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Storage and Dynamics of Carbon and Nitrogen in Soil after Grazing Exclusion in Leymus chinensis Grasslands of Northern China
Author(s) -
Wu L.,
He N.,
Wang Y.,
Han X.
Publication year - 2008
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2007.0196
Subject(s) - grazing , soil carbon , chronosequence , agronomy , environmental science , leymus , temperate climate , nitrogen , ecosystem , biomass (ecology) , topsoil , soil water , grassland , soil science , chemistry , biology , ecology , organic chemistry
Land‐use change can lead to changes in soil carbon (C) and nitrogen (N) storage. This study aimed to determine the impact of long‐term grazing exclusion (GE) on soil organic C and total N (TN) storage in the Leymus chinensis grasslands of northern China and to estimate the dynamics of recovery after GE. We investigated the aboveground biomass and soil organic C and TN storage in six contiguous plots along a GE chronosequence comprising free grazing, 3‐yr GE, 8‐yr GE, 20‐yr GE, 24‐yr GE, and 28‐yr GE. Grazing exclusion for two decades increased the soil C and N storage by 35.7 and 14.6%, respectively, in the 0‐ to 40‐cm soil layer. The aboveground net primary productivity and soil C and N storage were the highest with 24‐yr GE and the lowest with free grazing. The storage increased logarithmically with the duration of GE; after an initial rapid increase after the introduction of GE, the storage attained equilibrium after 20 yr. A logarithmic regression analysis revealed 86.8 and 87.1% variation in the soil C storage and 74.2 and 80.7% variation in the soil N storage in the 0‐ to 10‐cm and 0‐ to 40‐cm soil layers, respectively. Based on these results, we suggest that two decades of GE would restore the L. chinensis grasslands from being lightly degraded to a stable productive condition with good soil C and N storage capacity. Our results demonstrated that by implementing GE, the temperate grasslands of northern China could facilitate significant C and N storage on decade scales in the context of mitigating global climate change.