Effects Of Different Fertilizer Application Rates With Straw Incorporated On Yield,Quality And Element Absorption And Utilization Of Mechanical Transplanting Rice Nanjing 9108

With good taste and high quality rice Nanjing 9108 as materials,setting 20 treatments,referred to as "3420",with nitrogen(N),phosphorus(P),potassium(K)fertilizer 3 factors and 4 levels of application for each fertilizer in the straw-return conditions,using mechanical transplanting with carpet seedlings method,the experiment was conducted in Diaoyu town(33°05'N,119°58'E),Xinghua city,Jiangsu province during 2014 and 2015.The effects of different fertilizer application rates on yield,yield components,dry matter accumulation,quality and element absorption and utilization of mechanical transplanted rice Nanjing 9108 were comparatively studied to compare yield traits and quality traits in different fertilizer application rates,and identify the optimum fertilizer application of Nanjing 9108 for high yield and high quality.The results could provide theoretical and technical support for the rational fertilization of mechanical transplanted rice with good taste and high quality in the local area.The main results were as following:1.Significant differences in rice yield were observed among N treatments,and insignificant differences were among P and K treatments.The optimum fertilizer application for mechanical transplanted rice Nanjing 9108 with high yield were 270 kg/hm2 N,108 kg/hm2 P2O5,216 kg/hm2 K2O.2.Under the condition with same P and K application rates,the head rice rate and protein content showed increased trend,and gel consistency showed shortened trend,with the increase of N application rate.While amylose content was irregular with the increase of N application rate.The increase of P application rate did not induce significant difference in the traits of brown rice rate,milled rice rate,head rice rate,protein content,amylose content and gel consistency under the condition with same N and K application rates.The effects of K application rate on rice quality were significant.With the increase of K application rate,except that the gel consistency showed unclear trend,the milled rice rate,head rice rate and protein content were increased,and the amylose content was decreased,respectively.Moreover,the effect of N,P and K application rate on RVA profile characteristics of rice were N>K>P.In conclusion,the optimum NPK combination for mechanical transplanted rice Nanjing 9108 with high quality under the basis of high yield was N2P2K2.5 in the straw-return conditions,and the application rate for N,P and K were 270 kg/hm2 N,108 kg/hm2 P2O5,270 kg/hm2 K2O,respectively.3.Effect of N,P and K application rate on rice nitrogen uptake and utilization efficiency were N>K>P.The highest nitrogen accumulation was obtained by the treatment of N2P2K2.Relative lower ratio of nitrogen accumulation from transplanting date to stem elongation to total,and higher ratio of nitrogen accumulation from stem elongation to heading to total and from heading to maturity to total were important approaches for rice under N2P2K2 treatment to accumulate more nitrogen.In addition,higher N uptake rate during stem elongation to heading and heading to maturity phases greatly increased the nitrogen absorption and utilization of rice under N2P2K2 treatment.The effect of K application rate on nitrogen absorption and utilization was more obvious than P.With the increase of N application,The K absorption and utilization of rice was increased.Increasing the P fertilizer application also increased the K absorption utilization rate.With the increase of K application,rice under N2P2K3 showed higher K accumulation in transplanting to stem elongation phase,rice under N2P2K2.5 showed higher K accumulation in stem elongation to heading phase,and rice under N2P2K2 showed higher K accumulation in heading to maturity phase.The analysis of K absorption utilization rate showed that the K uptake per 100 kg grain and K harvest index were increased with the increase of K application rate,which reached the highest value under N2P2K3 treatment.However,the increase of K application rate decreased the K production efficiency and partial factor productivity of applied K.Therefore,the efficient utilization of K fertilizer should be attached importance to the cultivation technology research in order to realize the high-yield and high-K-utilization rice production under mechanical condition.This study demonstrated that the N2P2K2 was the optimum application mode for rice with good taste and high quality to produce more rice.The analysis of rice quality in different fertilizer application rates showed that the RVA profile of rice under N0P0K0,N0P2K2,and N2P2K2.5 were superior to other treatments,while the processing and nutrition quality of rice under N2P2K2.5 were better than NOPOKO and N0P2K2.Moreover,The rice yield under N2P2K2.5 was insignificantly smaller than N2P2K2,but the eating and cooking quality of rice under N2P2K2.5 were better than N2P2K2.Thus this study suggested that the N2P2K2.5,referred to 270 kg/hm2 N,108 kg/hm PaO5?270 kg/hm2 K2O,would be a better application mode to realize the high-yield and high-quality rice production under mechanical condition with good taste and high quality rice.