Soil bacterial community diversity under different degrees of saline-alkaline in the Hetao Area of Inner Mongolia

Denaturing gradient gel electrophoresis (DGGE) based on analyzing V3~V6 variable regions of bacterial 16S rDNA, were used to examine the microbial community structure and diversity in different saline-alkaline soils (saline soil, strongly salinized soil and slight salinized soil) and soil depths (0~20 cm, 20~30 cm) in the Hetao Area of Inner Mongolia. Their physical and chemical properties were measured, respectively. Experimental results showed that bacterial community structure and diversity decreased with the different saline-alkaline soil (slight salinized soil> strongly salinized soil> saline soil) and declined with soil depths (0~20 cm> 20~30 cm). Shannon-Wiener index of bacterial community in slight salinized soil was the highest value (3.36), while it was only 3.05 and 2.49 in strongly salinized soil and saline soil. The cluster analysis of DGGE bands showed that the bacterial community structure and diversity formed two distinct clusters 0~20 cm and 20~30 cm. Shannon-Wiener index of bacterial community in 0~20 cm layer (saline soil 3.04, strongly salinized soil 3.29, slight salinized soil 3.36) were higher than 20~30 cm layer (saline soil2.49, strongly salinized soil 3.05, slight salinized soil 3.14). Analyses of Pearson correlation and CCA revealed that variations of bacterial community structure were mainly affected by contents of w (EC), pH, w (SOC), w (TP). The soil bacteria diversification index has a negative correlation with the w (EC) (r= -0.542, P © 2016, Chinese Society for Environmental Sciences. All right reserved.