Oil reservoirs with low permeability and porosity that are in the middle and late exploitation periods in China's onshore oil fields are mostly in the high-water-cut production stage.This stage is associated with sev...Oil reservoirs with low permeability and porosity that are in the middle and late exploitation periods in China's onshore oil fields are mostly in the high-water-cut production stage.This stage is associated with severely non-uniform local-velocity flow profiles and dispersed-phase concentration(of oil droplets) in oil-water two-phase flow,which makes it difficult to measure water holdup in oil wells.In this study,we use an ultrasonic method based on a transmission-type sensor in oil-water two-phase flow to measure water holdup in lowvelocity and high water-cut conditions.First,we optimize the excitation frequency of the ultrasonic sensor by calculating the sensitivity of the ultrasonic field using the finite element method for multiphysics coupling.Then we calculate the change trend of sound pressure level attenuation ratio with the increase in oil holdup to verify the feasibility of the employed diameter for the ultrasonic sensor.Based on the results,we then investigate the effects of oildroplet diameter and distribution on the ultrasonic field.To further understand the measurement characteristics of the ultrasonic sensor,we perform a flow loop test on vertical upward oilwater two-phase flow and measure the responses of the optimized ultrasonic sensor.The results show that the ultrasonic sensor yields poor resolution for a dispersed oil slug in water flow(D OS/W flow),but the resolution is favorable for dispersed oil in water flow(D O/W flow) and very fine dispersed oil in water flow(VFD O/W flow).This research demonstrates the potential application of a pulsed-transmission ultrasonic method for measuring the fraction of individual components in oil-water two-phase flow with a low mixture velocity and high water cut.展开更多
Western Liaoning Province is characterized by huge areas of lowly-efficient Chinese pine (Pinus tabulaeformis Carr.) pure plantations. How to transform these plantations has become an increasingly significant manageme...Western Liaoning Province is characterized by huge areas of lowly-efficient Chinese pine (Pinus tabulaeformis Carr.) pure plantations. How to transform these plantations has become an increasingly significant management problem. In this study, the authors summarized the approaches, which are based on close-to-nature silvicultural system, to transform the pure pine plantations. Native broadleaved trees were planted in three methods: 1) after strip clearcutting, 2) after patch clearcutting; 3) on the open forestland and the forest edge. The transformation targets and the selection of tree species were expatiated in this paper. The key techniques and their application conditions for each method were analyzed and discussed. Through investigation and contrastive analysis, the assessment was made to the stands transformed by strip method. Results showed that the mixed stands at 16 years after transformation had an obvious layered structure and the species richness of understorey vegetation increased by 23.5%–52.9%. Soil enzyme activities of urease, phosphatase and sucrase increased by 6%–142%, 46%–99% and 31%–200%, respetively. Moreover, the transformed stands could effectively control the occurrence of pine caterpillars in plantations. Consequently the transformations enhanced the function of soil and water conservation. Keywords Pinus tabulaeformis - Monoculture - Transformation - Principles and methods - Assessment CLC number S791.254 - S727.22 Document code A Foundation item: This research was supported by grants from the Chinese Academy of Sciences (KZCX3-SW-418), National Natural Science Foundation of China (30100144), and National Key Technologies R & D Program of China (96-007-01-06).Biography: ZENG De-hui (1965-), male, Ph.D. professor in the Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, P. R. ChinaResponsible editor: Zhu Hong展开更多
[Objective] This study aimed to explore the relationship between different forest types and water conservation function. [Method] Based on field survey and experimental analysis, water conservation function of four ty...[Objective] This study aimed to explore the relationship between different forest types and water conservation function. [Method] Based on field survey and experimental analysis, water conservation function of four typical forest stands in Jinyun Mountain of Chongqing was explored, including conifer-broadleaved mixed for- est, evergreen broad-leaved forest, bamboo forest and shrub forest. [Result] The re- sults showed that the order of saturated water storage capacity of soil in four forest stands was shrub forest (266.48 mm) 〉 conifer-broadleaved mixed forest (190.40 mm) 〉 evergreen broad-leaved forest (186.80 mm) 〉 bamboo forest (174.80 mm); the order of maximum water-holding capacity of litter was shrub forest (8.06 mm) 〉 conifer-broadleaved mixed forest (4.71 mm) 〉 evergreen broad-leaved forest (4.32 mm) 〉 bamboo forest (3.34 mm); the order of canopy interception in various forest stands was conifer-broadleaved mixed forest (16.15%) 〉 evergreen broad-leaved for- est (14.70%) 〉 bamboo forest (12.64%). [Conclusion] The study had great signifi- cance to rational manage forest resources, improve water environment and realize scientific management and use of water resources.展开更多
