title: [Biological soil crust nitrogenase activity and its responses to hydro-thermic factors in different erosion regions on the Loess Plateau, China].
abstract: Based on field survey, the biological soil crusts at their stable development stage were collected from the water erosion region, water-wind erosion region, and wind erosion region on the Loess Plateau, aimed to study the effects of the variations of moisture and temperature on the crusts nitrogenase activity (NA). The NA of the crusts in the erosion regions decreased in the order of water erosion region (127.7 micromol x m(-2) x h(-1)) > water-wind erosion region (34.6 micromol x m(-2) x h(-1)) > wind erosion region (6.0 micromol x m(-2) x h(-1)), and the optimal temperature for the crust nitrogen fixation was 35 degrees C, 25 degrees C, and 15 degrees C, respectively. At the optimal temperature and 100% -40% field water-holding capacity, the NA of the crusts from the water erosion and water-wind erosion regions had no significant difference. The NA of the crusts from the wind erosion region was more sensitive to the variation of moisture, showing a dramatic decline when the moisture decreased to 80% field water-holding capacity, and totally lost when the moisture decreased to 20% field water-holding capacity. The differences in the NA of the crusts from the three erosion regions and the responses of the NA to the variations of moisture and temperature were likely associated with the climate, environment, and the crust species composition.
authors.affiliation: Institute of Soil and Water Conservation, Chinese Academy of Sciences/State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Yangling 712100, Shaanxi, China. mingjiaowodeshijie@126.com
authors.forename: Jiao
authors.initials: J
authors.lastname: Ming
authors.forename: Yun-Ge
authors.initials: YG
authors.lastname: Zhao
authors.forename: Ming-Xiang
authors.initials: MX
authors.lastname: Xu
authors.forename: Li-Na
authors.initials: LN
authors.lastname: Yang
authors.forename: Ai-Guo
authors.initials: AG
authors.lastname: Wang
mesh_terms: D000531:Altitude; D002681:China; D003247:Conservation of Natural Resources / Q000379:methods*; D017753:Ecosystem; D004784:Environmental Monitoring / Q000379:methods; D006358:Hot Temperature; D009586:Nitrogen Fixation; D009591:Nitrogenase / Q000378:metabolism*; D012987:Soil / Q000737:chemistry*; D014867:Water; D014919:Wind
chemical_list: D012987:Soil; D014867:Water; D009591:Nitrogenase