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ARS Home » Pacific West Area » Logan, Utah » Forage and Range Research » Research » Publications at this Location » Publication #316234
Title: Grazing effects on soil characteristics and vegetation of grassland in northern China

Author
item WANG, ZHONGMEI - China Agriculture University
item Johnson, Douglas
item RONG, YUPING - China Agriculture University
item WANG, K - China Agricultural University

Submitted to: Solid Earth
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/27/2015
Publication Date: 1/15/2016
Citation: Wang, Z., Johnson, D.A., Rong, Y., Wang, K. 2016. Grazing effects on soil characteristics and vegetation of grassland in northern China. Solid Earth. 7:55-65.

Interpretive Summary: Large areas of grassland in the agro-pastoral region of northern China were converted into cropland for grain production, and the remaining grasslands are being overgrazed and seriously degraded. The objective of this study was to evaluate how reductions in grazing intensity affect the spatial heterogeneity of soil and vegetation characteristics in grasslands of northern China. Soil heterogeneity and vegetation characteristics were evaluated in areas with no grazing, moderate grazing, and heavy grazing areas in northern China. Reductions in livestock grazing intensity increased the heterogeneity of soil characteristics, and species diversity increased with grazing intensity. Spatial heterogeneity of soil characteristics on northern China's grasslands will remain low with continued overgrazing and result in further grassland degradation.

Technical Abstract: Large areas of grassland in the agro-pastoral region of northern China were converted into cropland for grain producton, and the remaining grasslands are being overgrazed and seriously degraded. The objective of this study was to evaluate how reductions in grazing intensity affect the spatial heterogeneity of soil and vegetation characteristics in grasslands of northern China. Soil heterogeneity and vegetation charactertistics were evaluated for ungrazed (UG), moderate grazing (MG), and heavy grazing (HG) sites in northern China after long-term (~50 years) overgrazing. Reductions in livestock grazing intensity increased the heterogeneity of soil characteristics at a 10-m scale. The ranges of spatial autocorrelation for soil organic C (SOC) and total N were both >120 m at the HG site, which was considerably larger than that at the MG and UG sites with corresponding distances of 17.3 and 20.8 m for the MG site and 25.8 and 15.0 m for the UG site, respectively. This suggested that overgrazing homogenizes SOC and N. Vegetation biomass was greatest at the UG site (220 g m-2) followed by the MG (99 g m-2) and HG (27 g m-2) sites (P<0.05). The non-grass proportion of total biomass increased with grazing intensity, which was 8, 16, and 48% for HG, MG, and UG sites, respectively. Species richness and species diversity also increased with grazing intensity and was 3.6, 5.5, and 5.7 for HG, MG, and UG sites, respectively. Similarly, a diversity index (species diversity) increased with grazing intensity with 0.43, 0.80, and 1.18 for UG, MG, and HG sites, respectively. Spatial heterogeneity of soil characteristics on northern China's grasslands will remain low with continued overgrazing and result in further grassland degradation. Landscape heterogeneity and grassland productivity can be improved with reductions in grazing intensity.