[Objective]The aim of this study was to select tartary buckwheat material with better health function.[Method]Used 35 kinds of tartary buckwheat as experimental materials,and the water holding capacity and expansion c...[Objective]The aim of this study was to select tartary buckwheat material with better health function.[Method]Used 35 kinds of tartary buckwheat as experimental materials,and the water holding capacity and expansion capacity had been determined.[Result] The water holding capacity of 35 kinds of tartary buckwheat will change in the range of 248.5%-341.4% with an average of 283.0%(the holding capacity of T324 was the highest),while the change of expansion capacity changed between 0.50 and 1.50 ml/g with an average of 1.05 ml/g(the expansion capacity of T463 was the highest).[Conclusion]This study had provided theoretical basis for screening better tartary buckwheat variety and its application.展开更多
Rational development and utilization of hilly land is an effective measure for raising land productivity, developing countryside economy, increasing peasants' income, conserving soil and water, and improving eco-envi...Rational development and utilization of hilly land is an effective measure for raising land productivity, developing countryside economy, increasing peasants' income, conserving soil and water, and improving eco-environment. The growth and root distribution of mulberry trees were studied. Various indexes including soil physical characters and hydrological status, water infiltration rate, water and soil loss and soil erosion amount were tested. The results indicated that mulberry trees had the effects of intercepting rainfall, improving soil infiltration rate, decreasing soil erosion amount, and conserving water and soil展开更多
Water and soil conservation is an important part of eco-civilization con-struction. It is a major part of eco-construction and lifeline of social and economy development. Therefore, water and soil conservation is of g...Water and soil conservation is an important part of eco-civilization con-struction. It is a major part of eco-construction and lifeline of social and economy development. Therefore, water and soil conservation is of great significance in maintaining eco-safety. The research concluded status quo and characters of water and soil losses in China and analyzed water and soil conservation and construction of eco-civilization from the perspectives of water and soil conservation and con-struction of eco-civilization.展开更多
A study was conducted to determine the characters of soil structure in different water and soil conservation forests in Keshan County,northwest of Heilongjiang Province,China.The soil bulk density,the ratio of non-cap...A study was conducted to determine the characters of soil structure in different water and soil conservation forests in Keshan County,northwest of Heilongjiang Province,China.The soil bulk density,the ratio of non-capillary porosity and capillary porosity(NCP/CP),and the generalized soil structure index(GSSI) were measured for Fraxinus mandshurica,Larix gmelini,Pinus sylvestris var.mongolica,and Picea koraiensis plantations as well as the abandoned land(as control) adjacent to the forests in typical black soil region.Results show that at soil depth of 0–30cm,the soil bulk density of F.mandshurica forest and L.gmelini forest was lower than that of P.sylvestris var.mongolica forest and P.koraiensis forest,with the relative decrease of 8.04%–11.01%.The soil bulk density of L.gmelini forest was significantly different from that of the P.sylvestris var.mongolica forest and P.koraiensis forest.The NCP/CP values of the four types of plantations were all higher(59.75%–128.82% relatively) than that of abandoned land(p〈0.05),indicating that the soil aeration and permeability under forest were enhanced,especially under L.gmelini forest.GSSI values of the four types of forests were also relatively higher(2.98%–4.36%) than abandoned land(p〈0.05),indicating that those soil and water conservation forests,especially the F.mandshurica forest and P.koraiensis forest,can promote soil condition to approximate ideal soil structure.The result of this study can provide theoretical basis for scientifically evaluating the effects of vegetation restoration on soil quality in typical black soil region.展开更多
With economy development,human destruction of eco-environment is deteriorating,which has become a key treatment nationwide.What's more,eco-environment construction is proceeding and multi-eco-environment projects are...With economy development,human destruction of eco-environment is deteriorating,which has become a key treatment nationwide.What's more,eco-environment construction is proceeding and multi-eco-environment projects are developing.Water and soil conservation and eco-environment construction should be a strategic task long-term insisted on,which is a part of agricultural construction.The research analyzed the relationship between water and soil conservation with eco-environment,concluded the process of ecological civilization construction in promoting water and soil conservation,and proposed countermeasures,laying foundation for water and soil conservation and ecological construction.展开更多
The concept,merits and domestic project examples of ecological disposal technique of dispersal sewage were introduced in detail.It was pointed out that the ecological disposal of dispersal sewage was investment-saved,...The concept,merits and domestic project examples of ecological disposal technique of dispersal sewage were introduced in detail.It was pointed out that the ecological disposal of dispersal sewage was investment-saved,energy consumption-reduced and ecological balance-protected advanced technology.This technology was suitable for small community,dispersal units and agencies,villages and other regions without pipe network pervaded and an available approach for solving present environment-protection problems and keeping sustainable development in China.展开更多
