Changes in the soil microbial community structure with latitude in eastern China, based on phospholipid fatty acid analysis

Phospholipid fatty acid (PLFA) profiles were measured in soils from 14 sites in eastern China representing typical geographic zones of varying latitude from north (47.4°N) to south (21.4°N). Amounts of soil microbial biomass, measured as total amounts of PLFAs, showed no regular trend with latitude, but were positively correlated with soil organic carbon content, the concentration of humic acid and amorphous iron oxide. Soil microbial community structure showed some biogeographical distribution trends and was separated into three groups in a cluster analysis and principal coordinate analysis of log transformed PLFA concentrations (mol%). Soils in the first group came from northern China with medium mean annual temperature (1.2–15.7 °C) and rainfall (550–1021 mm). Soils in the second group originated from southern China with a relatively higher mean annual temperature (15.7–21.2 °C) and rainfall (1021–1690 mm). Soils clustered in the third group originated from the most southerly region. The northern soils contained relatively more bacteria and Gram-negative PLFAs, while the southern soils had more fungi and pressure indexed PLFAs. These differences in soil microbial community structure were largely explained by soil pH, while other site and soil characteristics were less important.