Although rice is a thermophilic plant, the optimum daily average temperature during the flowering and filling stages is 25-28°C, and the maximum daily temperature is lower than 34°C. When the average temperature on the day is 30-32°C and the maximum daily temperature is above 35°C, pollen vigor will be reduced, the fertilization rate and seed setting rate will decrease, and the empty shell rate will increase. Under high temperature conditions, the duration of grain filling shortened significantly, which is the so-called high-temperature ripening, resulting in deterioration of grain plumpness and quality of rice grains, and an increase in the rate of alfalfa grains. High temperature induced leaf and grain premature aging is the root cause of high temperature maturation. Early-season rice and early-season rice variety (combination) with a growth period of about 110 days should be promoted in early rice culturing under high temperature. Using the shed floppy disk cold-resistant seedling technology, sowing from March 15 to March 20, and planting from April 10 to April 15. The use of one-time fertilization (re-application of phosphorus, potassium fertilizer) and intermittent irrigation of fertilizer and water management, promote the early emergence of seedlings fast, early earing, early maturation. Ensure that the panicles are harvested in mid-June and harvested on or about July 10 to avoid the heat damage in the midsummer to the full-flowering heading stage and the grain-filling stage. During mid-season and late-season rice cultivation, the planting time should be postponed. The heading date should be set at the appropriate temperature in the middle or late August. In particular, the widely promoted Liangyoupeijiu, flowering pollination and grouting are extremely sensitive to high temperatures, and they must avoid the high temperature and heat damage in early August. When middle rice and late rice of the first season meet high-temperature stress conditions, heat-resistant technology should be adopted to spray Bohua, gibberellin, etc., as the main ingredient, to increase pollen and stigma vigor, thereby increasing the fertility rate and fruiting. rate. In the case of high temperature during the grain filling period, the depth of irrigation in paddy fields should be appropriately increased to increase the water absorption capacity of the roots, increase the stomatal transpiration intensity, and reduce the leaf surface temperature. At the same time, spraying grain satiety increased leaf photosynthesis and grain vigor, delayed leaf and grain senescence, and improved seed setting rate and fruit filling rate.
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