[Objective] This study was to provide theoretical basis for getting sustainable development of rural energy in Tibet into reality.[Method] By reviewing the rural energy resources in Tibet,we analyzed the characteristi...[Objective] This study was to provide theoretical basis for getting sustainable development of rural energy in Tibet into reality.[Method] By reviewing the rural energy resources in Tibet,we analyzed the characteristics and potential of rural biomass utilization in Tibet,and further put forward the sustainable countermeasures on the firewood substitution in Tibet.[Results] Renewable energies including hydraulic,geothermal,solar and wind resources are abundant in Tibet,while there is just a few of fossil energy resources such as oil and coal,with uneven distribution and poor exploration conditions.Traditional consumption of biomass energy resource accounts for a large proportion of the total energy consumption in Tibetan rural districts,which causes potential damage to the fragile ecological environment on the Tibetan Plateau.The excessive use of biomass energy destroyed the vegetation and evoked the environment deterioration such as the intensification of the water and soil loss and the declining of the soil fertility.[Conclusion] It is essential for Tibet to change its rural energy consumption structure,implement the Tibetan firewood alternative energy strategy and try to make full use of renewable energy such as solar energy,wind energy,hydro-energy instead of native vegetation and animal's droppings in order to reduce the adverse impacts of the irrational energy consumption on the ecological environment in Tibet.展开更多
Ridge tillage, which is a very common and important tillage measure in the black soil area of northeast China, has some soil and water conservation bene- fits, but has little attention. It is very important to explore...Ridge tillage, which is a very common and important tillage measure in the black soil area of northeast China, has some soil and water conservation bene- fits, but has little attention. It is very important to explore the spatial distribution of the ridge direction of the arable land and its soil and water conservation benefits in different terrain conditions in the black soil area. So Binxian County of Heilongjiang Province was selected as the study area, and 168 field investigation units were ex- tracted by stratified sampling method and investigated. According to equations of slope gradient factor and slope gradient in ridge direction, and based on the soft- ware of Arcmap, SPSS and Excel, the investigation data of soil and water loss in Binxian County were analyzed and counted, The results show that in plain, hilly and mountainous areas, the average ground slope gradients are 1.92°, 6.20° and 8.27° respectively, and the average slope gradients along ridge direction are 1.33°, 4.52°and 6.45° respectively, which account for about 70%, 73% and 78% of the average ground slope gradients in the same terrain condition; the relative quantities of soil erosion in the present ridge tillage condition account for about 55%, 69% and 67% respectively of that in down-slope ridge tillage conditions, so the present ridge tillage has obviously relative soil and water conservation benefits. Based on these results, the reasons of the present ridge tillage status were analyzed, and some reform measures were proposed. The results could not only help to comprehend the spatial distribution and soil and water conservation benefits of ridge tillage in the black soil area of Northeast China, but also provide scientific references for the layout of local soil and water conservation measures.展开更多
The fiscal sustainability of China and the United States is of major concern globally. Based on comparative data analysis, this paper reveals that the government debt level of both countries is within the normal range...The fiscal sustainability of China and the United States is of major concern globally. Based on comparative data analysis, this paper reveals that the government debt level of both countries is within the normal range. Robust growth prospects of both countries will also vigorously support their future mitigation of government debt level. Comparatively speaking, China's government debt level is healthy and, despite extensive concerns, even its local government debt is not very high. The assessment that China may encounter a crisis is not supported by evidence. Yet in the long run, both countries will face pressures from increased fiscal spending on elder care and healthcare stemming from an ageing population, which will threaten their fiscal sustainability. These challenges require both countries to speed up reforms of elder care and healthcare. Specifically, China needs to focus on elder care reforms and the US should attach more importance to healthcare reforms.展开更多
Taihu Lake area is one of the most developed areas in agricultural production. Application of fertilizers and pesticides in large quantities greatly aggravate environmental pollution of this area, and water pollution ...Taihu Lake area is one of the most developed areas in agricultural production. Application of fertilizers and pesticides in large quantities greatly aggravate environmental pollution of this area, and water pollution has worsened to an unbearable condition. Two sampling farms (respectively 1 hm2) under rape-rice rotation and wheat-rice rotation were selected as studied ecosystem and a 5-yr-old Poplar forest and 8-yr-old Metasequoia forest were chosen in the selected areas. By collecting samples of Nitrogen, Phosphorus in water, crops and underground of forest, the transfer and loss of N and P (main water pollutants) in faming ecosystem were studied, and the effects of forest belts on non-point source pollution of agricultural lands was analyzed. The results indicated that the transfer and loss of N and P vary with means of rotation, types of crops and the amount of fertilizer application. Buffering forest belts betweens farmlands and ditches can effectively stop and purify such elements as N and P in soil runoffs, thus controlling non-point