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ISSN 1556-6757 |
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Volume
2, Issue 2, 2008
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The Impacts of Pasture Degradation on Soil Nutrients and Plant
Compositions in Alpine Grassland, China Ronggui Wu, Holm
Tiessen, Zhi Chen
Abstract
This study investigated the effects of grassland degradation
on plant community composition and soil erosion in the alpine grassland
soil of China. Grasslands were grouped as three categories: lightly
(LDP), moderately (MDP), and heavily degraded pasture (HDP). Soil
samples were collected from 18 sites at seven locations in Chernozemic
soils between elevations of 2600 to 3200 m. Once pasture was heavily
degraded, soil 137Cs activity dropped by 22%. Soil total organic carbon
(TOC), total nitrogen (TN), and effective cation exchangeable capacity (ECEC)
reduced significantly when pasture was heavily degraded. Soil TOC and
ECEC in grass-dominated pasture were slightly higher than those in the
forb-dominated pasture. Achnatherum inebrians dominated pasture resulted
in significantly lower levels of soil TOC and TN. On heavily degraded
pasture, changes in plant species composition were found. More grass and
grass-like plants were observed in LDP, whereas HDP had more forbs and
shrubs. Plant palatability index (PI) decreased from 205 in LDP to 173
in MDP, and then to 151 in HDP, implying that the abundance of more
palatable plants have decreased with pasture degradation, while plants
with lower forage value tended to increase.
Full
Article
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