Because of the distinction of soil property and humus content, soil water content is not ideal to indicate whether it is suitable to the growth of plant. Mainly based on the PF-a numerical value denoting the water reg...Because of the distinction of soil property and humus content, soil water content is not ideal to indicate whether it is suitable to the growth of plant. Mainly based on the PF-a numerical value denoting the water regime of soil and connected with the growth of plant, the study combined the moisture percentage of soil with PF to research in quantity the interrelation between the moisture percentage and PF in different succession phases of subalpine dark coniferous forest in Gongga Mountain. The results showed that: (1) In the same PF value, the moisture percentage in humus horizon increased gradually with the devel-opment of the succession of the dark coniferous forest; The moisture percentage of over-mature forest was the highest and>mature forest>half-mature forest>young growth forest; (2) With the increase of soil depth, the soil bulk density increased and the moisture percentage decreased, but the difference in the percentage of moisture was not notable in different succession phases. (3) In different succession series, the vegetation affected the soil water characteristics by increasing the soil organic matter, improving the soil construction, receding the soil bulk density and enhancing the soil porosity; (4) The humus horizon of the dark coniferous forest soil has the highest water holding capability in this region.展开更多
The static closed chamber technique is used in the study on the CH4 and N2O fluxes from the soils of primeval Abies fabri forest, the succession Abies fabri forest and the clear-cut areas of mid-aged Abies fabri fores...The static closed chamber technique is used in the study on the CH4 and N2O fluxes from the soils of primeval Abies fabri forest, the succession Abies fabri forest and the clear-cut areas of mid-aged Abies fabri forest in the Gongga Mountain from May 1998 to September 1999. The results indicate the following: (i) The forest soil serves as the source of atmospheric N2O at the three measurement sites, while the fluxes of CH4 are all negative, and soil is the sink of atmospheric CH4. The comparative relations of N2O emissions between the three sites are expressed as primeval Abies fabri forest > clear-cut areas > succession Abies fabri forest, and those of CH4 consumption fluxes are primeval Abies fabri forest > succession Abies fabri forest > clear-cut areas. (ii) Signifi-cant seasonal variations of N2O emission at various sites were observed, and two emission peaks of N2O occurr during summer (July—August) and spring (February—March), whereas N2O emission is relatively low in winter and spring (mid March—April). Seasonal variations of CH4 consumption at each measurement site fluctuate drastically with unclear regularities. Generally, CH4 consumption fluxes of succession Abies fabri forest and clear-cut areas are higher from mid May to late July but lower in the rest of sampling time, while the CH4 flux keeps a relatively high value even up to Sep-tember in primeval Abies fabri forest. In contrast to primeval Abies fabri forest, the CH4 absorbabili-ties of succession Abies fabri forest and clear-cut areas of mid-aged Abies fabri forest are weaker. Particularly, the absorbability of the clear-cut areas is even weaker as compared with the other two sites, for the deforestation reduces the soil absorbability of atmospheric CH4. (iii) Evident diurnal variation regularity exists in the N2O emissions of primeval Abies fabri forest, and there is a statistic positive correlation between the fluxes of N2O and air temperature (R=0.95, n=11, <0.01), and also the soil temperature of 5-cm layer (R=0.81, n=11, < 0.01), whereas the CH4 diurnal variation regularities are unclear and have no significant correlation with the soil temperature of 5-cm layer and air temperature.展开更多
The species richness of herb layer was investigated among 43 plots of forest vegetation in the eastern Zhongtiao Mountain, in southern Shanxi Province, China. The forest vegetation was divided into two major vegetatio...The species richness of herb layer was investigated among 43 plots of forest vegetation in the eastern Zhongtiao Mountain, in southern Shanxi Province, China. The forest vegetation was divided into two major vegetation types such as the deciduous forest and the coniferous forest by the two-way indicator species analysis （TWINSPAN）. The species richness of herb layer was fitted in the topographic and soil feature factors, as well as the topographic relative moisture index （TRMI） by the generalized linear models （GLM）. The results showed that canopy cover and altitude were the most significant environmental factors. Soil pH value and soil nutrients index such as total N, organic matter content had no significant influence. The effect of environment factors on species richness of herb layer had significant difference in vegetation types. For the broad-leaved forest, litter depth and TRMI were the important environment factors. For the coniferous forest, soil clay content was another important environment factor. The range of environmental gradient such as altitude may contribute to the difference.展开更多
基金The Development Plan of the State Key Fundamental Research of China (973), contract No. 2000046807 and by Knowledge Innovation Project of the Chinese Academy of Sciences (KZCX2-405)
文摘Because of the distinction of soil property and humus content, soil water content is not ideal to indicate whether it is suitable to the growth of plant. Mainly based on the PF-a numerical value denoting the water regime of soil and connected with the growth of plant, the study combined the moisture percentage of soil with PF to research in quantity the interrelation between the moisture percentage and PF in different succession phases of subalpine dark coniferous forest in Gongga Mountain. The results showed that: (1) In the same PF value, the moisture percentage in humus horizon increased gradually with the devel-opment of the succession of the dark coniferous forest; The moisture percentage of over-mature forest was the highest and>mature forest>half-mature forest>young growth forest; (2) With the increase of soil depth, the soil bulk density increased and the moisture percentage decreased, but the difference in the percentage of moisture was not notable in different succession phases. (3) In different succession series, the vegetation affected the soil water characteristics by increasing the soil organic matter, improving the soil construction, receding the soil bulk density and enhancing the soil porosity; (4) The humus horizon of the dark coniferous forest soil has the highest water holding capability in this region.
