Effects of fertilization on bacterial community structure and function in a black soil of Dehui region estimated by Biolog and PCR-DGGE methods
Biolog和PCR-DGGE技术解析施肥对德惠黑土细菌群落结构和功能的影响

Black soils(Mollisols) in China are primarily distributed in the northeast region,which is one of the three largest Mollisol areas in the world.Although original black soils are commonly thought to be fertile and productive,some of the cultivated black soils have been degraded after more than 100 years of cultivation.Many researchers have reported the influences of organic and inorganic fertilizers application on crop yield,and changes in soil physical and chemical characteristics in the black soils,but less attention has been paid on soil microbial communities.In this paper,we used Biolog and PCR-DGGE methods to examine the influences of the fertilization on structure and function of bacterial community in a black soil of Dehui region,Jilin Province.Biolog examination showed that substrate richness and catabolic diversities of soil bacterial community were the highest in the treatment of farm yard manure.However,the opposite was observed in the treatment of chemical fertilizers;the metabolic ability of bacterial community was decreased after using chemical fertilizers.DGGE fingerprint showed that the distribution patterns of most bands of 16S rDNA were similar among all treatments,indicated that microbe with those bands were stable,not influenced by fertilization treatment.In general,chemical fertilizer decreased the diversity of soil bacterial community.The PCA plots of Biolog and DGGE revealed that the structure and function of bacterial community were similar in the non-fertilized control and the treatment of farm yard manure alone,which inferred that the application farm yard manure had increased the quantity of soil microbes but had less effect on the bacterial community structure.The catabolic function was similar but composition structure differed between the treatments of chemical fertilizer alone and comined application of farm yard manure and chemical fertilizer.These results suggest the use of chemical fertilizer mainly declined the catabolic activity of the fast growth bacteria or eutrophic bacteria.