摘要
采用碱液吸收法对内蒙古锡林河流域羊草 (L eymus chinensis)草原群落土壤呼吸速率进行了连续 2年的野外测定 ,并通过多元回归手段对其影响因子进行了分析。结果表明 :1) 1998～ 1999年两个生长季羊草群落土壤呼吸速率的季节动态均为单峰型曲线 ,最大值出现在 7月下旬 ;2 ) CO2 释放速率、气温和土壤含水量之间有如下关系 :L n Res=5 .85 96 + 0 .0 12 5 M+ 0 .0 394T+ 0 .0 0 49M× T,R2 =0 .70 96 ,表明约有 70 %的土壤呼吸量变化是由气温和土壤含水量共同决定的 ,其中以温度为主 (Res=2 5 6 .75 T0 .6 5 5 7,R2 =0 .5 779) ,Q1 0 在 2 .0～ 3.0之间 ;3)羊草无放牧群落生长季的土壤呼吸总量在 2 49.4～ 32 0 .7g C.m- 2 .a- 1之间 ,放牧群落在 2 37.0～ 30 5 .6 g C.m- 2 .a- 1之间 ,放牧对土壤呼吸影响不大。
This two year study of CO 2 evolution from Leymus chinensis grassland soil using the alkali absorption method in the Xilin River Basin, examines seasonal trends and CO 2 efflux in relation to grazing and climatic factors.The seasonal pattern of CO 2 evolution rate had a single peak, late July in both 1998 and 1999.Soil respiration was significantly correlated with air temperature, and could be described by the equation of Res=256.75 T 0.6557 ( R 2= 0.5779 , p <0.001).The Q 10 value ranged between 2.5 and 3.0.The relationship between soil respiration rate and the combined effect of temperature and soil water content was LnRes=5.8596+0.0125 M +0.0394 T +0.0049 M × T ( R 2 =0.7096, p <0.001).From observed values and model predictions the soil CO 2 flux ranged from 249.4 gC·m -2 ·a -1 to 320.7 gC·m -2 ·a -1 at the intact study site, and 237.0 gC·m -2 ·a -1 to 305.6 gC·m -2 ·a -1 at the grazed site.From this analysis,and to the extent that other factors were equal,we can conclude that the influence of grazing on soil respiration at the studied area was negligible.
出处
《植物生态学报》
CAS
CSCD
北大核心
2000年第6期680-686,共7页
Chinese Journal of Plant Ecology
基金
国家重大基础研究项目!(G19990 4340 7)
国家自然科学基金重点项目!(39730 110 )
