SOIL CARBON AND NITROGEN DYNAMICS INDUCED BY TISSUE-LITTER DECOMPOSITION OF COPPER MINE TAILINGS FROM THE GRAMINEAE AND CRYPTOGRAM COMMUNITIES, CHINA

摘要

A field survey was conducted to investigate the effects of the plant communities' succession on soil carbon and nitrogen dynamics in copper mine tailings from Tongling City, China. The soil and tissue litter of gramineae (Imperata cylindrica (Linn.) Beauv. and Zoysia sinica Hance) and cryptogam (Hippochaete ramosissmium and algalmoss crusts) were collected. The differences and relationships of carbon concentration, nitrogen concentration, carbon-13 isotope ratio, and nitrogen-15 isotope ratio were determined between litter and soil. The results showed that the correlation of carbon concentration between the litter and soil was significant in gramineae, whereas no significant correlation was observed in cryptogam. The carbon-13 isotope and nitrogen- 15 isotope ratios of litter were lower than those of soil. The soil carbon-13 isotope and nitrogen-15 isotope ratios in all areas were lower than those in the absence of plants. The effects of I. cylindrica and algal-moss on soil~(13)C enrichment were significant and the microbial biomass carbon, water concentration, and pH also affected the soil carbon- 13 isotope ratio. In contrast, significant correlation was observed only between microbial biomass nitrogen and soil nitrogen-15 isotope ratio, and the other factors had no obvious effects on soil nitrogen-15 isotope ratio in the tailings.