The aim was to further research soil erosion characteristics and accurately predict soil erosion amount in karst areas. Based on field surveys and research achievements available, yellow soils, which are widely distri...The aim was to further research soil erosion characteristics and accurately predict soil erosion amount in karst areas. Based on field surveys and research achievements available, yellow soils, which are widely distributed, were chosen as test soil samples and slope, rain intensity, vegetation coverage and bare-rock ratio were taken as soil erosion factors. Artificial rain simulation instruments （needle-type） were made use of to simulate correlation of rain intensity, vegetation coverage, and bare-rock ratio with soil erosion quantity. Furthermore, multiple-factor linear regression analysis, stepwise regression analysis and multiple-factor non-linear regression analy- sis were made to establish a multiple-factor formula of soil erosion modulus with dif- ferent slopes and select regression models with high correlation coefficients. The re- sults show that a non-linear regression model reached extremely significant level or significant level （0.692〈FF〈0.988） and linear regression model achieved significant lev- el （0.523〈FF〈0.634）. The effects of erosion modulus changed from decreasing to in- creasing and the erosion factors from high to low were rain intensity, vegetation cov- erage and bare-rock ratio when slope gradient was at 6~, 16~, 26~ and 36~. The mod- el is of high accuracy for predicting gentle slope and abtupt slope, which reveals correlation of erosion modulus with erosion factors in karst areas.展开更多
China is a mountainous country,and Southwest mountain areas cover the most mountain areas in China and have the most serious problems.Taking Zhaotong city as the study area,based on 902 rural household questionnaires ...China is a mountainous country,and Southwest mountain areas cover the most mountain areas in China and have the most serious problems.Taking Zhaotong city as the study area,based on 902 rural household questionnaires of 11 villages in 2 counties and Tobit model,this paper analyzes the geographical differences and influencing factors of energy consumption for non-production purposes of rural households living in different terrain conditions.This research finds that:(1) Coal takes up the main part of energy consumption in valley areas and coal consumption is mainly affected by per capita cultivated land area,household income,proportion of rural household energy expenditure in total expenditure,coal price,and family population size.Firewood takes up the main part of energy consumption in high mountain areas and firewood consumption is mainly affected by per capita firewood forest area,distance to purchase coal,household income,electricity price,and coal price.(2) Only when the distance is greater than 20 kilometers,that is the average distance of rural households living in middle mountain areas(1,600m^1,800m) to purchase coal,the transportation condition has a significant impact on coal consumption.(3) In high mountain areas,prices of coal and electricity are the main factors influencing energy consumption choice of rural households.Too high prices of coal and electricity would to some extent lead rural households to choose firewood as the main energy consumption type.Compared to coal,rural households prefer to choose electricity.展开更多
Characteristics and distributions of humic acid(HA) and soil organic matter(SOM) in a yellow soil profile and a limestone soil profile of the southwest China Karst area were systematically investigated to reveal their...Characteristics and distributions of humic acid(HA) and soil organic matter(SOM) in a yellow soil profile and a limestone soil profile of the southwest China Karst area were systematically investigated to reveal their evolutions in different soils of the study area. The results showed that characteristics and distribution of SOM along the two soil profiles were notably different. Total organic carbon(TOC) contents of soil samples decreased just slightly along the limestone soil profile but sharply along the yellow soil profile. TOCs of the limestone soils were significantly higher than those of the corresponding yellow soils, and C/N ratios of SOMs showed a similar variation trend to that of TOCs, indicating that SOM can be better conserved in the limestone soil than in the yellow soil. The soil humic acids were exhaustively extracted and further fractionated according to their apparent molecular weights using ultrafiltration techniques to explore underlying conservation mechanisms. The result showed that C/N ratios of HAs from different limestone soil layers were relatively stable and that large molecular HA fractions predominated the bulk HA of the top soil, indicating that HA in the limestone profile was protected while bio and chemical degradations were retarded. Combined with organic elements contents and mineral contents of two soils, weconcluded that high calcium contents in limestone soils may play a key role in SOM conservation by forming complexation compounds with HAs or/and enclosing SOMs with hypergene CaCO_3 precipitation.展开更多
Guiyang is a famous tourist city located in southwestern China. In this study, dust from eleven residential areas, seven city squares, and nine schools was collected to measure the heavy metal levels and evaluate its ...Guiyang is a famous tourist city located in southwestern China. In this study, dust from eleven residential areas, seven city squares, and nine schools was collected to measure the heavy metal levels and evaluate its risk. At each sampling site, 4–5 sub-samples were taken as a bulk sample. All samples were air-dried, ground, passed through a 0.105 mm nylon sieve, digested with HNO3-HClO4 to determine the concentrations of Cd, Cu, Ni, Pb and Zn by ICP-MS, and digested with 1:1 aqua regia to determine As by AFS. The results show that the concentrations of As, Cd, Cu, Ni, Pb and Zn in dust of Guiyang City follow normal distribution with means of 16.1, 1.54, 138, 47.7, 129 and 479 mg/kg, respectively. Levels of As, Cd, Cu, Ni, Pb and Zn exceed the background level of soil in Guizhou Province by 33%, 96%, 100%, 78%, 96%, and 100%, respectively. Cd, Cu, Pb and Zn are heavily accumulated in dust of living areas with accumulation factors of 4.10, 5.12, 4.12 and 5.51, respectively. City square possesses the highest geometric means of As, Cd, Cu, Pb, and Zn. The risks of heavy metal exposure to teenagers are not obvious and in an order of As>Pb>Cu>Ni>Zn(Cd).展开更多
