Effect of straw-returning amount and manner on the nutrient uptake,yield and quality of flue-cured tobacco

Effect of straw-returning amount and manner on the nutrient uptake,yield and quality of flue-cured tobacco were studied in field condition.The results showed:(1) Straw-returning treatment increased shoot biomass apparently,the decomposed straw and direct straw-returning treatments were better than straw-covering treatment.The effeciency of straw-returning was positively correlated to the straw-returning,but the effeciency of direct straw-returning treatment descended when the amounts excessed 5 250 kg·hm-2.(2)Sstraw-returning treatment improved the accumulation of N,P,K,Ca,Mg,Zn,Mn in plant,the decomposed straw and direct straw-returning treatments were superior to straw-covering treatment.The accumulation of N,P,K was positively correlated to straw-returning amount generally,but the correlation between the accumulation of Ca,Mg, Zn,Mn and the amounts was unapparent.(3)The straw-returning treatment decreased the amounts of reducing sugar,TN and RS/Nie in middle leaves,meanwhile,increased the amounts of Nie and TN in top and middle leaves,the effect on top leaves was most obvious by decomposed straw-returning way,the relationship between effect and amounts showed positive correlation,the effect on top leaves was most obvious by direct straw-returning way,between effect and amounts also showed positive correlation.(4)The treatments improved the economic characteristics of cured tobacco,but the effeciency treatments of decomposed straw-returning and direct straw-returning treatments decreased when over-retruning the straw amounts.