Long-term straw return with appropriate nitrogen(N)fertilization increases seedcotton yield and fiber quality,and the root system plays an important role in cotton production.However,under straw return and N fertiliza...Long-term straw return with appropriate nitrogen(N)fertilization increases seedcotton yield and fiber quality,and the root system plays an important role in cotton production.However,under straw return and N fertilization,the relationship between the cotton boll-loading capacity of the root system and seedcotton yield remains unclear.In this study,a ten years of long-term field experiment was conducted in a wheat-cotton rotation system.The effects of straw treatments(straw return and straw removal)and N rates(N0,N75,N150 and N300 representing 0,75,150 and 300 kg N ha^(-1),respectively)on cotton root activity,boll-loading capacity of the root system and their relationship to seedcotton yield from 2019 to 2022 were quantified.The results showed that straw return with an appropriate N fertilization of N150 increased root biomass,the rate and components of root-bleeding sap,as well as boll-loading capacity of the root system and seedcotton yield,but decreased the ratio of root to shoot biomass.Furthermore,the root-bleeding sap rate reached the maximum at 30 d post anthesis(DPA)during the peak boll setting stage.However,the contents of nitrate-N,free amino acids and soluble sugar in root-bleeding sap decreased from 10 DPA.Notably,in 2021 and at 30 DPA,the highest contents of nitrate-N(4.8μg mL^(-1))and free amino acids(8.3μg mL^(-1)),as well as soluble sugar(3.4μg mL^(-1))were observed at N150 under straw return.The increase in seedcotton yield is positively correlated to the soluble sugar content.Straw return significantly increased the boll-loading capacity of the root system,which first increased but then decreased with the increase in N fertilization.Under straw return with N150,the maximum seecotton yield(3455-4544 kg ha^(-1))was recorded,and the largest boll loading(49-54 boll 100 g^(-1))and boll capacity(242-292 g 100 g^(-1))of root system at the boll opening stage were observed.Therefore,straw return with appropriate N fertilization improved root activity and the boll-loading capacity of the root system,thereby increasing seedcotton yield.This study provides new insights into improving seedcotton yield from the perspective of coordinating cotton growth.展开更多
基金supported by the Jiangsu Agricultural Science and Technology Innovation Fund(CX(22)2015)the Fundamental Research Funds for the Central Universities(XUEKEN2022008)+1 种基金the Innovation Center for Modern Crop Production Cosponsored by Province and Ministry(CIC-MCP)the Cotton Industry Technology Research System of Shandong Province(SDAIT-03).
文摘Long-term straw return with appropriate nitrogen(N)fertilization increases seedcotton yield and fiber quality,and the root system plays an important role in cotton production.However,under straw return and N fertilization,the relationship between the cotton boll-loading capacity of the root system and seedcotton yield remains unclear.In this study,a ten years of long-term field experiment was conducted in a wheat-cotton rotation system.The effects of straw treatments(straw return and straw removal)and N rates(N0,N75,N150 and N300 representing 0,75,150 and 300 kg N ha^(-1),respectively)on cotton root activity,boll-loading capacity of the root system and their relationship to seedcotton yield from 2019 to 2022 were quantified.The results showed that straw return with an appropriate N fertilization of N150 increased root biomass,the rate and components of root-bleeding sap,as well as boll-loading capacity of the root system and seedcotton yield,but decreased the ratio of root to shoot biomass.Furthermore,the root-bleeding sap rate reached the maximum at 30 d post anthesis(DPA)during the peak boll setting stage.However,the contents of nitrate-N,free amino acids and soluble sugar in root-bleeding sap decreased from 10 DPA.Notably,in 2021 and at 30 DPA,the highest contents of nitrate-N(4.8μg mL^(-1))and free amino acids(8.3μg mL^(-1)),as well as soluble sugar(3.4μg mL^(-1))were observed at N150 under straw return.The increase in seedcotton yield is positively correlated to the soluble sugar content.Straw return significantly increased the boll-loading capacity of the root system,which first increased but then decreased with the increase in N fertilization.Under straw return with N150,the maximum seecotton yield(3455-4544 kg ha^(-1))was recorded,and the largest boll loading(49-54 boll 100 g^(-1))and boll capacity(242-292 g 100 g^(-1))of root system at the boll opening stage were observed.Therefore,straw return with appropriate N fertilization improved root activity and the boll-loading capacity of the root system,thereby increasing seedcotton yield.This study provides new insights into improving seedcotton yield from the perspective of coordinating cotton growth.
