Effects Of High-temperature Forced Maturity Disaster To Early Rice In Jiangxi And Defense Technology

Jiangxi province is one of the important rice production areas in Yangtze river basin, rice planting area and output are the second in the nation. Early rice filling stage is in late June and early July, up against the high temperature period, vulnerable to heat damage, lead to high temperature forced maturity disaster, caused the decrease of yield and quality. Therefore, to master the heat damage occurrence rules of early rice in jiangxi province at high temperature stage, discusses the measures to defense heat injury at filling phase, to improve the quality of the early rice yield, enhance food security is of great significance.In this paper,using the cumulative departure and the information distribution methods to analyse the observatory meteorological data from 1961 to 2015 of 82 meteorological stations in Jiangxi province, to explore the early rice heat injury at filling phase and its influence on the rice yield in Jiangxi province. Then, discussed the influence of irrigation and foliar spray treatments to rice physiological ecology,field and quality. The main results were as follows:1、the critical period of the high-temperature forced maturity disaster to early rice is on June 15 to 20 July; 6-7 monthly average temperature change in 50 years in jiangxi province can be divided into 4 process, in which the temperature rise obviously and heat injury increased significantly since the new century; More heat injury occur in the stage for July 11-20, less for June 15 to 30, at the same time, the heat injury has a trends in advance after 2004 years; The large risk areas of heat injury was located in Jitai basin、Zhangshu、Xingan、Ganxian、Nankang at Gan jiang and Yingtan、Guixi at Xin jiang river basin, less area at the mountainous area. The number of heat injury at filling phase has a significant negative influence to actual early rice yield and meteorological yield, show that heat injury at filling phase are important factors which influence the production of early rice.2、The leaf temperature of all treatments was lower than the air temperature, and much more obvious with time extension, in which, B1 and B2 were lower than CK. This indicated that the treatment which irrigation during the day and drainage at night was helpful to reduce the leaf temperature at Filling stage of high-temperature seasons. The treatment which irrigation during the day and drainage at night keep 4-5 cm depth of water can increase the leaf chlorophyll content, leaf net photosynthetic rate, stomata conductance, and the apparent quantum efficiency, reduce the rice light compensation point, eventually improve photosynthetic ability significantly; And can increase the early rice yield through increase 1000-grain weight, increase the Spike grain number and grain crude protein and crude fat content, lower crude fiber, improve the nutritional quality and palatability.3、The leaf temperature of all treatments was also lower than the air temperature at filling stage of high-temperature seasons. And show the law of CK>A1>A2, and much more obvious with time extension, indicated that the spray treatment was helpful to reduce the leaf temperature at Filling stage of high-temperature seasons; The A1 treatment(spray 100kg/mu) can increase the leaf chlorophyll content, delay the inhibitory effect of high temperature on chlorophyll. Two treatments can increase leaf net photosynthetic rate, stomata conductance, intercellular co2 concentration、apparent quantum efficiency and so on, reduce the rice light compensation point and transpiration rate, and A1 processing have more significant effect, more lasting impact.4、At filling stage in high temperature season, spray 100 kg/mu can make the early rice 1000-grain weight increased significantly, increase the early rice yield. And make rice quality improved obviously than control at the same time. The whole polished rice rate was significantly increased by 15.23%, the chalkness rate and grain chalkness was reduced 40% and 52.24% than control, respectively, amylose content increased by 4.8% than control, but also reduce the Setback value level.