Twenty-five tree species indigenous to Guangdong Province were chosen in this study to portray their distribution patterns in relation to environmental factors. Both data of species distribution and environmental fact...Twenty-five tree species indigenous to Guangdong Province were chosen in this study to portray their distribution patterns in relation to environmental factors. Both data of species distribution and environmental factors were tabulated based on a digitized map of Guangdong Province gridded at 0.5° latitude × 0.5° longitude. Grid-based diversity was mapped using DMAP, a distribution mapping program, and horizontal patterns were assessed using Kruskal-Wallis tests. The diversity center of the indige- nous tree species under study is located north of 23° N. These tree species exhibit significant latitudinal variation (P = 0.007 4), but no significant longitudinal difference (P = 0.052 2). Non-metric Multidimensional Scaling (NMS) identified five different ecological species groups, while Canonical Correspondence Analysis (CCA) showed the distribution of tree species along each of the five envi- ronmental gradients. An understanding of the environmental correlates of distribution patterns has great implication for the introduc- tion of the indigenous tree species for afforestation.展开更多
Coal measure gas(also known as coal-bearing unconventional gas)is the key field and development direction of unconventional natural gas in recent years.The exploration and evaluation of coal measure gas(coalbed methan...Coal measure gas(also known as coal-bearing unconventional gas)is the key field and development direction of unconventional natural gas in recent years.The exploration and evaluation of coal measure gas(coalbed methane,coal shale gas and coal measure tight sandstone gas)from single coalbed methane has greatly expanded the field and space of resource evaluation,which is of positive significance for realizing the comprehensive utilization of coal resources,maximizing the benefits and promoting the innovation of oil and gas geological theory and technological advances in exploration and development.For the first time,in Yangmeishu Syncline of Western Guizhou Province,the public welfare coalbed methane geological survey project of China Geological Survey has been carried out a systematic geological survey of coal measure gas for the Upper Permian Longtan Formation,identified the geological conditions of coal measure gas and found high quality resources.The total geological resource quantity of coalbed methane and coal shale gas is 51.423×109 m3 and the geological resource abundance is up to 566×106 m3/km2.In this area,the coal measures are characterized by many layers of minable coal seams,large total thickness,thin to the medium thickness of the single layer,good gas-bearing property of coal seams and coal measure mudstone and sandstone,good reservoir physical property and high-pressure coefficient.According to the principle of combination of high quality and similarity of key parameters of the coal reservoir,the most favorable intervals are No.5-2,No.7 and No.13-2 coal seam in Well YMC1.And the pilot tests are carried out on coal seams and roof silty mudstone,such as staged perforation,increasing hydraulic fracturing scale and"three gas"production.The high and stable industrial gas flow with a daily gas output of more than 4000 m3 has been obtained,which has realized the breakthrough in the geological survey of coal measure gas in Southwest China.Based on the above investigation results,the geological characteristics of coal measure gas in the multi-thin-coal-seam-developed area and the coexploration and co-production methods,such as the optimization method of favorable intervals,the highefficiency fracturing and reservoir reconstruction method of coal measures,and the"three gas"drainage and production system,are systematically summarized in this paper.It will provide a reference for efficient exploration and development of coal measure gas in similar geological conditions in China.展开更多
On the basis of summarizing some literatures regarding research of agricultural production efficiency by using DEA at home,we conduct empirical analysis on agricultural production efficiency in 18 cities or counties o...On the basis of summarizing some literatures regarding research of agricultural production efficiency by using DEA at home,we conduct empirical analysis on agricultural production efficiency in 18 cities or counties of Hainan Province in the year 2002,2005 and 2008 by using DEA model.The results show that in 2005 Hainan Province suffered from unusual drought and windstorm,which made the effective value of agricultural production in all cities or counties relatively low;the regions with DEA effectiveness of agricultural production in the year 2002,2005 and 2008 were Qionghai City,Tunchang County,Lingao County,Danzhou City,Qiongzhong County and Baisha County.Haikou City,Wuzhishan City and Baoting County in the year 2002,Lingshui County in the year 2005,and Sanya City and Dongfang County in the year 2008 were also regions with DEA effectiveness,indicating that the input-output of these regions in the corresponding years is in optimal state.Finally,we conduct projection analysis on six cities and counties with non-DEA effectiveness in the year 2008 in Hainan Province,and based on this,find out the approach of improving agricultural production efficiency in these regions.展开更多
Control mode for typical karst rocky desertification in Guizhou Province,China is selected as the research object.The ecological benefit,the social and economic benefit and the popularization prospect of mode are sele...Control mode for typical karst rocky desertification in Guizhou Province,China is selected as the research object.The ecological benefit,the social and economic benefit and the popularization prospect of mode are selected as evaluation indices.Evaluation index system of control modebenefits for karst rocky desertification is established.The Dingtan mode and the Wangjiazhai-Yangchangdong small watershed control mode are se-lected as evaluation objects.Preliminary assessment on the two modes are carried out by Analytic Hierarchy Process,grading evaluation,and com-prehensive evaluation method.Result shows that comprehensive score of Dingtan mode is 3.81,which is higher than the score of Wangjiazhai-Yangchangdong small watershed control mode(3.11).In the aspects of ecological benefit and social and economic benefit,Dingtan mode(4.83and 3.258) is superior than the Wangjiazhai-Yangchangdong small watershed control mode(3.38 and 2.531).In the aspect of popularization pros-pect of mode,score of Dingtan mode(3) is lower than that of Wangjiazhai-Yangchangdong small watershed control mode(3.333).Therefore,theevaluation index system has certain science and offers reference and guidance for the karst rocky desertification control in southwest China.展开更多
基金Key Research Program of Guangdong Province (Grant No. 2002C20703) and Key Research Program of Guangdong Provincial Department ofForestry (Grant No. 2002-12)
文摘Twenty-five tree species indigenous to Guangdong Province were chosen in this study to portray their distribution patterns in relation to environmental factors. Both data of species distribution and environmental factors were tabulated based on a digitized map of Guangdong Province gridded at 0.5° latitude × 0.5° longitude. Grid-based diversity was mapped using DMAP, a distribution mapping program, and horizontal patterns were assessed using Kruskal-Wallis tests. The diversity center of the indige- nous tree species under study is located north of 23° N. These tree species exhibit significant latitudinal variation (P = 0.007 4), but no significant longitudinal difference (P = 0.052 2). Non-metric Multidimensional Scaling (NMS) identified five different ecological species groups, while Canonical Correspondence Analysis (CCA) showed the distribution of tree species along each of the five envi- ronmental gradients. An understanding of the environmental correlates of distribution patterns has great implication for the introduc- tion of the indigenous tree species for afforestation.
