Effects of Different Fertilizers on Functional Diversities of Microbial Flora in Rhizospheric Soil of Monoculture Tobacco

Abstract

Tobacco is an intolerant continuous cropping crop.Continuous cropping obstacle restricts sustainable development of tobacco production,which is one of the most important problems in agricultural production.In this study,tobacco consecutively planting for twelve years in the same and the rhizospheric soil was sampled to investigate the changes in the functional diversities of microbial flora after different fertilizer treatments.The results showed that the autotoxic allelopathic potential was maximum for the monoculture soil treated with traditional compound fertilizer,and minimum for the soil treated with farmyard manure.BIOLOG analysis showed that the traditional compound fertilizer was conducive to the growth of the microbial flora feeding on amino acids and amine as carbon sources.The commercial organic fertilizer was favorable to the growth of the microbial flora using carboxylic acids as a carbon source,and farmyard manure was good for the growth of the microbial flora feeding on carbo-hydrate,fatty acids,and phenolic acids as carbon sources.Principal component analysis indicated that the first two components related to carbon sources accounted for 74.37% and 25.63% of the data variation,respectively.The carbon source of carbohydrate,fatty acids,and phenolic acids made a mainly contribution to the separation of two principal components.Correlation analysis indicated that the autotoxic allelopathic potential of tobacco rhizospheric soil was positively correlated with the average well color development(AWCD) value of microbial flora feeding on carbohydrate and phenolic acids as carbon sources,and negatively cor-related with that of the microbial flora using the carbon source of fatty acids.In addition,for the growth of microbial flora in monoculture soil,farmyard manure was the best,commercial organic fertilizer showed the medium effect,and traditional com-pound fertilizer had the worst effect.