TY - JOUR
T1 - Labile organic C and N mineralization of soil aggregate size classes in semiarid grasslands as affected by grazing management
AU - Wu, Honghui
AU - Wiesmeier, Martin
AU - Yu, Qiang
AU - Steffens, Markus
AU - Han, Xinguo
AU - Kögel-Knabner, Ingrid
N1 - Funding Information:
Acknowledgements The authors would like to thank Yueqin Cheng (ISC-CAS), Angelika Kölbl, Greetje Pronk, and Olivia Kreyling (TU München) for laboratory work, Tabea Dietz and Sigrid Hiesch (CAU TU München) for determination of NH4+and NO3- concentration. This study was funded by the Deutsche Forschungsgemeinschaft (DFG) within the MAGIM project (Forschergruppe 536 MAGIM — Matter fluxes in grasslands of Inner Mongolia as influenced by stocking rate).
PY - 2012/4
Y1 - 2012/4
N2 - Soil labile organic carbon (C) oxidation drives the flux of carbon dioxide (CO 2) between soils and the atmosphere. However, the impact of grazing management and the contribution soil aggregate size classes (ASCs) to labile organic C from grassland soils is unclear. We evaluated the effects of grazing intensity and soil ASC on the soil labile organic C, including CO 2 production, microbial biomass C, and dissolved organic C and nitrogen (N) mineralization in topsoils (0-10 cm) in Inner Mongolia, Northern China. Soil samples were separated into ASCs of 0-630 μm [fine ASC (fASC)], 630-2000 μm [medium ASC (mASC)] and >2000 μm [coarse ASC (cASC)]. The results showed that heavy grazing (HG) and continuous grazing (CG) increased soil labile organic C significantly compared to an ungrazed site since 1999 (UG99) and an ungrazed site since 1979 (UG79). For winter grazing site (WG), no significant differences were found. CO 2 production was highest in cASC, while lowest in fASC. Microbial biomass C and dissolved organic C showed the highest values in mASC and were significantly lower in fASC. Grazing increased N mineralization in bulk soils, while it exhibited complex effects in the three ASCs. The results suggest that the rate of C mineralization was related to the rate of N accumulation. To reduce CO 2 emission and nutrient loss, and to improve soil quality and productivity, a grazing system with moderate intensity is suggested.
AB - Soil labile organic carbon (C) oxidation drives the flux of carbon dioxide (CO 2) between soils and the atmosphere. However, the impact of grazing management and the contribution soil aggregate size classes (ASCs) to labile organic C from grassland soils is unclear. We evaluated the effects of grazing intensity and soil ASC on the soil labile organic C, including CO 2 production, microbial biomass C, and dissolved organic C and nitrogen (N) mineralization in topsoils (0-10 cm) in Inner Mongolia, Northern China. Soil samples were separated into ASCs of 0-630 μm [fine ASC (fASC)], 630-2000 μm [medium ASC (mASC)] and >2000 μm [coarse ASC (cASC)]. The results showed that heavy grazing (HG) and continuous grazing (CG) increased soil labile organic C significantly compared to an ungrazed site since 1999 (UG99) and an ungrazed site since 1979 (UG79). For winter grazing site (WG), no significant differences were found. CO 2 production was highest in cASC, while lowest in fASC. Microbial biomass C and dissolved organic C showed the highest values in mASC and were significantly lower in fASC. Grazing increased N mineralization in bulk soils, while it exhibited complex effects in the three ASCs. The results suggest that the rate of C mineralization was related to the rate of N accumulation. To reduce CO 2 emission and nutrient loss, and to improve soil quality and productivity, a grazing system with moderate intensity is suggested.
KW - Dissolved organic carbon
KW - Inner Mongolia
KW - Microbial biomass carbon
KW - Semiarid grassland
KW - Soil organic carbon
UR - http://www.scopus.com/inward/record.url?scp=84857919360&partnerID=8YFLogxK
U2 - 10.1007/s00374-011-0627-4
DO - 10.1007/s00374-011-0627-4
M3 - Article
AN - SCOPUS:84857919360
SN - 0178-2762
VL - 48
SP - 305
EP - 313
JO - Biology and Fertility of Soils
JF - Biology and Fertility of Soils
IS - 3
ER -