(1) Low temperature resistance measures. (1) When raising seedlings in greenhouse, ventilation should be reduced and delayed, grass curtains should be placed around the greenhouse, and plastic films should be laid in the greenhouse. The night temperature can be raised from 1: 00 to 2: 00 by means of pot fire or smoking. According to the weather forecast, the greenhouse should be covered with plastic film and sealed for heat preservation. In case of frost, you can light candles or smoke in the shed to increase the temperature and prevent freezing. (2) Strengthen seedbed management of frozen seedlings, irrigate with cold water before sunrise, and spread grass on the bed surface after sunrise to prevent strong light irradiation and excessive temperature rise from aggravating cold damage and avoiding high temperature covering seedlings; You can also spray humic acid organic fertilizer on leaves to strengthen seedlings and promote roots. When the concentric leaves are unfolded, they can be transplanted in time when there are 3 live leaves. (3) In case of low temperature during transplanting, deep water should be used to protect the seedlings and irrigation should be used to submerge the seedlings; Water-deficient plots should be lit at 2 pm on the windward side for smoking. (4) All localities should pay attention to the weather forecast, do not blindly transplant rice seedlings before the end of the final frost, and act according to law to avoid causing greater harm. ⑤ Chemical control measures. Foliar spraying of rice with Tongtianbao can enhance the ability of rice to resist low temperature stress. 1. Soak seeds with 2000 mg/kg common rice Tongtianbao (30 ml water 15 kg) before sowing; Or spraying universal rice Tongtianbao on the two leaves of 1 in the heart stage, and spraying 30 ml of rice Tongtianbao on 15 kg of water and 1 mu; Second, spraying universal rice Tongtianbao on the leaves at jointing stage, and spraying 30ml of rice Tongtianbao on 1 5kg water and1mu land; 3. During the filling stage (full heading stage), the leaves were sprayed with universal rice Tongtianbao, 30 ml of rice Tongtianbao, and 15 kg of water, 1 mu of land.
(2) Seedling management measures.
① Temperature management. In spring, the temperature in the rice seedling shed is generally low. In order to control the temperature of the seedbed, a thermometer should be set in the seedbed (below the highest tip of the seedling 1 cm) to observe the temperature. And check whether the seedbed condition is conducive to seedling emergence at any time. When the emergence rate reaches 80%, the film should be uncovered in time to prevent white buds and baked seedlings. Before 8: 00 and after 16: 00, the plastic film should not be uncovered in the middle time, and the temperature in each growth period should be strictly controlled.
Seed rooting period: the optimum temperature is 25 ~ 28℃, and the minimum temperature is not lower than 10℃. The temperature at 1 below the seedling tip at leaf stage 1 cm is controlled at 22 ~ 25℃, at 22 ~ 24℃ below the seedling tip at 2-leaf stage 1 cm, at 20 ~ 22℃ below the seedling tip at 3-leaf stage 1 cm, and at 3.1~.
② Water management. Generally, seeds are not watered during rooting. If water is found under the plastic film or the soil is too wet, peel off the plastic film during the day, evaporate the water as soon as possible and cover it at night. If it is found that the top cover is exposed or the bed soil turns white and lacks moisture, the top cover should be knocked off, and the exposed part should be properly covered with soil, supplemented with a fine nozzle watering can, then connected with the bottom moisture, and then covered with plastic film. Generally, little or no water should be watered at the leaf stage of 1, and the seedbed soil should be kept in dry field conditions. 2 ~ 3 leaf stage: water according to the "three views" to see whether the soil surface is white, whether the root system is growing, the size of the water droplets at the tip of the leaf in the morning and evening, and whether the new leaves are curled at high temperature in the afternoon. For example, the bed soil turns white, water drops become smaller in the morning and evening, or new leaves curl at noon. Before 8: 00 and after 16: 00, the temperature should be 16℃. 3. 1 ~ 3.5 leaf stage: control the moisture in the seedling field, squat down the seedlings and strengthen the roots, so that the seedlings are in a state of hunger and thirst.
