[Objective] The aim was to clear the suitable green manure cropping pat- terns in Xiangxi tobacco-planting areas. [Method] 8 treatments were set to study the effects of the monoculture and mixed cropping of common vet...[Objective] The aim was to clear the suitable green manure cropping pat- terns in Xiangxi tobacco-planting areas. [Method] 8 treatments were set to study the effects of the monoculture and mixed cropping of common vetch （Vicia gigantea Bge.）, perennial ryegrass （Lofium） and rapeseed （Brassica campestris L.） on physi- cal and chemical properties of soil and economic characters of flue-cured tobacco. [Result] （1） Green manure turnover can reduce soil bulk density by 1.08%-8.62%, and the effect of green manure mixed cropping pattern was the best. （2） Green manure turnover also can increase the soil nutrient, soil organic matter, total nitro- gen （N）, total phosphorus （P）, total potassium （K）, alkali-hydrolyzale N, rapidly available P and rapidly available K by 1.44%-6.10%, 0.01-0.12 g/kg, 1.89%- 11.32%, 0.12%-3.56%, 1.06%-11.76%, 0.04%-18.93% and 0.98%-23.12%, respec- tively, and the effect of the monoculture of common vetch was the best.（3） The overall change of soil pH was not obvious.（4）Green manure turnover can increase the yield and output of flue-cured tobacco, and the effect of the monoculture of common vetch was the best. [Conclusion] The monoculture of common vetch can be generalized in the dry land of Xiangxi tobacco-planting areas.展开更多
Most of current studies of deep soil mixing (DSM) methods are focused on the soil strength improvement and soil treatment effectiveness. But the DSM installation leads to excess pore water pressure and soil disturbanc...Most of current studies of deep soil mixing (DSM) methods are focused on the soil strength improvement and soil treatment effectiveness. But the DSM installation leads to excess pore water pressure and soil disturbance, which will bring great harm to adjacent structures, such as shell tunnels and historic buildings. The procedure of excess pore water pressure buildup while large number DSM columns are installed is complicated. In order to find methods to predict and simulate the excess pore water pressure during DSM column installation, the complicated dissipation and buildup of excess pore water pressure through in-situ test are studied in this paper. In-situ test was conducted in soft clay near the Huangpu River in Shanghai. The pore water pressure was investigated by an automatic monitoring system. Test results indicate that the excess pore water pressure induced by one DSM column installation is composed of the compaction pressure and the reversing pressure. The empirical equations of excess pore water pressure dissipation and buildup were built by mathematical fitting methods. A compound method is proposed to simulate the excess pore water pressure due to DSM installation. Using this method to predict the excess pore water pressure in the situ test, results show a well agreement between the prediction and the measurements.展开更多
A kind of mixed bacterial manure was prepared,which was composed of four bacterium,namely,Bacillus megatherium var.phosphaticum,B.mucilaginosus,Azorhizobium sp.and cellulose-decomposing microorganisms.Preservation exp...A kind of mixed bacterial manure was prepared,which was composed of four bacterium,namely,Bacillus megatherium var.phosphaticum,B.mucilaginosus,Azorhizobium sp.and cellulose-decomposing microorganisms.Preservation experiments of the mixed bacterial manure were carried out under different temperature conditions.The results showed that when the temperature was 4,18 and 28 ℃,the colony counts of each preserved bacterium increased until 30 days and then almost all of them began to decline,and the total colony counts of the bacterial manure varied little among 30 days and its growth curve reached a peak and a valley when the temperature was 4 and 38 ℃ respectively.This results suggested that the bacterial manure was optimum to be preserved at 4 ℃ and be kept for 30 days,and the conditions 4—28 ℃ and 10—90 days were the matched ranges for its preservation.Potting experiments showed that at room temperature and the amount of inoculation was ≤5‰,the growth curves of Azorhizobium sp.and cellulose-decomposing microorganisms were very similar and both hadn’t a great change,but that of B.megatherium var.phosphaticum and B.mucilaginosus varied significantly with the increasing amount of inoculation. This suggested that at room temperature,the total colony counts of the bacterial manure would increase when the amount of inoculation was ≤5‰ and reached the highest value 90 days later after soil inoculation.展开更多
