 ℃, and the temperature should be lowered to prevent the occurrence of early ear phenomenon. After the 3-leaf stage, gradually large ventilation, the temperature inside and outside the shed is close to the same, if there is no frost at night, do not cover the film, wait for transplanting.

seedbed moisture management

1, in the case of pouring through the bottom water, in principle, try not to water in front of the 2 leaves, and then pour the seedbed water to do three things: see whether there is dew at the tip of the morning and evening leaves; see whether the newly unfolded leaves are curled at noon high temperature; see whether the surface of the seedbed soil is white. If the early and late leaves do not spit water, the newly unfolded leaves curl at noon, and the surface of the bed soil turns white, the warm water in the morning should be watered enough and thoroughly at one time, and the watering times should be reduced as much as possible, let alone cold water irrigation bed, which will lead to cold water stiff seedlings and affect the growth and development of rice seedlings.

2, try to achieve dry breeding seedlings, water seedlings, dry roots, to want seedlings to root well, must control the seedling bed moisture. Seedlings can only promote root development under dry conditions, especially 2-3 days before transplanting, it is best not to water the roots of seedlings to maintain dry. If the seedlings are not well packed before transplanting, they can be washed and applied 1-2 days before transplanting, which can make the rice seedlings have more roots, more white roots, long roots and good packing.

Control excessive growth of seedlings, dwarfing and promoting tillers

The key to cultivating strong seedlings is to control excessive growth. Paclobutrazol can inhibit seedling elongation, promote tillering, improve chlorophyll content, enhance enzyme activity, facilitate metabolism, and enhance drought resistance and cold resistance. The results showed that the effect of spraying 15% paclobutrazol 0.2- 0.3g/m2 on dwarfing and tillering promotion of seedlings was good. Strong seedling standard: seedling age 30-35 days, leaf age 3-3.5 leaves, seedling height 12-14 cm, root number 9-11 per seedling, stem diameter 2.5-3 mm, dry weight of 100 plants 3-3.5 g, tiller rate above 30%.

Prevention of rice seedling blight and bacterial wilt

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

1. Rice seedling blight is mainly caused by many factors such as low temperature and humidity, large temperature difference, alkaline soil, insufficient light, excessive sowing amount, weak seedlings and so on, which seriously affect the improvement of rice seedling quality and rice yield. Therefore, comprehensive control measures must be taken to prevent the occurrence and spread of rice seedling blight.

2. Rhizoctonia solani is a fungal disease, which can be divided into three types: bud rot, base rot and yellow rot according to different onset periods. Ralstonia solanacearum is a physiological disease, which occurs after the three-leaf stage. The leaves are blue, the tips of the leaves have no water drops, and the heart leaves are rolled. When serious, the whole plant dies.

3. Prevention and control measures

(1) Prevention and control of bacterial wilt. Disinfect seeds and bed soil, control temperature and humidity of seedbed, cultivate strong seedlings and improve disease resistance of seedlings. When the seedling disease occurred, application of Likuxing mixed with iodine alginate could effectively prevent and control seedling blight.

(2) Control of bacterial wilt. Reduce the seeding rate, advocate the application of isolation layer seedlings, can improve the ground temperature; ventilation seedling training should pay attention to the greenhouse opening with woven fabric, etc. to avoid wind directly lead to blight. When the disease is serious, irrigate the bed, wait for the leaves to unfold, immediately drain the water; when the disease is serious, use Ruimiao Qingshui agent, spray 1 ml per square meter, you can cure it.

"Three belts" before transplanting and body-building cultivation

Before transplanting, seedlings should be done well "three belts" work, one belt soil, can ensure the quality of transplanting, conducive to rapid rejuvenation of seedlings survive; two belt fertilizer, 150 grams of diammonium phosphate per square meter of seedbed, and then watering and washing seedlings, can promote root development; three belt medicine, every 100 square meters of seedbed with 4 grams of Emile mixed with water spray seedbed to prevent leaf miner, while spraying 75% tricyclazole or Tianfengsu 1500 times solution fitness cultivation. Advocate early soil preparation, early transplanting, early transplanting 1 day, can grab the activity accumulated temperature above 20℃, conducive to rice ripening before frost.