Effects of biological soil crust on slope soil carbon and nitrogen under erosion conditions
MENG Jie, BO Chong-Feng, LI Chi, ZHANG Xin-Chang, SUN Tie-Feng, ZHANG Xiao-Jun
1. College of Resources and Environment, Northwest A & F University, 712100,Yangling, Shaanxi；2. Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, 712100,Yangling, Shaanxi；3. Soil and Water Conservation in China Press, 450003, Zhengzhou: China
Abstract：In order to reveal the effects of biological soil crust (BSC) on the distribution of soil carbon and nitrogen on slope under erosion conditions, by experimenting on field plots and in laboratory, this study investigated the distribution pattern of soil organic matter, total nitrogen and nitrate nitrogen contents with BSC treatment and without crust group. The results indicated that: biological soil crust played significant role in soil carbon and nitrogen accumulation. In the same position on slope, soil organic matter, total nitrogen and nitrate nitrogen contents of BSC treatment in soil profile of 0-20cm depth were higher than those without crust group. On the whole, the accumulation effect of BSC on soil carbon and nitrogen was mainly concentrated in the 0-10cm soil layer. Compared with no crust, the average storages of soil organic matter, total nitrogen, nitrate nitrogen and ammonium nitrogen were increased by 44.7%, 18.2%, 39.2% and 4.33%, respectively. BSC could significantly increase soil nitrate nitrogen content of 0-2cm and 2-5cm soil layers (P<0.05), which may be explained by that BSC could control nitrate nitrogen loss by effectively reducing soil erosion and also release some amount of nitrate nitrogen during the studying period. Due to the loss characteristics of soil ammonium nitrogen were different from nitrate nitrogen, the effect of BSC on soil ammonium nitrogen was not obvious. Correlation analysis showed that there were highly significant or significant positive correlations between soil organic matter and total nitrogen, nitrate nitrogen and ammonium nitrogen (respectively P<0.01, P<0.05). Therefore, it can be concluded that the presence of biological soil crust would have favorable effects on soil carbon and nitrogen accumulation under erosion conditions, which indicate BSC could be of great positive significance to restoration and reconstruction of degraded ecosystem in research area.
2011, Vol. 9 
