Effects Of Returning Straws-to-field On Yield And Quality Of Flue-cured Tobacco, Soil Physical And Chemical Characteristics

In Hunan Liu yang, with the field trials, the ways and amounts of returning-straws-to-field on the nutrient uptake and quality of fiue-cured tobacco werestudied.The results showed:1) Returning-straws-to-field significantly increased tobacco biomass,returning-decomposed-straws-to-field and returning-straws-to-field directly arebetter than straw mulching.The effects of the treatments are positively correlatedwith the amount of returning-straws-to-field, but when the gross amount over5250kg,the results are worse;2)Promoted the accumulation of N,K,Ca,Mg,Zn,Mn in plant, but the effectP accumulation was unapparent, increased the utilization efficiency of N,P,K,theeffect under decomposed straw way was most obvious.3)Decreased the amounts of reducing sugar, TN and RS/Nie in middle leaf,meanwhile, increased the amounts of Nie and TN in superior and middle leaf, theeffect of superior leaf was most obvious under returning-decomposed-straws-to-field way, the relationship between effect and amounts showed positivecorrelation, the effect of middle leaf was most obvious under returning-straws-to-field directly way, between effect and amounts also showed positivecorrelation.4) Increased the yield, production value, proportion of high and middle grad,average value of flue-cured, the relationship between effect and amounts showed positive correlation, but out fixed extent, the effect decreased underreturning-decomposed-straws-to-field way.5) Increased physical sand particles slightly. Increased Coarse sand particlesand silt content, and fine sand and fine clay content declined. In three returning-to-field ways, the effects of soil particle composition are not obvious;6) Increased the quantity of soil organic matter and soil humus content andthe nitrogen source, a high dosage of returning-decomposed-straws-to-field andreturning-straws-to-field directly are better. Returning-straws-to-field directly ofthree ways increase the content of the soil humic acid and humic larger;7) Increase the effectiveness of Fe and content of exchangeable Mg slightly,but declined exchangeable Ca content, returning-straws-to-field directly increasedthe activity of Mn in soil, but the effect of Zn activity is not very clear.