source pollution of agricultural lands. When the width ratio of farmland to forest belt is 100 to 40, 50.05% losing N, 29.37% losing P can be absorbed by forest under rape-rice rotation and 30.98% N, 86.73% P can be absorbed by forest under wheat-rice rotation. When the width ratio of farmland to forest belt is 150 to 40, 33.37% losing N, 19.58% losing P can be absorbed by the forest under rape-rice rotation, and under wheat-rice rotation 20.65% lost N and 57.82% lost P can be absorbed. There is only some purification effect when the width ration of farmland to forest belt is 200 to 40. Based on model of buffering forest belts, the width ratio of farmland to forest is determined between 100 to 40 and 150 to 40, because it not only can purify water, but also occupy less farmland. It is suggested that Poplars, with the characteristics of fast-growing and high value, are suitable to be planted as shelter-forest in Taihu Lake Watershed.展开更多
[Objective] The paper was to study and modify non-limiting water range (NLWR) of soil. [Method] The water content when total soil water potential was -0.3 MPa or soil mechanical resistance was 0.85 MPa was selected ...[Objective] The paper was to study and modify non-limiting water range (NLWR) of soil. [Method] The water content when total soil water potential was -0.3 MPa or soil mechanical resistance was 0.85 MPa was selected as the lower limit of NLWR to replace the original water content of permanent wilting point or the water content under soil mechanical resistance of 2.0 MPa. NLWR could be calculated us-ing the minimum value of upper limit minus the maximum value of lower limit. [Re-sult] Compared with original NLWR or least limiting water range (LLWR), the modi-fied NLWR had more practical significance. When Db〉Db-thr, soil physical properties hindered the growth of crops, so the soil should be improved; when Db〉Db-thr, soil physical properties hindered the growth of crops, so-the soil should be improved; wtlen Db〈Db-thr, as long as the soil water content is within NLWR, soil physical properties had no effect on crop growth. NLWR at this time could be used as the basis for irrigation man- agement in farmland. [Conclusion] The study provides theoretical support and scientific basis for relevant researches about evolution rule and regulatory mechanisms of soil physical quality, relationship between soil physical quality and crop growth and yield, water-fertilizer-salt management of soil.展开更多
[Objective] This study aimed to investigate the effect of water stress on stay green of Yunge F2 generation. [Method] Total 26 sugarcane innovative germplasm materials of Yunge F2 generation, along with their female p...[Objective] This study aimed to investigate the effect of water stress on stay green of Yunge F2 generation. [Method] Total 26 sugarcane innovative germplasm materials of Yunge F2 generation, along with their female parent, were selected as the experimental materials. Based on the observation on appearance of stray green and other five physiological and biochemical indexes, the drought resis- tance of the experimental materials was evaluated comprehensively by subordinate function method, grey relational analysis, and cluster analysis. [Result] The rank of drought resistance of the experimental materials was not exactly the same between subordinate function method and grey relational analysis. However, the drought .re- sistance evaluation results by isometric range-based cluster analysis were consistent with those by the two foregoing methods except Yunge F2 11-68 and Yunge F1 11- 254. At the Euclidean distance of 2.00, the tested materials were classified into four groups. The first group included 8 drought-strongly resistant materials, the third group included 6 drought-moderately resistant materials, the fourth group included 3 drought-poorly resistant materials, and the second group included drought-strongly resistant and drought-moderately resistant materials. The drought resistance coeffi- cients of green leaf numberLtotal leaf number and top four leaves chlorophyll content showed significantly positive correlation with drought resistance comprehensive eval- uation value, thus green leaf number/total leaf number and top four leaves chloro- phyll content could be used as the evaluation indexes of drought resistance in sug- arcane. [Conclusion] The excellent materials possess strong drought resistance and good green holding performance, such as Yunge F2 11-159, can be used as crucial parents and basic germplasm materials in drought resistance breeding of sugarcane. 7展开更多
[Objective] This comparative experiment was to explore the soil loss con- trol effects under cultivation combination of different soil and vegetation types, and to provide scientific basis for the upcoming pilot proje...[Objective] This comparative experiment was to explore the soil loss con- trol effects under cultivation combination of different soil and vegetation types, and to provide scientific basis for the upcoming pilot project of ecological recovery. [Method] Both the rudiment of water locomotion functioned by micro-landscape structures and different spatial combinations of various landscape constituents are considered, thus, the combination of multi-soil type, crop species and site conditions is designed in three different experimental sites. [Result] Soil loss estimates in experiments in South Wello significantly depended on various soil type, slope, vegetation and type of con- servation structure; grass cover tremendously reduces soil loss; legume cultivation performed better than cereal cultivation in soil loss control. [Conclusion] By conduct- ing the data analysis of the experiment, a scientific reference is proposed to the agri- culture planting and protective mode for the alleviation of water and soil loss in Amhara Region, Ethiopia.展开更多
