New Zealand Journal of Agricultural Research abstracts
Response of vegetation and soils to desertification of alpine
meadow in the upper basin of the Yellow River, China
Hui Wang1,2
Zheng Gang Guo1,*
Xiang Hong Xu2
Tian Gang Liang1
Ji Zhou Ren1
1College of Pastoral Agriculture Science and Technology
Lanzhou University
Lanzhou City
730020, China
2College of Forestry
Gansu Agricultural University
Lanzhou City, 730070, China
*Corresponding author: zhenggangguo200@hotmail.com
Abstract Alpine meadow plays important
roles in the animal
production and conservation of water resources in the upper basin of
Yellow River. In recent decades, desertification of this alpine meadow
has resulted in changes in vegetation and soil features, as well as
threatening the ecosystem functions and security. A field study was
conducted to explain the response of vegetation pattern and soil
features to desertification of alpine meadows. Results of vegetation
studies indicated that hygrophytes were gradually replaced by
mesophytes, xerophytes, and some annual psammophilous plants, and that
cover and herbaceous biomass decreased along with the progressive
desertification. Vegetation height increased in the slightly
desertified stage, and then decreased in the very severe stage. Species
diversity decreased, suggesting that desertification of alpine meadow
contributed to species loss. This study also indicated that soil
features gradually declined with increasing desertification of alpine
meadow with soil texture becoming coarser and water content decreasing
gradually. Soil bulk density (0–20 cm layer) increased with increasing
desertification, but in the deeper soil (20–40 cm layer) decreased from
original vegetation to the moderately desertified stage, and then
increased after the severely desertified stage. The difference between
the topsoil and the deeper soil in both soil bulk density and soil
moisture was greatest at the moderately desertified stage. Soil organic
matter dramatically reduced with progressive desertification. Soil
nutrients (total N, P and K) decreased greatly due to desertification.
Soil pH (0–20 cm and 20–40 cm) showed no significant differences among
desertification stages. Overall, desertification of alpine meadow
decreased plant diversity, reduced dominance of palatable species and
changed soil physical and chemical properties. Correlation analysis
indicated that vegetation change has been regulated by soil texture,
soil organic matter and soil water.
Keywords coverage; herbaceous biomass;
plant diversity; soil
nutrients; soil physical property
A07027; Online publication date 29 October 2007; Received 13 April
2007; accepted 9 August 2007
New Zealand Journal of Agricultural Research, 2007, Vol. 50:
491–501
0028–8233/07/5004–0491 © The Royal Society of New Zealand 2007
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