Rice empty grains are empty grains that are not refined and half empty grains that cannot develop after fertilization. This is a common physiological obstacle in rice production. In normal climate and cultivation conditions, the rate of empty grains of rice is about 10-20%. However, in abnormal years, empty grains can reach 30-40% or even higher, which has a great impact on rice yield. Therefore, in addition to fighting for multiple panicles and spikes in rice production, it is also necessary to reduce empty grains, increase seed setting rate, and increase grain weight to achieve high yields. Now we introduce the reasons for the occurrence of empty crumbs and their prevention and control measures for reference. First, the cause of empty grains is rice milling caused by the more complex reasons, in general, there are two internal and external causes. 1. Internal Causes The formation of internal causes of rice empty shells generally occurs in two situations: First, incomplete development of female and male organs before heading, and the fertilization process cannot be completed, resulting in the formation of empty shells. The second is when heading flowers, male and female organs can not be coordinated, can not be subject to powder and empty shells. The internal cause of pod formation is mainly due to malnutrition of the grain in the panicle, resulting in the ovary or endosperm stopping development and causing pods. 2. The external causes of the formation of rice empty grains are complex, with climatic conditions and cultivation conditions. In terms of climatic conditions, meteorological factors such as temperature, humidity, light, and wind have a great influence on the formation of empty plutonium. The optimum temperature for heading and flowering of rice is 25-30°C. At temperatures below 20°C, the fertilization process cannot be completed and empty shells are formed. However, when temperatures above 35°C are encountered, the fertilization process will also be adversely affected, and the empty shell rate will increase significantly. Illumination has a greater influence on the formation of empty grains. Since more than 95% of the dry matter in grains is derived from photosynthetic products, during the period of heading and fruiting, more rainy days and less sunshine will increase empty grains. Humidity and wind speed also have an impact on the formation of empty pods. The optimum humidity for rice flowering and fertilization is 70-80%, and the climate is too dry to be adverse to fertilization and easy to form empty shells. However, heavy rain or continuous rain during flowering, and excessive humidity, can also affect fertilization and seed formation and empty grains. In addition, improper cultivation conditions can also affect the formation of empty grains. The excessive application of nitrogenous fertilizer during the spikelet differentiation stage resulted in high nitrogen content in the leaves, which was not conducive to the accumulation of nutrients, and increased empty grains. Nitrogen deficiency in the earing stage and premature failure of heading leaves will also increase empty grains, leading to reduced yield. In addition to nitrogen fertilizers, the lack of phosphorus and potassium nutrition during rice growth will also affect the decline of photosynthesis and physiological function, and increase empty grains. In terms of irrigation, such as heading and flowering lack of water, resulting in poor fertilization, will increase empty grains. Poor drainage of paddy fields or long-term deep water irrigation may cause black roots, and the middle sun drying time may be too long or too heavy, and the late water cut may lead to premature senescence and increase empty grains. Close planting is unreasonable, the closure of the line is premature, ventilation and light transmission are poor, or damage by pests and diseases, and prevention and treatment are not timely, it will also increase the number of open space, resulting in serious reduction in production. Second, prevention measures To prevent the development of empty grains and achieve high yields, comprehensive preventive measures must be taken. 1. The physiological form of the rice varieties with good fruiting characteristics is different, and the seed setting rate varies greatly. Generally strong resistance, wide adaptability varieties, high seed setting rate. In terms of production, cold-resistant or heat-resistant, resistant to lodging, earing, and premature senescence should not be used. Varieties that are resistant to pests and diseases should encounter adverse environmental conditions to reduce the impact and ensure a high seed setting rate. 2, appropriate sowing and transplanting, avoid high and low temperature damage to local conditions, arrange seasons, early maturing varieties are not easy to sow early, in order to avoid the low temperature during the ear, increase empty grains. Late rice should not be planted too late so as to avoid affecting the low temperature in later stages. 3. Reasonable fertilization, irrigation, raising the seed setting rate should be closely planted, scientific water, prevent premature closure, affect ventilation and light transmission, and late greediness, premature aging, resulting in malnutrition, so that the formation of rice grains to create a good condition , thereby increasing the seed-setting rate and prompting grain filling. 4. Emergency measures shall be taken in time to reduce loss of rice from booting to heading and flowering. If high or low temperatures are encountered, defensive measures shall be taken promptly to reduce the damage and increase the seed-setting rate. Early rice during the booting stage or the late rice heading and flowering period, in case of low temperatures below 20°C, deepwater insulation should be promptly filled with good results. For example, the application of a warmer at the same time in the deep water is better. Early rice heading and popping flowering period meets the high temperature above 35°C, and daily deepwater irrigation can be used to cool the night row, and the temperature can be appropriately lowered to increase the relative humidity, which will help improve the seed setting rate. 5, top dressing can be sprayed phosphorus, potash fertilizer. In the presence of high temperature or low temperature, spraying 3% of superphosphate solution or 0.2% of potassium dihydrogen phosphate solution outside the root can enhance the rice plant's resistance to high and low temperature, and it can increase the seed setting rate and increase the grain weight. China Agricultural Network Editor
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