③ Pest control. Low-temperature climatic conditions are conducive to the occurrence of low-temperature diseases such as cotton rot, bacterial wilt and rice damping-off.
Rice cotton rot occurred 5 ~ 6 days after rice sowing, which mainly harmed young roots and buds. Copper sulfate 1000 times liquid spray can be used to control rice and cotton rot.
Bacterial wilt usually occurs when the seedlings grow to the third leaf, so the seedlings should be ventilated and practiced. When the temperature is too low at night, cover the seedbed with a straw curtain to minimize the temperature difference between day and night. If bacterial wilt occurs seriously, it should be immediately irrigated or sent to other places. Pesticide control should be carried out in time for seedbeds with diseases. The recommended pesticide for controlling rice cotton rot can be sprayed with 25% metalaxyl wettable powder 800 ~ 1000 times per mu.
It is suggested that chemical agents should be used to control rice damping-off: a.30% water solution of Rui Miao, 3000 times of water, spraying 2 ~ 3 kg per square meter. B 97% hymexazol powder, with the dosage of per square meter 1g, is used for watering. C.35% chlorothalonil wettable powder 10g, and irrigate the seedbed for 30 ~ 45m after watering. D.50% Likujing wettable powder, per square meter of seedbed 1 ~ 1.5g, watered. E 2% ningnanmycin aqua, per square meter 12.5 ~ 25ml, sprayed with 2 ~ 3kg of water. F.2% good universal water agent, 5 ml per square meter, and an appropriate amount of water seedbed spray.
④ Chemical weeding. The seedbed is prone to herbicide damage at low temperature and high humidity, so high-safety pesticides such as cyhalofop-butyl, thiacloprid and dimehypo must be used for chemical weeding in rice seedbed. Herbicides such as phorate, cyhalofop-butyl, penoxsulam and pyrimethanil can be used to control barnyard grass and creeping bentgrass in rice.
⑤ Fertilizer management. A. master the scale of fertilization and balance the supply of nutrients. Fertilization amount should be in accordance with the conventional fertilization amount in previous years to avoid the phenomenon of increasing fertilization amount due to short seedlings, especially to control the problem of excessive nitrogen fertilizer consumption. In specific production fertilization, the ratio of phosphate fertilizer to potash fertilizer can be appropriately increased to alleviate the phenomenon of stiff seedlings caused by insufficient phosphate fertilizer nutrition, and the dosage of sulfur-based potash fertilizer can be increased to enhance the physiological activity of seedlings and improve the utilization rate of nitrogen fertilizer and rice disease resistance. B. Choose the varieties of foliar fertilizer correctly to promote the growth of seedlings. Because of low temperature, it may affect the growth process, and at the same time, high temperature may appear in the later stage, causing diseases and reducing the quality of seedlings. Therefore, it is very important to control the growth through foliar fertilizer and choose the varieties of foliar fertilizer. On the basis of strengthening seedbed management in production, humic acid foliar fertilizer is recommended, amino acid foliar fertilizer is not used or used cautiously, and single nutrition promotion behavior such as spraying urea water is put an end to. C. bring fertilizer to the field to reduce the time of turning green and extending seedlings. Within 3 ~ 4 days before transplanting, applying appropriate amount of urea plus diammonium topdressing or spraying 400 ~ 500 times humic acid foliar fertilizer under appropriate water control conditions can improve soil fertility, improve seedling nutrition and reduce seedling lag time. D. Pay attention to the use of trace element fertilizers to prevent physiological diseases. Cold-stiff paddy fields are prone to physiological diseases such as zinc deficiency at low temperature, which leads to seedling stiffness and affects tillering. Zinc sulfate fertilizer can be sprayed on seedlings 3 ~ 4 days before transplanting, or foliar fertilizer containing zinc fertilizer can be selected. In Honda, symptoms of zinc deficiency usually appear 20 days after transplantation. If the symptoms of zinc deficiency appear, you can directly spray zinc sulfate with potassium dihydrogen phosphate to relieve the symptoms.