Effects Of Weak Light And Effect Of Nitrogen Fertilizer Management Stress On Yield And Quality Of Double Cropping Rices

This study based on that the relationship between effects of light and nitrogen′s sensitivity difference and production stability which was cleared in 2014,with two stable types,two unstable types of double rice varieties(late rice was two type of varieties in 2016)as materials,through different stages of shading to study the characteristics of growth,production and the formation of rice quality in different types of double rice.With a type of stable early rice varieties and an unstable late rice varieties as materials in 2016,through nitrogen regulation and weak light stress treatment to study double rice′s dry matter production,yield and the formation of rice quality.The main results are as follows:Under shading at different stages,each stage of dry matter production decline,a significant reduction in yield,stable type and unstable type varieties in each stage of dry matter production and yield formation exists differences.Under the medium term shading,unstable rice’s yield decreasing range was higher than that of stability.Had a greater influence on rice when on the later shading,antioxidant enzymes active volatility is higher,the effective panicles,grain number per panicle,little change,total amount of spikelets haven’t changed much,have no obvious effect on capacity,nitrogen metabolism enzyme activity decreased,dry matter accumulation were decreased in mature period,leaf area index had no significant change,the source organ photosynthate production and supply of the late fall,severely reduces the seed setting rate and 1000-grain weight,the biggest cuts,harvest efficiency and utilization rate of nitrogen fertilizer was lowest.The different period of duration of the early and late rice in the double season under shading,the roughness,polished rice rate,whole refined rice rate and amylose,gel consistency,chalky rice percentage and chalk white degree have varying degrees of decline.Early and late rice in the double season under latter shading,grain filling of rice was decreased,leaf and stem sheath to grain transportation photosynthate decreased,significantly reduced the rice quality index,the late weak light have the greatest effect on rice quality.Under different stages of shading,the improvement of appropriate n application rate,the effective panicles significantly improve,increase grain number per panicle,total amount of spikelets increase,storage capacity is increased,promoted the mature period of dry matter production,stem sheath,leaf source organs to grain transport matter increase,seed setting rate and thousand seed weight shows significant rise,the source,library coordinated,and a marked increase in the production.Under the weak light,the increase of the amount of nitrogen in the unstabilized rice′s yield was significantly higher than that of the stable rice′s yield.The increase of the amount of nitrogen was not significantly raised in the rice harvest index,the partial productivity significantly decrease,the utilization of nitrogen fertilizer and efficiency was decrease.Under different stages of shading,increasing n application rate,which can effectively increase the source and sink,to promote grain photosynthate transportation,improve the appearance quality and milling quality of rice,cooking and eating quality,to a certain extent,compensate for the effects of weak light on rice quality.