Increasing the appropriate seedling density for higher yield in dry direct-seeded rice sown by a multifunctional seeder after wheatstraw return  

作　　者：TIAN Jin-yu LI Shao-ping CHENG Shuang LIU Qiu-yuan ZHOU Lei TAO Yu XING Zhi-peng HU Ya-jie GUO Bao-wei WEI Hai-yan ZHANG Hong-cheng 

机构地区：[1]Jiangsu Key Laboratory of Crop Cultivation and Physiology/Innovation Center of Rice Cultivation Technology in Yangtze Valley,Ministry of Agriculture and Rural Affairs/Co-Innovation Center for Modern Production Technology of Grain Crops,Yangzhou University,Yangzhou 225009,P.R.China [2]Agricultural College,Xinyang Agriculture and Forestry University,Xinyang 464000,P.R.China

出　　处：《Journal of Integrative Agriculture》2023年第2期400-416,共17页农业科学学报（英文版）

基　　金：the Jiangsu Agriculture Science and Technology Innovation Fund, China (CX(20)1012);the Jiangsu Demonstration Project of Modern Agricultural Machinery Equipment and Technology, China (NJ2020-58);the Jiangsu Technical System of Rice Industry, China (JATS[2020]432);the National Key Research and Development Program of China (2016YFD0300503);the earmarked fund for China Agriculture Research System (CARS-01-27);the Yangzhou University Scientific Research and Innovation Program, China (XKYCX20_022)。

摘　　要：Dry direct-seeded rice(DDR) sown using a multifunctional seeder that performs synchronous rotary tillage and sowing has received increased attention because it is highly efficient,relatively cheap,and environmentally friendly.However,this method of rice production may produce lower yields in a rice–wheat rotation system because of its poor seedling establishment.To address this problem,we performed field experiments to determine the rice yield at five seedling density levels(B1,B2,B3,B4,and B5=100,190,280,370,and 460 seedlings m-2,respectively) and clarify the physiological basis of yield formation.We selected a representative high-quality rice variety and a multifunctional seeder that used in a typical rice–wheat rotation area in 2016 and 2018.The proportion of main stem panicle increased with increasing seedling density.There was a parabolic relationship between yield and seedling density,and the maximum yield(9.34-9.47 t ha-1) was obtained under B3.The maximum yield was associated with a higher total spikelet number m-2 and greater biomass accumulation from heading to maturity.The higher total spikelet number m-2 under B3 was attributed to an increase in panicle number m-2 compared with B1 and B2.Although the panicle numbers also increased under B4 and B5,these increases were insufficient to compensate for the reduced spikelet numbers per panicle.Lower biomass,smaller leaf area,and lower N uptake per plant from the stem elongation stage to the heading stage were partially responsible for the smaller panicle size at higher seedling density levels such as B5.The higher biomass accumulation under B3 was ascribed to the increases in the photosynthetic rate of the top three leaves m-2 of land,crop growth rate,net assimilation rate,and leaf area index.Furthermore,the B3 rice population was marked by a higher grain–leaf ratio,as well as a lower export ratio and transport ratio of biomass per stem-sheath.A quadratic function predicted that 260-290 seedlings m-2 is the optimum seedling density for achieving maxim

关 键 词：seedling density dry direct-seeded rice sown by a multifunctional seeder rice–wheat rotation system yield biomass photosynthetic capacity 

分 类 号：S511[农业科学—作物学]