The formation of the ancient town of Heijing conforms to the natural conditions and local conditions,and makes effective use of the natural mountains,water bodies,trees and other resources of the ancient town,so that ...The formation of the ancient town of Heijing conforms to the natural conditions and local conditions,and makes effective use of the natural mountains,water bodies,trees and other resources of the ancient town,so that the ancient town and nature rely on each other and unify harmoniously.Through the analysis of the environmental characteristics of the ancient town,this paper further explores its cultural connotation.展开更多
Employment of people with disabilities in Southwest China’s ethnic minority areas is characterized by relatively high pressure, a poor environment and single form. Supported employment can solve the problems faced by...Employment of people with disabilities in Southwest China’s ethnic minority areas is characterized by relatively high pressure, a poor environment and single form. Supported employment can solve the problems faced by people with disabilities in the ethnic minority areas of Southwest China. Therefore, it is of practical significance to promote such a new form of employment. But in promoting the development of supported employment, it is necessary to strengthen its local top-level design and to establish corresponding legal and policy systems so as to give full play to the positive role of the government and establish a strong support system.展开更多
The serious degradation of the ecological environment and the rapid expansion of stone desert have had a serious effect on the economic development of karst and rock-naked mountain areas in Southwest China. Moreover, ...The serious degradation of the ecological environment and the rapid expansion of stone desert have had a serious effect on the economic development of karst and rock-naked mountain areas in Southwest China. Moreover, these areas are still at the initial stage of industrialization, characterized by a greater significance of agriculture to the economy, face sharp contradictions among the population, the arable land and resources, and are suffering because of a shortage of investment. On the basis of this current situation, three recommendations are made in this article: "coordinating the relations among grain, ecology, population and economic development", "increasing the input of science and technology", and "adopting policies consistent with social equity in areas of poverty".展开更多
基金Supported by National Science and Technology Support Program in Twelfth Five-year Plan(2012BAD05B06)Special Funds for Excellent Young Scientific Talents in Guizhou[(2011)14]~~
文摘The aim was to further research soil erosion characteristics and accurately predict soil erosion amount in karst areas. Based on field surveys and research achievements available, yellow soils, which are widely distributed, were chosen as test soil samples and slope, rain intensity, vegetation coverage and bare-rock ratio were taken as soil erosion factors. Artificial rain simulation instruments （needle-type） were made use of to simulate correlation of rain intensity, vegetation coverage, and bare-rock ratio with soil erosion quantity. Furthermore, multiple-factor linear regression analysis, stepwise regression analysis and multiple-factor non-linear regression analy- sis were made to establish a multiple-factor formula of soil erosion modulus with dif- ferent slopes and select regression models with high correlation coefficients. The re- sults show that a non-linear regression model reached extremely significant level or significant level （0.692〈FF〈0.988） and linear regression model achieved significant lev- el （0.523〈FF〈0.634）. The effects of erosion modulus changed from decreasing to in- creasing and the erosion factors from high to low were rain intensity, vegetation cov- erage and bare-rock ratio when slope gradient was at 6~, 16~, 26~ and 36~. The mod- el is of high accuracy for predicting gentle slope and abtupt slope, which reveals correlation of erosion modulus with erosion factors in karst areas.
基金support provided by National Natural Sciences Foundation of China (No. 41271146)National Key Technology R&D Program (No. 2008BAH31B01)
文摘China is a mountainous country,and Southwest mountain areas cover the most mountain areas in China and have the most serious problems.Taking Zhaotong city as the study area,based on 902 rural household questionnaires of 11 villages in 2 counties and Tobit model,this paper analyzes the geographical differences and influencing factors of energy consumption for non-production purposes of rural households living in different terrain conditions.This research finds that:(1) Coal takes up the main part of energy consumption in valley areas and coal consumption is mainly affected by per capita cultivated land area,household income,proportion of rural household energy expenditure in total expenditure,coal price,and family population size.Firewood takes up the main part of energy consumption in high mountain areas and firewood consumption is mainly affected by per capita firewood forest area,distance to purchase coal,household income,electricity price,and coal price.(2) Only when the distance is greater than 20 kilometers,that is the average distance of rural households living in middle mountain areas(1,600m^1,800m) to purchase coal,the transportation condition has a significant impact on coal consumption.(3) In high mountain areas,prices of coal and electricity are the main factors influencing energy consumption choice of rural households.Too high prices of coal and electricity would to some extent lead rural households to choose firewood as the main energy consumption type.Compared to coal,rural households prefer to choose electricity.