基金This study was supported by the China Geological Survey Projects(DD20160186,12120115008201)
文摘Coal measure gas(also known as coal-bearing unconventional gas)is the key field and development direction of unconventional natural gas in recent years.The exploration and evaluation of coal measure gas(coalbed methane,coal shale gas and coal measure tight sandstone gas)from single coalbed methane has greatly expanded the field and space of resource evaluation,which is of positive significance for realizing the comprehensive utilization of coal resources,maximizing the benefits and promoting the innovation of oil and gas geological theory and technological advances in exploration and development.For the first time,in Yangmeishu Syncline of Western Guizhou Province,the public welfare coalbed methane geological survey project of China Geological Survey has been carried out a systematic geological survey of coal measure gas for the Upper Permian Longtan Formation,identified the geological conditions of coal measure gas and found high quality resources.The total geological resource quantity of coalbed methane and coal shale gas is 51.423×109 m3 and the geological resource abundance is up to 566×106 m3/km2.In this area,the coal measures are characterized by many layers of minable coal seams,large total thickness,thin to the medium thickness of the single layer,good gas-bearing property of coal seams and coal measure mudstone and sandstone,good reservoir physical property and high-pressure coefficient.According to the principle of combination of high quality and similarity of key parameters of the coal reservoir,the most favorable intervals are No.5-2,No.7 and No.13-2 coal seam in Well YMC1.And the pilot tests are carried out on coal seams and roof silty mudstone,such as staged perforation,increasing hydraulic fracturing scale and"three gas"production.The high and stable industrial gas flow with a daily gas output of more than 4000 m3 has been obtained,which has realized the breakthrough in the geological survey of coal measure gas in Southwest China.Based on the above investigation results,the geological characteristics of coal measure gas in the multi-thin-coal-seam-developed area and the coexploration and co-production methods,such as the optimization method of favorable intervals,the highefficiency fracturing and reservoir reconstruction method of coal measures,and the"three gas"drainage and production system,are systematically summarized in this paper.It will provide a reference for efficient exploration and development of coal measure gas in similar geological conditions in China.
文摘On the basis of summarizing some literatures regarding research of agricultural production efficiency by using DEA at home,we conduct empirical analysis on agricultural production efficiency in 18 cities or counties of Hainan Province in the year 2002,2005 and 2008 by using DEA model.The results show that in 2005 Hainan Province suffered from unusual drought and windstorm,which made the effective value of agricultural production in all cities or counties relatively low;the regions with DEA effectiveness of agricultural production in the year 2002,2005 and 2008 were Qionghai City,Tunchang County,Lingao County,Danzhou City,Qiongzhong County and Baisha County.Haikou City,Wuzhishan City and Baoting County in the year 2002,Lingshui County in the year 2005,and Sanya City and Dongfang County in the year 2008 were also regions with DEA effectiveness,indicating that the input-output of these regions in the corresponding years is in optimal state.Finally,we conduct projection analysis on six cities and counties with non-DEA effectiveness in the year 2008 in Hainan Province,and based on this,find out the approach of improving agricultural production efficiency in these regions.
基金Supported by the Special Project for High-level Talents of Guizhou Province (TZJF-2008.No.22)
文摘Control mode for typical karst rocky desertification in Guizhou Province,China is selected as the research object.The ecological benefit,the social and economic benefit and the popularization prospect of mode are selected as evaluation indices.Evaluation index system of control modebenefits for karst rocky desertification is established.The Dingtan mode and the Wangjiazhai-Yangchangdong small watershed control mode are se-lected as evaluation objects.Preliminary assessment on the two modes are carried out by Analytic Hierarchy Process,grading evaluation,and com-prehensive evaluation method.Result shows that comprehensive score of Dingtan mode is 3.81,which is higher than the score of Wangjiazhai-Yangchangdong small watershed control mode(3.11).In the aspects of ecological benefit and social and economic benefit,Dingtan mode(4.83and 3.258) is superior than the Wangjiazhai-Yangchangdong small watershed control mode(3.38 and 2.531).In the aspect of popularization pros-pect of mode,score of Dingtan mode(3) is lower than that of Wangjiazhai-Yangchangdong small watershed control mode(3.333).Therefore,theevaluation index system has certain science and offers reference and guidance for the karst rocky desertification control in southwest China.
