Accurate crop residue resource estimation is important for bioenergy development.This is done by the ratio of residue to grain(R/G),which is usually regarded constant and is widely used for crop residue estimation tho...Accurate crop residue resource estimation is important for bioenergy development.This is done by the ratio of residue to grain(R/G),which is usually regarded constant and is widely used for crop residue estimation though uncertainty is inevitable in practice.In this study,a Monte Carlo algorithm was applied to estimate national crop residue by R/G taken from published reports in China.The estimated result was further mapped in pixels by geographic information system.In2009,the amount of crop residue was found to be 802.32 million tons(Mt),with 679.36 and 947.28 Mt as the lower and upper limits for 95%confidence limits.Chinese crop residue was dominated by rice,wheat,and corn,accounting for74.57%(598.29 Mt).From 1949 to 2009,the amount of crop residue increased by four times,accompanied by component change.The spatial distribution of crop residue in China is markedly heterogeneous.Compared to the shortage of crop residue in northwest China,there is an abundant crop residue of about 334 Mt in eastern China,attracting 90%of the country's electricity or heat generation plants.展开更多
Hydrodynamic, physical, and biochemical processes in the Baiyangdian Lake water environment were analyzed comprehensively. An eutrophication eco- dynamics model including the effects of reed resistance on flow was cou...Hydrodynamic, physical, and biochemical processes in the Baiyangdian Lake water environment were analyzed comprehensively. An eutrophication eco- dynamics model including the effects of reed resistance on flow was coupled with the hydrodynamics governing equations. An improvement on the Water Quality Analysis Simulation Program （WASP, a modeling system intro- duced by the US Environmental Protection Agency） is established, which uses the zooplankton kinetic equation. The model simulates water quality constituents associated with eutrophication in the lake, including phytoplankton, zooplankton, nitrogen, phosphorus, dissolved oxygen, and others. Various kinetic coefficients were calibrated using measured data or information from relevant literature, to study eutrophication in the lake. The values calculated by the calibrated model agree well with field data, including ammonia nitrogen, total nitrogen, total phosphorus and dissolved oxygen. Changes related to nutrition and dissolved oxygen during the processes were simulated. The present model describes the temporal variation of water quality in Baiyangdian Lake with reasonable accuracy. Deviations between model-simulated and observed values are discussed. As an ideal tool for environmental management of the lake, this model can be used to predict its water quality, and be used in research to examine the eutrophication process.展开更多
基金supported by the Key Laboratory of Industrial Ecological and Environmental Engineering[KLIEEE-11-06]Fundamental Research Funds for the Central Universities[DUT11RC(3)83]
文摘Accurate crop residue resource estimation is important for bioenergy development.This is done by the ratio of residue to grain(R/G),which is usually regarded constant and is widely used for crop residue estimation though uncertainty is inevitable in practice.In this study,a Monte Carlo algorithm was applied to estimate national crop residue by R/G taken from published reports in China.The estimated result was further mapped in pixels by geographic information system.In2009,the amount of crop residue was found to be 802.32 million tons(Mt),with 679.36 and 947.28 Mt as the lower and upper limits for 95%confidence limits.Chinese crop residue was dominated by rice,wheat,and corn,accounting for74.57%(598.29 Mt).From 1949 to 2009,the amount of crop residue increased by four times,accompanied by component change.The spatial distribution of crop residue in China is markedly heterogeneous.Compared to the shortage of crop residue in northwest China,there is an abundant crop residue of about 334 Mt in eastern China,attracting 90%of the country's electricity or heat generation plants.
文摘Hydrodynamic, physical, and biochemical processes in the Baiyangdian Lake water environment were analyzed comprehensively. An eutrophication eco- dynamics model including the effects of reed resistance on flow was coupled with the hydrodynamics governing equations. An improvement on the Water Quality Analysis Simulation Program （WASP, a modeling system intro- duced by the US Environmental Protection Agency） is established, which uses the zooplankton kinetic equation. The model simulates water quality constituents associated with eutrophication in the lake, including phytoplankton, zooplankton, nitrogen, phosphorus, dissolved oxygen, and others. Various kinetic coefficients were calibrated using measured data or information from relevant literature, to study eutrophication in the lake. The values calculated by the calibrated model agree well with field data, including ammonia nitrogen, total nitrogen, total phosphorus and dissolved oxygen. Changes related to nutrition and dissolved oxygen during the processes were simulated. The present model describes the temporal variation of water quality in Baiyangdian Lake with reasonable accuracy. Deviations between model-simulated and observed values are discussed. As an ideal tool for environmental management of the lake, this model can be used to predict its water quality, and be used in research to examine the eutrophication process.
