Three alpine meadows were chosen from the eastern margin of the Qilian Mountain：Polygonum viviparum meadow（P）,Stipa capillata grassland（S）and Rhododendron simsii shrub meadow（R）;LI-8100 A soil CO2 flux auto-mon...Three alpine meadows were chosen from the eastern margin of the Qilian Mountain：Polygonum viviparum meadow（P）,Stipa capillata grassland（S）and Rhododendron simsii shrub meadow（R）;LI-8100 A soil CO2 flux auto-monitoring system and lab analysis were applied to analyze the soil organic carbon density,dynamics of carbon flux,and their relationship with environmental factors.The results showed that different vegetations varied greatly in soil organic carbon density：R 〉 S 〉 P,and the soil carbon density reduced with the increasing depth;soil CO2flux：S 〉 P 〉 R,and sample plot P and S showed unimodal changes.The peak values appeared at 14：00-15：00 p.m.;soil CO2 flux was negatively correlated with near-ground air humidity and carbon content,positively correlated with soil temperature and near-ground air temperature,and showed no obvious correlation with soil moisture.展开更多
Phyllostachys praecox C. D. Chu et C. S. Chao, a favored bamboo shoot species, has been widely planted in recent years. Four stands with different historical management practices were selected for this study to unders...Phyllostachys praecox C. D. Chu et C. S. Chao, a favored bamboo shoot species, has been widely planted in recent years. Four stands with different historical management practices were selected for this study to understand the evolution of soil microbial ecology by determining the effects of a new mulching and heavy fertilization practice on soil quality using microbiological parameters. Compared with the traditional practice (index 1), microbial biomass carbon (MBC) and soil microbial respiration carbon (MRC) with the new management practice significantly decreased (P ＜ 0.01 and P ＜ 0.05,respectively) with 1-2 years of mulching (index 2) and then for continued mulching significantly increased (P ＜ 0.05). The ratios of MBC/TOC (total organic carbon) and MRC/TOC also significantly diminished (P ＜ 0.05) with mulching. The average well color development (AWCD) and Shannon index decreased with mulching time, and the significant decrease(P ＜ 0.05) in Shannon index occurred from index 2 to index 3. The results from a principal components analysis (PCA)showed that the scores of the first principal component for indexes 1 and 2 were significantly larger (P ＜ 0.05) than soils mulched 3-4 years or 5-6 years. Also, the second principal component scores for index 1 were larger than those for index 2, suggesting that the ability of soil microorganisms to utilize soil carbon was decreasing with longer use of the new management practice and causing a deterioration of soil biological properties.展开更多
基金Sponsored by Natural Science Foundation of China(31360569)Key Laboratory of Grassland Ecosystem Program(CYZS-2011007)Modern Agricultural Technical System of Gansu Agricultural University CARS-35
文摘Three alpine meadows were chosen from the eastern margin of the Qilian Mountain：Polygonum viviparum meadow（P）,Stipa capillata grassland（S）and Rhododendron simsii shrub meadow（R）;LI-8100 A soil CO2 flux auto-monitoring system and lab analysis were applied to analyze the soil organic carbon density,dynamics of carbon flux,and their relationship with environmental factors.The results showed that different vegetations varied greatly in soil organic carbon density：R 〉 S 〉 P,and the soil carbon density reduced with the increasing depth;soil CO2flux：S 〉 P 〉 R,and sample plot P and S showed unimodal changes.The peak values appeared at 14：00-15：00 p.m.;soil CO2 flux was negatively correlated with near-ground air humidity and carbon content,positively correlated with soil temperature and near-ground air temperature,and showed no obvious correlation with soil moisture.
文摘Phyllostachys praecox C. D. Chu et C. S. Chao, a favored bamboo shoot species, has been widely planted in recent years. Four stands with different historical management practices were selected for this study to understand the evolution of soil microbial ecology by determining the effects of a new mulching and heavy fertilization practice on soil quality using microbiological parameters. Compared with the traditional practice (index 1), microbial biomass carbon (MBC) and soil microbial respiration carbon (MRC) with the new management practice significantly decreased (P ＜ 0.01 and P ＜ 0.05,respectively) with 1-2 years of mulching (index 2) and then for continued mulching significantly increased (P ＜ 0.05). The ratios of MBC/TOC (total organic carbon) and MRC/TOC also significantly diminished (P ＜ 0.05) with mulching. The average well color development (AWCD) and Shannon index decreased with mulching time, and the significant decrease(P ＜ 0.05) in Shannon index occurred from index 2 to index 3. The results from a principal components analysis (PCA)showed that the scores of the first principal component for indexes 1 and 2 were significantly larger (P ＜ 0.05) than soils mulched 3-4 years or 5-6 years. Also, the second principal component scores for index 1 were larger than those for index 2, suggesting that the ability of soil microorganisms to utilize soil carbon was decreasing with longer use of the new management practice and causing a deterioration of soil biological properties.
