Biolog, 16S rRNA gene denaturing gradient gel electrophoresis （DGGE）, and phospholipid fatty acid （PLFA） analyses were used to assess soil microbial community characteristics in a chronosequence of tea garden syst...Biolog, 16S rRNA gene denaturing gradient gel electrophoresis （DGGE）, and phospholipid fatty acid （PLFA） analyses were used to assess soil microbial community characteristics in a chronosequence of tea garden systems （8-, 50-, and 90- year-old tea gardens）, an adjacent wasteland, and a 90-year-old forest. Biolog analysis showed that the average well color development （AWCD） of all carbon sources and the functional diversity based on the Shannon index decreased （P 〈 0.05） in the following order： wasteland 〉 forest 〉 tea garden. For the DCCE analysis, the genetic diversity based on the Shannon index was significantly lower in the tea garden soils than in the wasteland. However, compared to the 90-year-old forest, the tea garden soils showed significantly higher genetic diversity. PLFA analysis showed that the ratio of Gram positive bacteria to Cram negative bacteria was significantly higher in the tea garden soils than in the wasteland, and the highest value was found in the 90-year-old forest. Both the fungal PLFA and the ratio of fungi to bacteria were significantly higher in the three tea garden soils than in the wasteland and forest, indicating that fungal PLFA was significantly affected by land-use change. Based on cluster analysis of the soil microbial community structure, all three analytical methods showed that land-use change had a greater effect on soil microbial community structure than tea garden age.展开更多
Soil acidification is an important process in land degradation around the world as well as in China.Acidification of Alfisols was investigated in the tea gardens with various years of tea cultivation in the eastern Ch...Soil acidification is an important process in land degradation around the world as well as in China.Acidification of Alfisols was investigated in the tea gardens with various years of tea cultivation in the eastern China.Cultivation of tea plants caused soil acidification and soil acidity increased with the increase of tea cultivation period.Soil pH of composite samples from cultivated layers decreased by 1.37,1.62 and 1.85,respectively,after 13,34 and 54 years of tea plantation,as compared to the surface soil obtained from the unused land.Soil acidification rates at early stages of tea cultivation were found to be higher than those at the later stages.The acidification rate for the period of 0-13 years was as high as 4.40 kmol H + ha ?1 year ?1 for the cultivated layer samples.Soil acidification induced the decrease of soil exchangeable base cations and base cation saturation and thus increased the soil exchangeable acidity.Soil acidification also caused the decrease of soil cation exchange capacity,especially for the 54-year-old tea garden.Soil acidification induced by tea plantation also led to the increase of soil exchangeable Al and soluble Al,which was responsible for the Al toxicity to plants.展开更多
基金the National Natural Science Foundation of China (Nos.30671207 and 40371063).
文摘Biolog, 16S rRNA gene denaturing gradient gel electrophoresis （DGGE）, and phospholipid fatty acid （PLFA） analyses were used to assess soil microbial community characteristics in a chronosequence of tea garden systems （8-, 50-, and 90- year-old tea gardens）, an adjacent wasteland, and a 90-year-old forest. Biolog analysis showed that the average well color development （AWCD） of all carbon sources and the functional diversity based on the Shannon index decreased （P 〈 0.05） in the following order： wasteland 〉 forest 〉 tea garden. For the DCCE analysis, the genetic diversity based on the Shannon index was significantly lower in the tea garden soils than in the wasteland. However, compared to the 90-year-old forest, the tea garden soils showed significantly higher genetic diversity. PLFA analysis showed that the ratio of Gram positive bacteria to Cram negative bacteria was significantly higher in the tea garden soils than in the wasteland, and the highest value was found in the 90-year-old forest. Both the fungal PLFA and the ratio of fungi to bacteria were significantly higher in the three tea garden soils than in the wasteland and forest, indicating that fungal PLFA was significantly affected by land-use change. Based on cluster analysis of the soil microbial community structure, all three analytical methods showed that land-use change had a greater effect on soil microbial community structure than tea garden age.
基金Supported by the National Nature Science Foundation of China (No. 30872009)the Earmarked Fund for Modern Agro-Industry Technology Research System of China (No. nycytx-23)
文摘Soil acidification is an important process in land degradation around the world as well as in China.Acidification of Alfisols was investigated in the tea gardens with various years of tea cultivation in the eastern China.Cultivation of tea plants caused soil acidification and soil acidity increased with the increase of tea cultivation period.Soil pH of composite samples from cultivated layers decreased by 1.37,1.62 and 1.85,respectively,after 13,34 and 54 years of tea plantation,as compared to the surface soil obtained from the unused land.Soil acidification rates at early stages of tea cultivation were found to be higher than those at the later stages.The acidification rate for the period of 0-13 years was as high as 4.40 kmol H + ha ?1 year ?1 for the cultivated layer samples.Soil acidification induced the decrease of soil exchangeable base cations and base cation saturation and thus increased the soil exchangeable acidity.Soil acidification also caused the decrease of soil cation exchange capacity,especially for the 54-year-old tea garden.Soil acidification induced by tea plantation also led to the increase of soil exchangeable Al and soluble Al,which was responsible for the Al toxicity to plants.
