Effects Of Tillage And Straw Return On Soil Physical And Chemical Properties And Flue-cured Tobacco Growth

Jiangxi Province belongs to the southeast tobacco growing area in China's tobacco growing zoning.The tobacco growing in this region mainly adopts the pattern of tobacco-rice rotation.Long-term single shallow tillage mode leads to shallow soil layer,thicker plow layer,and poor soil structure,which in turn affects the yield and quality of flue-cured tobacco.In order to solve the above problems of soil in Jiangxi tobacco area and improve the quality of tobacco leaves,this study designed a split-plot experiment to study the effects of different tillage methods and straw returning on soil physical and chemical properties and flue-cured tobacco production.The main plot was rotary tillage and deep tillage.The sub-plot was 0 kg/ha,3000 kg/ha,6000 kg/ha and 9000 kg/ha.The research results are as follows:1.Deep tillage and straw returning significantly improve the physical properties of the soil.Straw returning significantly reduced the soil bulk density of 5-10 cm and 20-25 cm soil layers,increased soil total porosity and capillary porosity.However,the effect of straw returning on the soil of40-45 cm soil layer is not significant.The effects of deep tillage on the three soil layers reached a significant level.Deep tillage significantly reduced soil bulk density of the three soil layers,increased soil total porosity and capillary pores.Compared with straw returning,deep tillage has a greater and deeper impact on soil physical properties.2.Straw returning increased soil nutrient availability,and the difference between tillage methods was not significant.The straw returning increased the content of available nutrients such as nitrogen,phosphorus and potassium in the soil.Among them,the highest increase of ammonium nitrogen in soil reached 72.99%,nitrate nitrogen reached 61.30%,and available phosphorus and available potassium reached 39.08% and 38.42%,respectively.Comparing the two methods of tillage and straw returning,the effect of straw returning on soil available nutrients was greater.3.During the whole growth period of flue-cured tobacco,the three soil enzyme activities showed a trend of increasing first and then decreasing.The effects of tillage and straw returning on soil enzyme activity were different.Straw returning increased the activity of soil enzymes.The highest increase in soil urease,invertase and acid phosphatase reached 49.57%,56.73%,and 13.64%,respectively.The activities of soil invertase and acid phosphatase were not significantly different between different straw returning fields(3000kg/ha,6000kg/ha,9000kg/ha).The soil urease activity increased with the increase of straw application.Under the same amount of straw returning,the effect of deep tillage on soil enzyme activity was small,which only significantly increased the activity of the later period soil urease and the previous acid phosphatase.Compared with the two methods of straw returning,the effect of straw returning on soil enzyme activity was greater.4.The effects of tillage and straw returning on the biomass and nutrient accumulation of flue-cured tobacco were different.Straw returning significantly increased the biomass of roots,stems and leaves of flue-cured tobacco,and also significantly increased the absorption of nitrogen,phosphorusand potassium in flue-cured tobacco..It appears that the biomass and nutrient accumulation of flue-cured tobacco roots and leaves are higher at 9000 kg/ha.Compared with rotary tillage treatment,deep tillage had little effect on the biomass of flue-cured tobacco roots,but significantly increased the biomass of stems and leaves,and also significantly increased the absorption of nitrogen,phosphorus and potassium.5.The effects of tillage and straw returning on the quality of flue-cured tobacco are different.Under the treatment of straw returning,the yield and output value of flue-cured tobacco have an increasing trend.At the same time,the returning of straw to the field also increased the content of potassium oxide and chlorine in tobacco leaves,reduced the ratio of sugar to alkali in roasted tobacco,and improved the sensory quality of flue-cured tobacco.Compared with rotary tillage,deep tillage significantly increased the yield and output value of flue-cured tobacco,increased the proportion of superior leaves,increased the sugar-base ratio and potassium oxide content of roasted tobacco,and reduced the chlorine content.Compared with the two methods of straw returning,the effect of tillage on the output value of flue-cured tobacco is greater than that of straw returning.