Effects Of Sraw Returning And Water And Nitrogen Management On Yield Of Hybrid Rice Under Rice-rape Rotation And The Properties Of Soil

Straw resources in China,low utilization rate of Nitrogen（N）fertilizer,agricultural irrigation water resources shortage and uneven distribution,especially in rice cultivation waste water more severe conditions;To enriching the soil fertility,water conservation reduce N and high yield arid excellent quantity for ground rice,for the purpose of the straw returned and water-saving section fertilizer form a complete set of rice cultivation mode of high quality,is of great significance to the agricultural sustainable development.Therefore,this study was conducted in the 2017 and 2018,2 years of repeated experiments,the rape-rice planting mode,selection of wide applicability to high quality and high yield of super hybrid indica appropriate Yixiangyou 2115 as test material,the three factors of crack split plot design,the main area for rape straw returning heap corruption and returning directly 2kinds of straw returned,split block for"flooding irrigation"and"controlled alternate irrigation"two moisture management way,crack crack area of 4 kinds of n application(N₀:no N;N₁:75 kg hm^-2;N₂:150 kg hm^-2;N₃:225 kg hm^-2),the analysis of population quality,yield and grain quality of rice,and the influence of soil physical and chemical properties,the system was studied under the condition of different straw returning processing,irrigation methods and N application rate photosynthetic characteristics,yield and yield components of rice,rice quality and N use efficiency,and the influence of soil physical and chemical properties,analytical different straw returning processing mode N with water regulation function of the high quality of rice and its physiological and biochemical mechanisms,for the realization of the crop straw and sewage sludge resource utilization to provide theoretical guidance and practical basis.The main results were as follows:1.The way of straw returned the influence of water and N management on rice yieldThe effects of straw returning and water and N management on dry matter accumulation,leaf area index（LAI）and yield of rice were significant or extremely significant,and the interaction effect was significant,and the population quality index was significantly or very significantly positively correlated with yield（0.49*⁰.95**）.The regulation of straw composting and returning to field on rice population quality index was significantly higher than that of straw direct returning to field.The high efficiency LAI increased by 4.71%⁶.50%at full heading stage,and the dry matter of population increased by 9.22%¹3.3%.The effective panicles and grains per panicle increased by5.9%⁹.8%and 1.5%⁵.2%respectively,which increased the yield by 9.5%¹3.4%.Controlled alternative irrigation can ensure sufficient panicles,increase dry matter accumulation,slow down the decay rate of leaf area from jointing to full heading stage,accelerate the population growth rate during fruit setting stage,and benefit the increase of grain number per panicle and yield;and with the increase of N application,tillering number,dry matter accumulation,effective leaf area efficiency and high efficient leaf area efficiency all show the trend of first increase and then decrease.From the effect of three factors,when the amount of N applied and controlled alternate irrigation was 150 kg/hm²,the LAI（4.80⁵.32）and dry matter accumulation（6.94-7.36 t/hm²）in the period of full harvest could be effectively increased,and the effective panicle（181.6-220.9*10⁴/hm²）and the number of grains per panicle（180²00 grains）could be significantly increased,thus the yield could reach 10328.1¹2464.1 kg/hm².It can provide theoretical guidance and practical basis for efficient utilization of crop straw and water and fertilizer resources.2.Effects of Straw Returning and Water and N Management on Rice QualityThe effects of straw returning treatment,irrigation method and N application rate on rice roughness,head rice rate and chalky grain rate were significant or extremely significant.Compared with submerged irrigation,controlled alternative irrigation has higher water production efficiency and can significantly improve rice processing,appearance and taste quality,and its effect on rice chalkiness and chalky grain rate is more obvious,showing that W2 is better than W1;the effect of irrigation methods on rice quality is significantly higher than that of straw returning.The effect of N Application on milled rice rate,chalkiness,chalky grain rate and cooking taste value was obvious.Generally speaking,straw composting and returning to the field can obviously improve rice roughness and milled rice rate,but it has a certain negative effect on chalky,chalky grain rate and taste quality,which reduces rice quality as a whole.Controlled alternative irrigation can effectively improve rice quality.With the increase of N application,rice taste quality gradually decreases as a whole.From the effect of the three factors,the rice quality could be improved when the straw was returned to the field directly and Controlled Alternate Irrigation and N application were 75¹50 kg/hm².3.Effects of Straw Returning and Water and N Management on N UtilizationThe effects of straw returning and water and N management on N accumulation,N transport and N use efficiency of rice in the main growth stages were significant or extremely significant,and the interaction effect was significant.The regulation of straw composting and returning to field on rice N utilization was significantly higher than that of straw returning to field directly.The accumulation of N increased by 14.5%²0.5%at maturity stage.Controlled alternative irrigation can ensure that plants absorb nutrients adequately compared with submerged irrigation,and then increase the total N accumulation of plants at all growth stages;and with the increase of N fertilizer use,the N accumulation of plants increases first and then decreases.From the effect of the three factors,when the amount of N applied and controlled alternate irrigation was 150 kg/hm²,the accumulation of N and the utilization efficiency of N fertilizer could be effectively improved under the treatment of straw composting and returning to the field,which laid a theoretical foundation for the best treatment of saving water and reducing N,and for the synchronous improvement of rice yield and utilization of N fertilizer.4.Effects of Straw Returning and Water and N Management on Physical and Chemical Properties of Paddy SoilStraw returning and water and N management have significant regulatory effects on soil total N,nitrate N,ammonia N organic matter,urease,available phosphorus and available potassium,and the interaction effect is significant.The regulation of straw composting on paddy soil was significantly higher than straw direct returning,and the effects of straw returning on soil total N,organic matter,urease,available phosphorus and available potassium were significantly higher than those of irrigation.Controlled alternative irrigation can improve the decomposition efficiency of straw,and then improve the nutrients of paddy fields.The effect of straw returning on soil physical and chemical properties was significantly higher than that of irrigation.With the increase of N application rate,the effects on soil total N,nitrate N,ammonia N,organic matter and urease were significant.The indexes increased first and then decreased with the increase and decrease of N application rate at heading and maturity stages.From the effect of three factors,when the amount of N applied and controlled alternative irrigation was 150 kg/hm²,the soil nutrients could be effectively improved and the physical and chemical properties of soil could be improved,which could lay a theoretical foundation for the efficient utilization of crop straw and water and fertilizer resources and the improvement of soil physical and chemical properties.