RESPONSE OF MICROBIAL BIOMASS CARBON, COMMUNITY AND ACTIVITY TO FREEZE-THAW CYCLES OF SALINE-ALKALI SOIL

摘要

The freeze-thaw cycles (FTCs) are recognized as important ecological processes in soil science and microbiology. The aim of this study was to increasing knowledges on how FTCs alter the saline-alkali soil microbial biomass carbon, community and activities. In the laboratory investigation, the quantities of microbial community and activities during freeze-thaw cycles (FTCs) periods were studied. The FTCs soil was paddy soils, collected from Northeast of China. The microbial biomass carbon, microbial communities and activities were detected under different FTCs treatments. The results showed that the soil microbial biomass carbon decreased with increasing FTCs times. The numbers of bacteria, fungi and actinomyceto had changed significantly. The fungi/bacteria ratios were different under two temperature strengths. At -5 °C treatment, the ratio was higher than the control, while it was lower at -20 °C. The dominance of saline-alkali soil was fungal community. The inversase (INV) activities had the same changing tendency under two soil temperatures. In contrast, the polyphenol oxidase (PPO) activities increased firstly following reduction. However, the freeze-thaw cycle had a little influence of peroxidase (POD) activities on saline-alkali soil.