Soil Respiration Response to Different Stocking Rates on Stipa breviflora Griseb. Desert Steppe
Soil surface carbon dioxide flux is a very important component of carbon cycle of terrestrial ecosystems.In order to determine grazing impact on soil respiration rates under different stocking rates,a comparative study of soil respiration was conducted in a Desert Steppe in Inner Mongolia,P.R.China.A randomized complete block design was used with three replications and four grazing treatments:Control (CK),lightly grazed (LG), moderately grazed (MG) and heavily grazed (HG).The stocking rates were 0,0.91,1.82 and 2.71 sheep\5hm-2·half-year-1,for control,LG,MG and HG treatments, respectively.Soil respiration rate,soil temperature,and soil moisture were obtained in each plot by enclosed chamber method in 2004 and 2006.The results showed that soil respiration rate fluctuated from 0.80 μmol·m-2·s-1 to 5.00 μmol·m-2·s-1.Soil respiration rate was sharply decreased with increase of stocking rate (P<0.05).Meanwhile,soil respiration rate increased with increase of relative humidity in an enclosed chamber,but the regression relationship was not significant (P>0.05).Soil respiration rate has a significant decrease in HG treatment compared to CK and LG treatments through two years' treatment.There is no significant effect of time change on soil respiration in different stocking rates.Soil respiration rate was decreased significantly in a high stocking rate,which might be related to low soil moisture and biomass in these sites.Soil moisture plays an important role in CO2 exchange between soil and atmosphere.
carbon dioxidegrazinggrasslandsoil moisturesoil respirationsoil temperature
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NSTL
万方数据
维普
