New Zealand Journal of Agricultural Research abstracts
Effects of clipping on diversity and above-ground biomass
associated with soil fertility on an alpine meadow in the eastern
region of the Qinghai-Tibetan Plateau
Wenwu Han1,2,3
Yanjiang Luo1
Guozhen Du1*
1Department of Ecology
Lanzhou University
Tianshui Rd 222
Lanzhou 730000
Gansu, PR China
2Lawn Agriculture Technology College
Lanzhou University
Tianshui Rd 222
Lanzhou 730000
Gansu, PR China
3Nam Co Monitoring and Research Station for Multisphere
Interaction
Institute of Tibetan Plateau Research
Chinese Academy of Sciences (CAS)
Beijing 100085
*Author for correspondence: guozdu@lzu.edu.cn
Abstract The objective of this research
was to test the
hypothesis that effects of different clipping regimes on diversity on
an alpine meadow are due to soil fertility. Species richness should be
greatest at an intermediate level of disturbance, e.g., clipping, since
dominance is prevented and the pool of potential colonists is
relatively large. We predict the effects of clipping on species
richness, diversity and above-ground biomass based on the disturbance
hypothesis. A natural pasture was used for the experiment that was a
randomised complete block design with four levels of nutrient input
annually from the 2001 growing season. During 2004, subplots were
clipped to stubble heights of 2, 4 and 10 cm above the soil surface,
with a control. Species richness declined to an average of 6 and 19
species per quadrat for the treatments that were heavily clipped twice,
compared to an average of 11 and 31 species per quadrat in the
unclipped treatment receiving nutrient input of 120 g of fertiliser/m2
and control plots, respectively. Species richness was not altered by
the other clipping treatments at any nutrient level. Species richness
declined in plots with the highest nutrient input and in control plots
with heavy clipping twice, but species richness had no obvious changes
in those plots receiving the intermediate level clipping at all
nutrient levels. Available phosphorus increased significantly with
increased nutrient addition, however soil pH decreased. Available
nitrogen and organic matter did not change significantly with nutrient
addition. The clipping regime contributed to the dominance of
graminoids with increased nutrient input, and the dominant graminoids
assimilated large amounts of available nitrogen and organic matter,
which resulted in the minor changes in available nitrogen in soil.
Keywords above-ground biomass; available
nitrogen; available phosphorus; clipping; nutrient addition;
species richness
A06011; Online publication date 5 July 2007; Received 6 March 2006;
accepted 11 February 2007
New Zealand Journal of Agricultural Research, 2007, Vol. 50:
361–368
0028–8233/07/5003–0361 © The Royal Society of New Zealand 2007
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