The efficacy of chemical topping in field-grown cotton is mediated by drip irrigation amount in irrigated agricultural area  

作　　者：TIAN Yu LIAO Baopeng HAN Huanyong WANG Fangyong DU Mingwei TIAN Xiaoli LI Zhaohu 

机构地区：[1]Xinjiang Academy of Agricultural and Reclamation Science,Shihezi 832003,Xinjiang,China [2]College of Agronamy/Crop Chemical Control Research Center,China Agricultural University,Beijing 100193,China [3]Callege of Agron-omy,Shihezi University,Shihezi 832000,Xinjiang,China.

出　　处：《Journal of Cotton Research》2022年第2期173-184,共12页棉花研究（英文）

基　　金：financially supported by the Research Fund for the National Natural Science Foundation of China (31760369);Xinjiang Corps Science and Technology Innovation Talent Program (2020CB014);Major projects of the eighth Division (2020ZD01)

摘　　要：Background:Cotton production in China is challenged by high labor input including manual topping(MT).Recently,to replace MT in the Xinjiang cotton region of China,mepiquat chloride(MC)was applied once more than the traditional multiple-application;this was designated as chemical topping(CT),but it is unclear whether the amount of irrigation needs to be adjusted to accommodate CT.Results:The main plots were assigned to three drip irrigation amounts[300(I_(1))480(I_(2)), and 660(I_(3))mm],and the subplots were assigned to the CT treatments[450(MC)750(MC_(2)),and 1050(MC_(3))mL·hm^(-2)25%MC]with MT as a control that was performed after early bloom.The optimum drip irrigation amount for CT was explored based on leaf photosynthesis,chlorophyll fluorescence,biomass accumulation,and yield.There were significant influe nces of drip irrigation,topping treatme nts and their interaction on chlorophyll fluorescence characteristics,gas exchange parameters and biomass accumulation characteristics as well as yield.The combination of I_(2) and MC_(2)(I_(2)MC_(2))performed best.Compared with I_(2)MC_(2)the net photosynthetic rate(Pn),stomatai conductance(Gs),transpiration rate(Tr),and photochemical quenching coefficient(qP)of I_(2)MC_(2)significantly increased by 4.0%~7.2%,6.8%〜17.1%,5.2%~17.6%,and 4.8%~9.6%,respectively,from the peak flowering to boll opening stages.Moreover,I_(2)MC_(2) showed fast reproductive organ biomass accumulation and the highest seed cotton yield;the latter was 6.6%~12.8%higher than that of I_(2)MT.Further analysis revealed that a 25%MC emulsion in water(MCEW)application resulted in yield improvement by increasing Pn,φPSⅡ,and qP to promote biomass accumulation and transport to reproductive organs.Conclusion:The results showed that the 480 mm drip irrigation combined with 750 mL·hm^(-2)MC increased the rate of dry matter accumulation in reproductive organs by increasing Pn,φPSⅡ and qP to improve photosynthetic performance,thus achieving higher yield.

关 键 词：COTTON Irrigation amount Chemical topping PHOTOSYNTHESIS Biomass accumulation 

分 类 号：F42[经济管理—产业经济]