Remote sensing techniques and geographic information systems offer a good means of collecting and manipulating the data required for assessing conservation practices. A method for automatic generation of most of the d...Remote sensing techniques and geographic information systems offer a good means of collecting and manipulating the data required for assessing conservation practices. A method for automatic generation of most of the data required by the Agricultural Non point Source erosion model is developed from three sources:(1) file with contour lines from the topographic maps(TM), (2) soil mapping units from the soil surveys, and (3)land cover from land sat TM image classification.展开更多
基金supported by the National Natural Science Foundation of China(Nos.51527805,11572220 and 41174109)
文摘Oil reservoirs with low permeability and porosity that are in the middle and late exploitation periods in China's onshore oil fields are mostly in the high-water-cut production stage.This stage is associated with severely non-uniform local-velocity flow profiles and dispersed-phase concentration(of oil droplets) in oil-water two-phase flow,which makes it difficult to measure water holdup in oil wells.In this study,we use an ultrasonic method based on a transmission-type sensor in oil-water two-phase flow to measure water holdup in lowvelocity and high water-cut conditions.First,we optimize the excitation frequency of the ultrasonic sensor by calculating the sensitivity of the ultrasonic field using the finite element method for multiphysics coupling.Then we calculate the change trend of sound pressure level attenuation ratio with the increase in oil holdup to verify the feasibility of the employed diameter for the ultrasonic sensor.Based on the results,we then investigate the effects of oildroplet diameter and distribution on the ultrasonic field.To further understand the measurement characteristics of the ultrasonic sensor,we perform a flow loop test on vertical upward oilwater two-phase flow and measure the responses of the optimized ultrasonic sensor.The results show that the ultrasonic sensor yields poor resolution for a dispersed oil slug in water flow(D OS/W flow),but the resolution is favorable for dispersed oil in water flow(D O/W flow) and very fine dispersed oil in water flow(VFD O/W flow).This research demonstrates the potential application of a pulsed-transmission ultrasonic method for measuring the fraction of individual components in oil-water two-phase flow with a low mixture velocity and high water cut.
基金This research was supported by grants from the Chinese Academy of Sciences (KZCX3-SW-418) National Natural Science Founda-tion of China (30100144)and National Key Technologies R & D
文摘Western Liaoning Province is characterized by huge areas of lowly-efficient Chinese pine (Pinus tabulaeformis Carr.) pure plantations. How to transform these plantations has become an increasingly significant management problem. In this study, the authors summarized the approaches, which are based on close-to-nature silvicultural system, to transform the pure pine plantations. Native broadleaved trees were planted in three methods: 1) after strip clearcutting, 2) after patch clearcutting; 3) on the open forestland and the forest edge. The transformation targets and the selection of tree species were expatiated in this paper. The key techniques and their application conditions for each method were analyzed and discussed. Through investigation and contrastive analysis, the assessment was made to the stands transformed by strip method. Results showed that the mixed stands at 16 years after transformation had an obvious layered structure and the species richness of understorey vegetation increased by 23.5%–52.9%. Soil enzyme activities of urease, phosphatase and sucrase increased by 6%–142%, 46%–99% and 31%–200%, respetively. Moreover, the transformed stands could effectively control the occurrence of pine caterpillars in plantations. Consequently the transformations enhanced the function of soil and water conservation. Keywords Pinus tabulaeformis - Monoculture - Transformation - Principles and methods - Assessment CLC number S791.254 - S727.22 Document code A Foundation item: This research was supported by grants from the Chinese Academy of Sciences (KZCX3-SW-418), National Natural Science Foundation of China (30100144), and National Key Technologies R & D Program of China (96-007-01-06).Biography: ZENG De-hui (1965-), male, Ph.D. professor in the Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, P. R. ChinaResponsible editor: Zhu Hong
基金Supported by"Twelfth Five-Year"National Scientific and Technological Support Project(2011BAD38B0602)~~
文摘[Objective] This study aimed to explore the relationship between different forest types and water conservation function. [Method] Based on field survey and experimental analysis, water conservation function of four typical forest stands in Jinyun Mountain of Chongqing was explored, including conifer-broadleaved mixed for- est, evergreen broad-leaved forest, bamboo forest and shrub forest. [Result] The re- sults showed that the order of saturated water storage capacity of soil in four forest stands was shrub forest (266.48 mm) 〉 conifer-broadleaved mixed forest (190.40 mm) 〉 evergreen broad-leaved forest (186.80 mm) 〉 bamboo forest (174.80 mm); the order of maximum water-holding capacity of litter was shrub forest (8.06 mm) 〉 conifer-broadleaved mixed forest (4.71 mm) 〉 evergreen broad-leaved forest (4.32 mm) 〉 bamboo forest (3.34 mm); the order of canopy interception in various forest stands was conifer-broadleaved mixed forest (16.15%) 〉 evergreen broad-leaved for- est (14.70%) 〉 bamboo forest (12.64%). [Conclusion] The study had great signifi- cance to rational manage forest resources, improve water environment and realize scientific management and use of water resources.
