Responses of grassland vegetation and soil nutrients to
desertification in Qilian Mountains of eastern Qinghai-Tibetan
Plateau
Qiang Li; Guoxing He; Degang Zhang; Xiaoni Liu11Corresponding
author. TEL:13809318054
E-mail address: liuxn@gsau.edu.cn (Liu Xiaoni).
(College of Grassland Science, Gansu Agricultural University/Key
Laboratory of Grassland Ecosystem of the Ministry of Education, Lanzhou
730070, PR China)
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.
Keywords: Qilian mountains; desertification; grassland; soil
nutrient.