Responses of grassland vegetation and soil nutrients to desertification
in Qilian Mountains of eastern Qinghai-Tibetan Plateau
Abstract
To explore the change characteristics of vegetation and soil nutrients
in grassland desertification, the study intends to using the method of
replacing space with time, taking temperate steppe (TS), temperate
steppe desert (TSD) and temperate desert (TD) in Qilian mountains as the
research objects, and analyze the change characteristics of vegetation
and soil nutrients replacing succession of grassland desertification.
The study indicated that, from TS, TSD to TD, the total coverage, AGB,
Shannon-Weiner index and richness, total porosity, total N, soil organic
matter, C/N, C/P, N/P, alkaline phosphatase, catalase, sucrase were
decreased, and grass layer height, dominance, soil bulk density and pH
were increased. While the total P, total K and available P were first
increased and then decreased, and were opposite to evenness and urease
enzyme activity change. Meanwhile, the C/N, C/P and N/P of three
grassland types ranged from 5.06-17.27, 2.49-71.94 and 0.50-4.19.
Correlation analysis showed that, except for available P, available K,
and evenness, there was a significant correlation between other
vegetation and soil indicators. In conclusion, in the process of
grassland desertification, grassland vegetation and soil had undergone
significant changes, especially total coverage, AGB, Shannon-Weiner
index, soil bulk density, soil organic matter and total nitrogen. Based
on N/P, the nitrogen was the main factor limiting the productivity of
grassland, and the limitation was more prominent in the process of
grassland desertification.