Halophyte functional groups influence seasonal variations in rhizosphere microbial necromass and enzyme activities in an inland saline ecosystem.

In this study, we investigated the seasonal changes in enzyme activities and microbial necromass carbon (C) in the bulk and rhizosphere soils of different halophytes (shrubs, grasses, and forbs) in an inland saline ecosystem in China. We found that the soil enzyme activities and microbial necromass C were 45–646% higher in rhizosphere soils than bulk soils regardless of the season and halophyte functional group. The activities of soil enzymes and bacterial necromass C were highest for forbs (4.9–172.3 nmol g−1 h−1 and 473.2 mg kg−1, respectively), and grasses had the highest fungal necromass C (FN-C) and total necromass C/soil organic C (TN-C/SOC) ratio. Moreover, the soil enzyme activities were higher in the late season stage (4.0–154.0 nmol g−1 h−1) than the early (3.6–132.1 nmol g−1 h−1) and middle (3.8–128.9 nmol g−1 h−1) season stages. FN-C and TN-C/SOC ratio were significantly higher in the middle season than the early and late seasons. Redundancy analysis showed that the enzyme activities and microbial necromass C mainly depended on the soil physicochemical properties, season, and halophyte functional group. Our results indicate that microbial turnover was consistently faster in rhizosphere soil than bulk soil in an inland saline ecosystem, and forbs could be used as pioneer species to improve microbial turnover during the phytoremediation of saline ecosystems. [ABSTRACT FROM AUTHOR]