基金Supported by Science and Technology Foundation of Guizhou Province[Qiankehe-J(2009)No.2108)]Guizhou Normal University Fund for Doctor(2008)~~
文摘[Objective]The aim of this study was to select tartary buckwheat material with better health function.[Method]Used 35 kinds of tartary buckwheat as experimental materials,and the water holding capacity and expansion capacity had been determined.[Result] The water holding capacity of 35 kinds of tartary buckwheat will change in the range of 248.5%-341.4% with an average of 283.0%(the holding capacity of T324 was the highest),while the change of expansion capacity changed between 0.50 and 1.50 ml/g with an average of 1.05 ml/g(the expansion capacity of T463 was the highest).[Conclusion]This study had provided theoretical basis for screening better tartary buckwheat variety and its application.
基金Supported by Financial Innovation Ability Improving Engineering Project in Sichuan Province(2016TSCY-006)Technological Innovation Fund for Small and Medium Technology-based Enterprises of Nanchong City(15C0009)~~
文摘Rational development and utilization of hilly land is an effective measure for raising land productivity, developing countryside economy, increasing peasants' income, conserving soil and water, and improving eco-environment. The growth and root distribution of mulberry trees were studied. Various indexes including soil physical characters and hydrological status, water infiltration rate, water and soil loss and soil erosion amount were tested. The results indicated that mulberry trees had the effects of intercepting rainfall, improving soil infiltration rate, decreasing soil erosion amount, and conserving water and soil
基金Supported by the Twelfth Five-year-plan in National Science and Technology for the Rural Development in China(2011BAD31B01)~~
文摘Water and soil conservation is an important part of eco-civilization con-struction. It is a major part of eco-construction and lifeline of social and economy development. Therefore, water and soil conservation is of great significance in maintaining eco-safety. The research concluded status quo and characters of water and soil losses in China and analyzed water and soil conservation and construction of eco-civilization from the perspectives of water and soil conservation and con-struction of eco-civilization.
基金supported by National Natural Science Foundation of China (No 30872068)the Science and Technology Key Scientific Project of Heilongjiang Province (GA06B302-3)Fund of Thesis for Post Graduated Student of NEFU(GRAM09)
文摘A study was conducted to determine the characters of soil structure in different water and soil conservation forests in Keshan County,northwest of Heilongjiang Province,China.The soil bulk density,the ratio of non-capillary porosity and capillary porosity(NCP/CP),and the generalized soil structure index(GSSI) were measured for Fraxinus mandshurica,Larix gmelini,Pinus sylvestris var.mongolica,and Picea koraiensis plantations as well as the abandoned land(as control) adjacent to the forests in typical black soil region.Results show that at soil depth of 0–30cm,the soil bulk density of F.mandshurica forest and L.gmelini forest was lower than that of P.sylvestris var.mongolica forest and P.koraiensis forest,with the relative decrease of 8.04%–11.01%.The soil bulk density of L.gmelini forest was significantly different from that of the P.sylvestris var.mongolica forest and P.koraiensis forest.The NCP/CP values of the four types of plantations were all higher(59.75%–128.82% relatively) than that of abandoned land(p〈0.05),indicating that the soil aeration and permeability under forest were enhanced,especially under L.gmelini forest.GSSI values of the four types of forests were also relatively higher(2.98%–4.36%) than abandoned land(p〈0.05),indicating that those soil and water conservation forests,especially the F.mandshurica forest and P.koraiensis forest,can promote soil condition to approximate ideal soil structure.The result of this study can provide theoretical basis for scientifically evaluating the effects of vegetation restoration on soil quality in typical black soil region.
基金Supported by the Planning Subject of‘the Twelfth Five-year-plan’in National Scienceand Technology for the Rural Development in China(2011BAD31B01)~~
文摘With economy development,human destruction of eco-environment is deteriorating,which has become a key treatment nationwide.What's more,eco-environment construction is proceeding and multi-eco-environment projects are developing.Water and soil conservation and eco-environment construction should be a strategic task long-term insisted on,which is a part of agricultural construction.The research analyzed the relationship between water and soil conservation with eco-environment,concluded the process of ecological civilization construction in promoting water and soil conservation,and proposed countermeasures,laying foundation for water and soil conservation and ecological construction.
基金Supported by Project of National Science Foundation(41001321)Initial Funding of Doctor of Shenyang Normal University(2009102)~~
文摘The concept,merits and domestic project examples of ecological disposal technique of dispersal sewage were introduced in detail.It was pointed out that the ecological disposal of dispersal sewage was investment-saved,energy consumption-reduced and ecological balance-protected advanced technology.This technology was suitable for small community,dispersal units and agencies,villages and other regions without pipe network pervaded and an available approach for solving present environment-protection problems and keeping sustainable development in China.
