Fixed field experimental studies are carried out on daily variations of the undis-turbed community and soil respiration fluxes in different phenological phases of 2001―2002 in semiarid Aneurolepidium chinense steppe ...Fixed field experimental studies are carried out on daily variations of the undis-turbed community and soil respiration fluxes in different phenological phases of 2001―2002 in semiarid Aneurolepidium chinense steppe of Inner Mongolia,China using static black chamber method.Corresponding statistical analysis of the contributions of the water-heat factors(air temperature,ground temperature,surface soil water content)and ecological factors(above-ground biomass,underground biomass,litter biomass)to daily variation law of the undisturbed community and soil respiration fluxes as well as differences in daily respiration are also con-ducted.The results indicate that undisturbed community and soil respiration have apparent daily variation laws,daily variation patterns of respiration fluxes during different phenological phases are basically the same,and the variations of environmental factors only exert effect on CO_(2)emission intensities,while the effect on daily variation pattern of grassland CO_(2)emission fluxes is relatively small.The daily total respiration of the undisturbed community in different phenological phases ranges from 1.34―10.13 g·m^(-2);soil daily total respiration ranges from 0.98―5.17 g·m^(-2);both daily variations of undisturbed community and soil respiration fluxes are significantly corre-lated(p<0.05)or extremely significantly correlated(p<0.01)with air temperatures and ground surface temperatures,but the correlativity with the soil temperature at 5 and 10 cm depths is relatively weak;multiple regression analysis indicates that about 80%of the difference in daily respiration of the undisturbed community among different phenological phases is induced by the variation of the aboveground biomass,while the variations of the remaining factors can jointly explain around 20%of the daily respiration variations of the whole grassland ecosystem;about 83%of the soil daily respiration variation of the different phenological phases is caused by 0―20 cm underground biomass.Besides,surface soil water co展开更多
文摘采用静态箱法研究了我国亚热带红壤区农田利用方式 (旱地或水田 )对土壤 CO2 排放及其相关因子的影响 ,并估算了旱地和水田 CO2 的年排放通量。结果表明 ,水田在淹水植稻期 (夏季 ) ,其排放通量明显低于旱地 ,而在非淹水期 (排水落干或休闲期 ) ,其排放通量则显著高于旱地。 CO2 排放通量呈现明显的季节性变异 ,旱地以夏季最高、春秋季次之、冬季最低 ;而水田则以秋季最高、其次是春冬季、夏季最低。土壤温度和湿度分别是影响旱地和水田 CO2 排放的主导因子 ,可将二者与通量的指数关系作为模型 ,分别进行旱地和水田 CO2 排放的估算。经模型估算 ,我国中亚热带旱地和水田红壤 CO2 的年排放通量分别为 1.37和 2 .73kg CO2 / (m2 · a) )。
基金the Statc Key Basic Research Development and Planning Project(Grant No.2002CB412503)the Knowledge Innovation Program of the Chinese Academy of Sciences(Grant No.KZCX1-sw-01-04)the Knowl-edge Innovation Project of the Institute of Geographic Sciences and Natural Resources Research,CAS(Grant No.CXIOG-E01-03-01).
文摘Fixed field experimental studies are carried out on daily variations of the undis-turbed community and soil respiration fluxes in different phenological phases of 2001―2002 in semiarid Aneurolepidium chinense steppe of Inner Mongolia,China using static black chamber method.Corresponding statistical analysis of the contributions of the water-heat factors(air temperature,ground temperature,surface soil water content)and ecological factors(above-ground biomass,underground biomass,litter biomass)to daily variation law of the undisturbed community and soil respiration fluxes as well as differences in daily respiration are also con-ducted.The results indicate that undisturbed community and soil respiration have apparent daily variation laws,daily variation patterns of respiration fluxes during different phenological phases are basically the same,and the variations of environmental factors only exert effect on CO_(2)emission intensities,while the effect on daily variation pattern of grassland CO_(2)emission fluxes is relatively small.The daily total respiration of the undisturbed community in different phenological phases ranges from 1.34―10.13 g·m^(-2);soil daily total respiration ranges from 0.98―5.17 g·m^(-2);both daily variations of undisturbed community and soil respiration fluxes are significantly corre-lated(p<0.05)or extremely significantly correlated(p<0.01)with air temperatures and ground surface temperatures,but the correlativity with the soil temperature at 5 and 10 cm depths is relatively weak;multiple regression analysis indicates that about 80%of the difference in daily respiration of the undisturbed community among different phenological phases is induced by the variation of the aboveground biomass,while the variations of the remaining factors can jointly explain around 20%of the daily respiration variations of the whole grassland ecosystem;about 83%of the soil daily respiration variation of the different phenological phases is caused by 0―20 cm underground biomass.Besides,surface soil water co
