追施氮肥对不同测定位置棉花冠层结构和产量的影响OA北大核心CSTPCD

[Objective]This research aims to investigate the impact of different nitrogen(N)fertilizer rates on cotton under the machine picked with(66+10)cm row spacing,so as to provide scientific basis for improving the high-yield cultivation technology of cotton.[Methods]N top-dressing experiments was carried out in Korla of Xinjiang during 2021 and 2022.A field experiment was conducted using Ba 43541 as the test material,and four pure N application levels were set:0,112.5,225.0,and 337.5 kg·hm-2.Canopy structure characteristics,yield traits,and N use efficiency of cotton in middle position of the wide line(MW),middle position of the narrow line(MN),adjacent to plant(AP)and intermediate position of the adjacent two membranes(MC)were compared under different treatments.[Results]Under different treatments,with the advancement of growth process,leaf area index(LAI)of cotton at the four test sites increased first and then decreased,while photosynthetically active radiation(PAR)decreased first and then increased,but mean leaf angle(MLA)and gap fraction transmission coefficient(GFTC)showed different change trends.During the full budding stage,the LAI was lower,while MLA,PAR,and GFTC were higher in MC.The differences of LAI,PAR,and GFTC among the four test sites gradually decreased from the flowering and boll setting stage to the boll opening stage.During the full boll setting stage and boll opening stage,MLA were higher in MN and AP.Applying N 112.5 kg·hm-2(N1)obtained appropriate LAI,MLA,PAR,and GFTC during the full boll setting stage,the boll number of per unit area increased.In 2021 and 2022,compared with the other three treatments,seed cotton yield of N1 increased by 1.38％-16.50％and 1.66％-11.57％,and lint yield increased by 1.57％-16.37％and 0.59％-12.40％,respectively;partial productivity and agronomic utilization of N were also increased.In terms of cotton LAI and PAR,there were extremely significant positive correlation among the four test sites.Overall,the best positive correlation of cotton canopy structure index was found among AP and MW,AP and MN.[Conclusion]Under the same N application rate,the change trends of LAI and PAR at four test sites were consistent,while the change trends of MLA and GFTC were inconsistent.The application of 112.5 kg hm-2 N could promote the high yield of Ba 43541,and improve the N use efficiency of cotton.