基金This work was supported by the National Natural Sciences Foundation of China (Grant No. 49971005) and the Key Innovational Program of Chinese Academy of Sciences (Grant No. KZCX1-SW-01-04) together with the Innovational Project of the Institute of Geogra
文摘The static closed chamber technique is used in the study on the CH4 and N2O fluxes from the soils of primeval Abies fabri forest, the succession Abies fabri forest and the clear-cut areas of mid-aged Abies fabri forest in the Gongga Mountain from May 1998 to September 1999. The results indicate the following: (i) The forest soil serves as the source of atmospheric N2O at the three measurement sites, while the fluxes of CH4 are all negative, and soil is the sink of atmospheric CH4. The comparative relations of N2O emissions between the three sites are expressed as primeval Abies fabri forest > clear-cut areas > succession Abies fabri forest, and those of CH4 consumption fluxes are primeval Abies fabri forest > succession Abies fabri forest > clear-cut areas. (ii) Signifi-cant seasonal variations of N2O emission at various sites were observed, and two emission peaks of N2O occurr during summer (July—August) and spring (February—March), whereas N2O emission is relatively low in winter and spring (mid March—April). Seasonal variations of CH4 consumption at each measurement site fluctuate drastically with unclear regularities. Generally, CH4 consumption fluxes of succession Abies fabri forest and clear-cut areas are higher from mid May to late July but lower in the rest of sampling time, while the CH4 flux keeps a relatively high value even up to Sep-tember in primeval Abies fabri forest. In contrast to primeval Abies fabri forest, the CH4 absorbabili-ties of succession Abies fabri forest and clear-cut areas of mid-aged Abies fabri forest are weaker. Particularly, the absorbability of the clear-cut areas is even weaker as compared with the other two sites, for the deforestation reduces the soil absorbability of atmospheric CH4. (iii) Evident diurnal variation regularity exists in the N2O emissions of primeval Abies fabri forest, and there is a statistic positive correlation between the fluxes of N2O and air temperature (R=0.95, n=11, <0.01), and also the soil temperature of 5-cm layer (R=0.81, n=11, < 0.01), whereas the CH4 diurnal variation regularities are unclear and have no significant correlation with the soil temperature of 5-cm layer and air temperature.
基金This study was supported by the National Natural Science Foundation of China （No. 40271047）.
文摘The species richness of herb layer was investigated among 43 plots of forest vegetation in the eastern Zhongtiao Mountain, in southern Shanxi Province, China. The forest vegetation was divided into two major vegetation types such as the deciduous forest and the coniferous forest by the two-way indicator species analysis （TWINSPAN）. The species richness of herb layer was fitted in the topographic and soil feature factors, as well as the topographic relative moisture index （TRMI） by the generalized linear models （GLM）. The results showed that canopy cover and altitude were the most significant environmental factors. Soil pH value and soil nutrients index such as total N, organic matter content had no significant influence. The effect of environment factors on species richness of herb layer had significant difference in vegetation types. For the broad-leaved forest, litter depth and TRMI were the important environment factors. For the coniferous forest, soil clay content was another important environment factor. The range of environmental gradient such as altitude may contribute to the difference.