基金financial supports are from the National Major Research Program of China (2013CB956702)the Natural Science Foundation of China (41273149, 41173129)+2 种基金the Science Foundation of Guizhou (20113109)the 100-Talent Program of CASthe opening project from the state key laboratory of environmental geochemistry
文摘Characteristics and distributions of humic acid(HA) and soil organic matter(SOM) in a yellow soil profile and a limestone soil profile of the southwest China Karst area were systematically investigated to reveal their evolutions in different soils of the study area. The results showed that characteristics and distribution of SOM along the two soil profiles were notably different. Total organic carbon(TOC) contents of soil samples decreased just slightly along the limestone soil profile but sharply along the yellow soil profile. TOCs of the limestone soils were significantly higher than those of the corresponding yellow soils, and C/N ratios of SOMs showed a similar variation trend to that of TOCs, indicating that SOM can be better conserved in the limestone soil than in the yellow soil. The soil humic acids were exhaustively extracted and further fractionated according to their apparent molecular weights using ultrafiltration techniques to explore underlying conservation mechanisms. The result showed that C/N ratios of HAs from different limestone soil layers were relatively stable and that large molecular HA fractions predominated the bulk HA of the top soil, indicating that HA in the limestone profile was protected while bio and chemical degradations were retarded. Combined with organic elements contents and mineral contents of two soils, weconcluded that high calcium contents in limestone soils may play a key role in SOM conservation by forming complexation compounds with HAs or/and enclosing SOMs with hypergene CaCO_3 precipitation.
基金supported by National Natural Science Foundation of China(41161079)
文摘Guiyang is a famous tourist city located in southwestern China. In this study, dust from eleven residential areas, seven city squares, and nine schools was collected to measure the heavy metal levels and evaluate its risk. At each sampling site, 4–5 sub-samples were taken as a bulk sample. All samples were air-dried, ground, passed through a 0.105 mm nylon sieve, digested with HNO3-HClO4 to determine the concentrations of Cd, Cu, Ni, Pb and Zn by ICP-MS, and digested with 1:1 aqua regia to determine As by AFS. The results show that the concentrations of As, Cd, Cu, Ni, Pb and Zn in dust of Guiyang City follow normal distribution with means of 16.1, 1.54, 138, 47.7, 129 and 479 mg/kg, respectively. Levels of As, Cd, Cu, Ni, Pb and Zn exceed the background level of soil in Guizhou Province by 33%, 96%, 100%, 78%, 96%, and 100%, respectively. Cd, Cu, Pb and Zn are heavily accumulated in dust of living areas with accumulation factors of 4.10, 5.12, 4.12 and 5.51, respectively. City square possesses the highest geometric means of As, Cd, Cu, Pb, and Zn. The risks of heavy metal exposure to teenagers are not obvious and in an order of As>Pb>Cu>Ni>Zn(Cd).
文摘The formation of the ancient town of Heijing conforms to the natural conditions and local conditions,and makes effective use of the natural mountains,water bodies,trees and other resources of the ancient town,so that the ancient town and nature rely on each other and unify harmoniously.Through the analysis of the environmental characteristics of the ancient town,this paper further explores its cultural connotation.
文摘Employment of people with disabilities in Southwest China’s ethnic minority areas is characterized by relatively high pressure, a poor environment and single form. Supported employment can solve the problems faced by people with disabilities in the ethnic minority areas of Southwest China. Therefore, it is of practical significance to promote such a new form of employment. But in promoting the development of supported employment, it is necessary to strengthen its local top-level design and to establish corresponding legal and policy systems so as to give full play to the positive role of the government and establish a strong support system.
文摘The serious degradation of the ecological environment and the rapid expansion of stone desert have had a serious effect on the economic development of karst and rock-naked mountain areas in Southwest China. Moreover, these areas are still at the initial stage of industrialization, characterized by a greater significance of agriculture to the economy, face sharp contradictions among the population, the arable land and resources, and are suffering because of a shortage of investment. On the basis of this current situation, three recommendations are made in this article: "coordinating the relations among grain, ecology, population and economic development", "increasing the input of science and technology", and "adopting policies consistent with social equity in areas of poverty".
