Effect Of Vermicompost Instead Of Part Fertilizer On Soil Characters And The Growth And Quality Of Flue-cured Tobacco

Flue-cured tobacco is an important economic crop in China.At present,a series of problems reduce the yield of tobacco and aggravate the soil quality deterioration because of continuous cropping and chemical fertilizer abuse.It is the way of replacing part of chemical fertilizers with organic fertilizers that is an effective way to improve the quality of soil and the yield of tobacco.So far,there are numerous studies of organic fertilizer alternative fertilizer on rice,corn and wheat,but it is poor on tobacco and the mechanism is still unclear.To explain the mechanism,this research focused on the effect that vermicompost instead of part fertilizer impact on soil characters as well as the growth and quality of flue-cured tobacco in Yunyan 99,which based on the continuous cropping planting field of Shangluo tobacco producing areas.The main conclusions were listed on the follow.1.The application of vermicompost,partial replacement of chemical fertilizer,can optimize the physicochemical and biological characteristics of soil in different degrees.Compared with the treatment of pure chemical fertilizer(T1),the soil bulk density decreased by an average of 2.38%,the organic matter increased by 36.13%,and the pH of soil was increased by 5.38%,which alleviated soil acidification to some extent.Furthermore,the soil urease,invertase,acid phosphatase and catalase increased by 25.31%,27.37%,23.38% and 15.07%,respectively.The number of bacteria,fungi and actinomycetes increased by 77.87%,39.99% and 56.99%,respectively.However,for soil available nutrient content,the treatment of vermicompost replaced 50% fertilizer(T3)and 70% fertilizer(T4)is slightly lower than T1,while the treatment of wormast replaced 30% fertilizer(T2)increased significantly comparing with T1.The alkali nitrogen,available phosphorus and available potassium was increased by 10.79%,9.83% and 6.34% under the treatment of T2,respectively.Generally,T4(vermicompost instead of 70% chemical fertilizer)had better effects on soil biological properties,but T2(vermicompost instead of 30% chemical fertilizer)had better effects on soil nutrient effect.The correlation analysis shows that there was a certain correlation between fertility factors.Principal component analysis indicated that the key indicators of the soil fertility difference include available potassium,available phosphorus,alkali hydrolysable nitrogen,fungi,actinomycetes,acid phosphatase,bacteria and organic matter.2.The vermicompost partly instead of fertilizer had different effects on the growth.Compared with pure chemical fertilizer treatment(T1),the root activity increased by 13.13% and 4.64% in T2 and T3 treatments,respectively,which indicated that the root could be benefited from vermicompost.In middle leaves,the activity of nitrate reductase increased by 13.67%~29.18%.Compared with T1,the highest level of the activity of amylase was occurred in T3 increased by 23.40%,then was T2 increased by 15.96%.Invertase activity of T2 was 7.12% higher than T1,which was the highest level among all treatments.The content of nitrogen and potassium achieved the highest content under the condition of T2 in the middle leaves,which increased by 1.74% and 12.5% compared with T1,respectively.But the phosphorus content was the highest in T4 and 22.73% higher than that in T1.3.Replacing some chemical fertilizer with earthworm manure had different effects on the quality and economic characters of flue-cured tobacco.Compared with the pure fertilizer treatment(T1),the replacement of vermicompost could effectively improve the coordination of the chemical composition in the upper and middle leaves as well as improve the sensory evaluation.In the middle leaves,the content of potassium and nitrogen increased by 5.22%~12.69% and 1.68%~5.03%,respectively.while the nicotine content decreased by 7.89%~12.90%.The ratio of sugar and alkali,potassium and chlorine,two sugar ratio and nitrogen base ratio all increased to the significant level.The content of potassium and potassium chlorine ratio increased significantly in the upper leaves and other indexes also improved.Compared with T1,the output of earthworm manure instead of part fertilizer increased by 6.40%~9.32%,and the proportion of superior tobacco increased by 13.37%~14.42%.The best comprehensive evaluation was earthworm manure instead of 30% fertilizer(T2),and then was replaced by 50% fertilizer(T3).4.Correlation analysis shows that it had closely pertinence between soil fertility and tobacco physiological indexes and a number of indicators reached extremely significant correlation.The correlation analysis also showed that the chemical index of flue-cured and physiological indexes were significantly correlated.Gray correlation analysis indicated that the effect of soil acid phosphatase,available potassium,organic matter and available phosphorus play the main role in the physiological activity of Flue-cured Tobacco.The physiological index including nitrogen,potassium,phosphorus and invertase had the greatest influence on tobacco chemical quality after baking.Soil fertility could be better improved by vermicompost to replace 30% chemical fertilizer(T2)after the above analysis,and which enhanced the quality of tobacco leaves.It appears to be applied in Shangluo,Shaanxi province and the same ecological area of tobacco.This study preliminarily clarified the key factors and mechanisms of soil fertility,tobacco quality and yield regulated by vermicompost instead of part chemical fertilizer,which provided an approach to improve the quality of soil,reduce chemical fertilizer and enhance the production quality of tobacco in continuous cropping areas.