基金Supported by Chinese Academy of Sciences-Knowledge Innovation Program Key Direction Project(KZCX2-YW-310)National Basic Research Program of China(2010CB951702)~~
文摘[Objective] This study was to provide theoretical basis for getting sustainable development of rural energy in Tibet into reality.[Method] By reviewing the rural energy resources in Tibet,we analyzed the characteristics and potential of rural biomass utilization in Tibet,and further put forward the sustainable countermeasures on the firewood substitution in Tibet.[Results] Renewable energies including hydraulic,geothermal,solar and wind resources are abundant in Tibet,while there is just a few of fossil energy resources such as oil and coal,with uneven distribution and poor exploration conditions.Traditional consumption of biomass energy resource accounts for a large proportion of the total energy consumption in Tibetan rural districts,which causes potential damage to the fragile ecological environment on the Tibetan Plateau.The excessive use of biomass energy destroyed the vegetation and evoked the environment deterioration such as the intensification of the water and soil loss and the declining of the soil fertility.[Conclusion] It is essential for Tibet to change its rural energy consumption structure,implement the Tibetan firewood alternative energy strategy and try to make full use of renewable energy such as solar energy,wind energy,hydro-energy instead of native vegetation and animal's droppings in order to reduce the adverse impacts of the irrational energy consumption on the ecological environment in Tibet.
基金Supported by the National Basic Research Program of China(2007CB407204)~~
文摘Ridge tillage, which is a very common and important tillage measure in the black soil area of northeast China, has some soil and water conservation bene- fits, but has little attention. It is very important to explore the spatial distribution of the ridge direction of the arable land and its soil and water conservation benefits in different terrain conditions in the black soil area. So Binxian County of Heilongjiang Province was selected as the study area, and 168 field investigation units were ex- tracted by stratified sampling method and investigated. According to equations of slope gradient factor and slope gradient in ridge direction, and based on the soft- ware of Arcmap, SPSS and Excel, the investigation data of soil and water loss in Binxian County were analyzed and counted, The results show that in plain, hilly and mountainous areas, the average ground slope gradients are 1.92°, 6.20° and 8.27° respectively, and the average slope gradients along ridge direction are 1.33°, 4.52°and 6.45° respectively, which account for about 70%, 73% and 78% of the average ground slope gradients in the same terrain condition; the relative quantities of soil erosion in the present ridge tillage condition account for about 55%, 69% and 67% respectively of that in down-slope ridge tillage conditions, so the present ridge tillage has obviously relative soil and water conservation benefits. Based on these results, the reasons of the present ridge tillage status were analyzed, and some reform measures were proposed. The results could not only help to comprehend the spatial distribution and soil and water conservation benefits of ridge tillage in the black soil area of Northeast China, but also provide scientific references for the layout of local soil and water conservation measures.
文摘The fiscal sustainability of China and the United States is of major concern globally. Based on comparative data analysis, this paper reveals that the government debt level of both countries is within the normal range. Robust growth prospects of both countries will also vigorously support their future mitigation of government debt level. Comparatively speaking, China's government debt level is healthy and, despite extensive concerns, even its local government debt is not very high. The assessment that China may encounter a crisis is not supported by evidence. Yet in the long run, both countries will face pressures from increased fiscal spending on elder care and healthcare stemming from an ageing population, which will threaten their fiscal sustainability. These challenges require both countries to speed up reforms of elder care and healthcare. Specifically, China needs to focus on elder care reforms and the US should attach more importance to healthcare reforms.
基金This paper was supported by the Environmental Protection Foundation of Jiangsu Province (2000(二) 0009) National Natural Science Foundation of China (NSFC39970605).
文摘Taihu Lake area is one of the most developed areas in agricultural production. Application of fertilizers and pesticides in large quantities greatly aggravate environmental pollution of this area, and water pollution has worsened to an unbearable condition. Two sampling farms (respectively 1 hm2) under rape-rice rotation and wheat-rice rotation were selected as studied ecosystem and a 5-yr-old Poplar forest and 8-yr-old Metasequoia forest were chosen in the selected areas. By collecting samples of Nitrogen, Phosphorus in water, crops and underground of forest, the transfer and loss of N and P (main water pollutants) in faming ecosystem were studied, and the effects of forest belts on non-point source pollution of agricultural lands was analyzed. The results indicated that the transfer and loss of N and P vary with means of rotation, types of crops and the amount of fertilizer application. Buffering forest belts betweens farmlands and ditches can effectively stop and purify such elements as N and P in soil runoffs, thus controlling non-point source pollution of agricultural lands. When the width ratio of farmland to forest belt is 100 to 40, 50.05% losing N, 29.37% losing P can be absorbed by forest under rape-rice rotation and 30.98% N, 86.73% P can be absorbed by forest under wheat-rice rotation. When the width ratio of farmland to forest belt is 150 to 40, 33.37% losing N, 19.58% losing P can be absorbed by the forest under rape-rice rotation, and under wheat-rice rotation 20.65% lost N and 57.82% lost P can be absorbed. There is only some purification effect when the width ration of farmland to forest belt is 200 to 40. Based on model of buffering forest belts, the width ratio of farmland to forest is determined between 100 to 40 and 150 to 40, because it not only can purify water, but also occupy less farmland. It is suggested that Poplars, with the characteristics of fast-growing and high value, are suitable to be planted as shelter-forest in Taihu Lake Watershed.
