Effects of Water Stress of Soil on Rice Yield and Quality

Using Nongda 3 as a material,the effects of soil water stress(soil water potential) on the development,grain yield and quality of rice plants through pot experiment by manual rigorously controlling soil potential with tensionmeter were studied.The results indicated that the yield and quality were affected in different degree when the soil water potential(SWP) reduced to-75 kPa during the different growth periods.The lengths of three leaves from the top,grain number per panicle,biomass and grain yield of the plant,rate of brown rice,length/width of the kernel,and taste for eating decreased by water stress at middle booting stage.The panicle number,biomass and grain yield of the plant reduced by soil water stress at the beginning of tillering period.The leaf turned to shrink and yellow,and leaf area index declined because of soil water stress after heading.Meanwhile,the percentage of ripened grain,1 000-grain weight and head rice rate decreased by soil water stress at the milk and filling stages.The percentage of chalky grain and chalkiness increased at the filling stage,and the chlorophyll content,gel consistency and protein content were declined at the wax period.