Effects Of Warming,Moisture And Nitrogen Fertilizer On The Yield And Greenhouse Gases Emission Of Rice-wheat Rotation System

This paper studied the effects of temperature,moisture and nitrogen application on growth,yield and photosynthetic efficiency of winter wheat and rice using Yangmai 11 and Hanyouxiangqin as experimental materials.Two levels of temperature?warming and normal temperature?,two levels of moisture?decreased irrigation and normal irrigation?,and three levels of nitrogen?urea?application?pure nitrogen amount of winter wheat:208kg/hm²,416 kg/hm² and 624 kg/hm²,pure nitrogen amount of rice:140kg/hm²,280kg/hm² and 420kg/hm²?were selected and arranged in asplit-plot experimental design.Some indexes were surveied including plant height,biomass?whole panlt,grain and stalk biomass?,fv/fm,?_PS?and greenhouse gases emission fluxes.The main conclusions of this research were shown as follows:1.Warming increased the plant height,decreased aboveground biomass?including straw biomass and grain yield?and root biomass of winter wheat,but the reduction percentage of the aboveground biomass treated by 416kg/hm² nitrogen application was relatively samll;Warming also reduced the grains per panicle of winter wheat,1000-gain weight and ineffective tillers,and the grains per pancle decline percentage of winter wheat treated by 416kg/hm² nitrogen application was the minimum,however warming increased the number of total tillers,and the interaction between temperature and nitrogen application had a significant influence on winter wheat grain yield.2.Warming increased plant height of rice,and the increasement rate increased with nitrogen application,however,the influence of warming on rice yield was obviously different in 2014 and 2015,warming increased the rice yield with normal irrigation treatment in 2014,comparing with normal temperature,the grain yield of rice with 140 kg/hm²,280 kg/hm²and 420kg/hm² nitrogen application respectively increased by 860.7kg/hm²,2284.8kg/hm² and 2394.4kg/hm²,the increments were 10%,24%and 25%.However warming had no significant effects on rice grain yield in 2015.The 1000-grain weight of rice decreased markedly with the increase of nitrogen application under the treatments of warming and normal irrigation,but the number of panicles per square metre showed an opposite tendency obviously.3.Warming decreased the photochemical efficiency(?_PS?)and light energy transforming rate?fv/fm?of winter wheat and rice with different degree.4.The CH₄ emission fluxe of paddy under normal irrigation treatment was higher than intermittent irrigation during heading,grain filling and mature stage,especially marked in heading and mature stage;the CH₄emission fluxes of paddy with warming treatment showed a decreasing tendency comparing with normal temperature.The N₂O emission fluxe with intermittent irrigation treatment was generally higher than normal irrigation,and the N₂O emission fluxe of paddy showed an increasing trend under warming treatment.As with CO₂ emission flux of paddy,the effects of warming and irrigation on it had great uncertainty.