基金Supported by Key Project of Hunan Tobacco Monopoly Bureau-"Study an Demonstration of Tobacco-planting Soil Maintenance and Improvement in Xiangx Autonomous Prefecture Tobacco-growing Area"(13-14ZDAa03)the Project o China Tobacco Zhejiang Industrial Co.,Ltd.-"Demonstration and Extension o Tobacco-planting Soil Improvement Using Green Manure"(ZJZY2013B003)~~
文摘[Objective] The aim was to clear the suitable green manure cropping pat- terns in Xiangxi tobacco-planting areas. [Method] 8 treatments were set to study the effects of the monoculture and mixed cropping of common vetch （Vicia gigantea Bge.）, perennial ryegrass （Lofium） and rapeseed （Brassica campestris L.） on physi- cal and chemical properties of soil and economic characters of flue-cured tobacco. [Result] （1） Green manure turnover can reduce soil bulk density by 1.08%-8.62%, and the effect of green manure mixed cropping pattern was the best. （2） Green manure turnover also can increase the soil nutrient, soil organic matter, total nitro- gen （N）, total phosphorus （P）, total potassium （K）, alkali-hydrolyzale N, rapidly available P and rapidly available K by 1.44%-6.10%, 0.01-0.12 g/kg, 1.89%- 11.32%, 0.12%-3.56%, 1.06%-11.76%, 0.04%-18.93% and 0.98%-23.12%, respec- tively, and the effect of the monoculture of common vetch was the best.（3） The overall change of soil pH was not obvious.（4）Green manure turnover can increase the yield and output of flue-cured tobacco, and the effect of the monoculture of common vetch was the best. [Conclusion] The monoculture of common vetch can be generalized in the dry land of Xiangxi tobacco-planting areas.
基金the National Natural Science Foundation of China (No.41172251)
文摘Most of current studies of deep soil mixing (DSM) methods are focused on the soil strength improvement and soil treatment effectiveness. But the DSM installation leads to excess pore water pressure and soil disturbance, which will bring great harm to adjacent structures, such as shell tunnels and historic buildings. The procedure of excess pore water pressure buildup while large number DSM columns are installed is complicated. In order to find methods to predict and simulate the excess pore water pressure during DSM column installation, the complicated dissipation and buildup of excess pore water pressure through in-situ test are studied in this paper. In-situ test was conducted in soft clay near the Huangpu River in Shanghai. The pore water pressure was investigated by an automatic monitoring system. Test results indicate that the excess pore water pressure induced by one DSM column installation is composed of the compaction pressure and the reversing pressure. The empirical equations of excess pore water pressure dissipation and buildup were built by mathematical fitting methods. A compound method is proposed to simulate the excess pore water pressure due to DSM installation. Using this method to predict the excess pore water pressure in the situ test, results show a well agreement between the prediction and the measurements.
文摘A kind of mixed bacterial manure was prepared,which was composed of four bacterium,namely,Bacillus megatherium var.phosphaticum,B.mucilaginosus,Azorhizobium sp.and cellulose-decomposing microorganisms.Preservation experiments of the mixed bacterial manure were carried out under different temperature conditions.The results showed that when the temperature was 4,18 and 28 ℃,the colony counts of each preserved bacterium increased until 30 days and then almost all of them began to decline,and the total colony counts of the bacterial manure varied little among 30 days and its growth curve reached a peak and a valley when the temperature was 4 and 38 ℃ respectively.This results suggested that the bacterial manure was optimum to be preserved at 4 ℃ and be kept for 30 days,and the conditions 4—28 ℃ and 10—90 days were the matched ranges for its preservation.Potting experiments showed that at room temperature and the amount of inoculation was ≤5‰,the growth curves of Azorhizobium sp.and cellulose-decomposing microorganisms were very similar and both hadn’t a great change,but that of B.megatherium var.phosphaticum and B.mucilaginosus varied significantly with the increasing amount of inoculation. This suggested that at room temperature,the total colony counts of the bacterial manure would increase when the amount of inoculation was ≤5‰ and reached the highest value 90 days later after soil inoculation.
