Effects of plant density and nitrogen rate on cotton yield and nitrogen use in cotton stubble retaining fields  

作　　者：WANG Shi-hong MAO Li-li SHI Jia-liang NIE Jun-jun SONG Xian-liang SUN Xue-zhen 

机构地区：[1]Agronomy College,Shandong Agricultural University,Tai’an 271018,P.R.China [2]Liaocheng Academy of Agricultural Sciences,Liaocheng 252000,P.R.China [3]Dezhou Academy of Agricultural Sciences,Dezhou 253000,P.R.China

出　　处：《Journal of Integrative Agriculture》2021年第8期2090-2099,共10页农业科学学报（英文版）

基　　金：The study was supported by the National Natural Science Foundation of China(31601253);the Natural Science Foundation of Shandong Province,China(ZR2016CQ20);the China Postdoctoral Science Foundation(2017M610438);the Modern Agro-industry Technology Research System of Shandong Province,China(SDAIT-03-03/05).

摘　　要：Increasing nitrogen(N)rate could accelerate the decomposition of crop residues,and then improve crop yield by increasing N availability of soil and N uptake of crops.However,it is not clear whether N rate and plant density should be modified after a long period of cotton stubble return with high N rate.This study seeks to assess the effects of N rate and plant density on cotton yield,N use efficiency,leaf senescence,soil inorganic N,and apparent N balance in cotton stubble return fields in Liaocheng,China,in 2016 and 2017.Three plant densities 5.25(D_(5.25)),6.75(D_(6.75))and 8.25(D_(8.25))plants m^(-2) and five N rates 0(N_(0)),105(N_(105)),210(N_(210)),315(N315),and 420(N420)kg ha^(-1) were investigated.Compared to the combination used by local farmers(D_(5.25)N_(315)),a 33.3%N reduction and a 28.6%increase in plant density(D_(6.75)N_(210))can maintain high cotton yield,while a 66.7%N reduction at 6.75 plants m^(-2)(D_(6.75)N_(105))can only achieve high yield in the first year.Biological yield increased with the increase of N rate and plant density,and the highest yield was obtained under 420 kg N ha^(-1) at 8.25 plants m^(-2)(D_(8.25)N_(420))across the two years under investigation.Compared to D5.25N315,N agronomic efficiency(NAE)and N recovery efficiency(NRE)in D_(6.75)N_(210) increased by 30.2 and 54.1%,respectively,and NAE and NRE in D6.75N105 increased by 104.8 and 88.1%,respectively.Soil inorganic N decreased sharply under 105 kg N ha^(-1),but no change was found under 210 kg N ha^(-1) at 6.75 plants m^(-2).N deficit occurred under 105 kg N ha^(-1),but it did not occurr under 210 kg N ha^(-1) at 6.75 plants m^(-2).Net photosynthetic rate and N concentration of leaves under N rate ranging from 210 to 420 kg ha^(-1) were higher than those under N rate of 0 or 105 kg N ha^(-1) at all three densities.The findings suggest that D6.75N210 is a superior combination in cotton stubble retaining fields in the Yellow River Valley and other areas with similar ecologies.

关 键 词：leaf senescence N application rate N use efficiency seed cotton yield soil apparent N surplus 

分 类 号：S562[农业科学—作物学]