基金Supported by National Natural Science Foundation of China(41161037,31371582)~~
文摘[Objective] The paper was to study and modify non-limiting water range (NLWR) of soil. [Method] The water content when total soil water potential was -0.3 MPa or soil mechanical resistance was 0.85 MPa was selected as the lower limit of NLWR to replace the original water content of permanent wilting point or the water content under soil mechanical resistance of 2.0 MPa. NLWR could be calculated us-ing the minimum value of upper limit minus the maximum value of lower limit. [Re-sult] Compared with original NLWR or least limiting water range (LLWR), the modi-fied NLWR had more practical significance. When Db〉Db-thr, soil physical properties hindered the growth of crops, so the soil should be improved; when Db〉Db-thr, soil physical properties hindered the growth of crops, so-the soil should be improved; wtlen Db〈Db-thr, as long as the soil water content is within NLWR, soil physical properties had no effect on crop growth. NLWR at this time could be used as the basis for irrigation man- agement in farmland. [Conclusion] The study provides theoretical support and scientific basis for relevant researches about evolution rule and regulatory mechanisms of soil physical quality, relationship between soil physical quality and crop growth and yield, water-fertilizer-salt management of soil.
基金Supported by National Natural Science Foundation of China(31360358)Key Project of Yunnan Province(2015FA034)Yunnan Provincial Science and Technology Plan Benefiting the People(2014RA059)~~
文摘[Objective] This study aimed to investigate the effect of water stress on stay green of Yunge F2 generation. [Method] Total 26 sugarcane innovative germplasm materials of Yunge F2 generation, along with their female parent, were selected as the experimental materials. Based on the observation on appearance of stray green and other five physiological and biochemical indexes, the drought resis- tance of the experimental materials was evaluated comprehensively by subordinate function method, grey relational analysis, and cluster analysis. [Result] The rank of drought resistance of the experimental materials was not exactly the same between subordinate function method and grey relational analysis. However, the drought .re- sistance evaluation results by isometric range-based cluster analysis were consistent with those by the two foregoing methods except Yunge F2 11-68 and Yunge F1 11- 254. At the Euclidean distance of 2.00, the tested materials were classified into four groups. The first group included 8 drought-strongly resistant materials, the third group included 6 drought-moderately resistant materials, the fourth group included 3 drought-poorly resistant materials, and the second group included drought-strongly resistant and drought-moderately resistant materials. The drought resistance coeffi- cients of green leaf numberLtotal leaf number and top four leaves chlorophyll content showed significantly positive correlation with drought resistance comprehensive eval- uation value, thus green leaf number/total leaf number and top four leaves chloro- phyll content could be used as the evaluation indexes of drought resistance in sug- arcane. [Conclusion] The excellent materials possess strong drought resistance and good green holding performance, such as Yunge F2 11-159, can be used as crucial parents and basic germplasm materials in drought resistance breeding of sugarcane. 7
基金Supported by FAO of the United Nations under South-South Cooperation Program in Ethiopia(SSC/SPFS-FAO-ETHIOPIA-CHINA)~~
文摘[Objective] This comparative experiment was to explore the soil loss con- trol effects under cultivation combination of different soil and vegetation types, and to provide scientific basis for the upcoming pilot project of ecological recovery. [Method] Both the rudiment of water locomotion functioned by micro-landscape structures and different spatial combinations of various landscape constituents are considered, thus, the combination of multi-soil type, crop species and site conditions is designed in three different experimental sites. [Result] Soil loss estimates in experiments in South Wello significantly depended on various soil type, slope, vegetation and type of con- servation structure; grass cover tremendously reduces soil loss; legume cultivation performed better than cereal cultivation in soil loss control. [Conclusion] By conduct- ing the data analysis of the experiment, a scientific reference is proposed to the agri- culture planting and protective mode for the alleviation of water and soil loss in Amhara Region, Ethiopia.
文摘Remote sensing techniques and geographic information systems offer a good means of collecting and manipulating the data required for assessing conservation practices. A method for automatic generation of most of the data required by the Agricultural Non point Source erosion model is developed from three sources:(1) file with contour lines from the topographic maps(TM), (2) soil mapping units from the soil surveys, and (3)land cover from land sat TM image classification.