Carbon Source Utilization of Microbes in Saline Soil of Three Vegetation Types in Xinjiang, China: Carbon Source Utilization of Microbes in Saline Soil of Three Vegetation Types in Xinjiang, China

Abstract

Soil microbial process plays an important role in the conversion of soil organic carbon into inorganic carbon,which is significant for the global carbon cycle.The aim of this study was to investigate the microbial functional diversity of carbon source utilization in three vegetation types under natural conditions along Sangong River basin in Fukang,Xinjiang,China.The three typical vegetation types were dominated by Haloxylon ammodendron,Reaumuria soongorica,and Cleistogenes chinensis,respectively.The soil type is saline soil in this area with varied alkalinity.BIOLOG method was used to determine capability of soil microorganisms in utilizing 31 types of single carbon source.Correlation between soil physicochemical property(pH,water content,total soluble salt) and AWCD(the average well color development),Shannon diversity index,richness value were analyzed.Microbial AWCD in H.ammodendron plot was significantly higher than that of the other two plots(P0.01).pH value(pearson correlation=0.798,P0.01) and total carbon content(pearson correlation=0.655,P0.05) of the soil were closely associated with the value of AWCD,while the effect of water content and total soluble salt was not significant.In this study,the H.ammodendron vegetation had the highest soil total carbon content as well as the highest soil alkalinity while the ability of utilizing carbon source of its soil microbial community was higher than the other two vegetation types.The analysis of normalised optical density(OD) data with PCA(principal component analysis) showed that eleven carbon sources(five types of carbohydrates,two types of amino acid,four types of carboxylic acids) were well used by the soil microbes of H.ammodendron vegetation,six carbon sources(one of the carbohydrates,three of amino acid,two of carboxylic acids) were better metabolized in R.soongorica community.In addition,the soil microbes in C.chinensis vegetation only effectively utilized five out of thirty-one single carbon sources.It was assumed that higher total carbon content and alkalinity would result in higher utilization in the soil microbial community.This result will be benefit for the management of desertification and will contribute to the understanding of the underground carbon process in the saline soil in arid area and the research works on carbon cycle.