The precipitation distribution quantity of canopy in broadleaved/Korean pine forest was measured during the growing season (Jun.–Sept.) in 2001 in the Changbai Mountain, Jilin Province, P. R. China. Results indicated...The precipitation distribution quantity of canopy in broadleaved/Korean pine forest was measured during the growing season (Jun.–Sept.) in 2001 in the Changbai Mountain, Jilin Province, P. R. China. Results indicated that the amounts of stemflow, throughfall, and interception were 37.39, 322.12 and 109.69 mm, accounting for 7.97%, 68.65% and 23.38% of the total rainfall, respectively. The rate of stemflow was higher in Jul. and Aug. than other months. The rate of throughfall dropped off from Jun. to Sept., however, rate of interception changed contrarily from 19.43% to 31.02% during the growing season. According to our analysis, the concentration of nutrient elements were arranged as Ca>Mg>N>K>Fe>P>Cu>Mn for rainfall, K>N>Mg>Ca>P>Fe>Mn>Cu for throughfall, and Mn>P>K>Cu>Fe>N>Mg>Ca for being leached through canopy. Nutrients concentration in stewflow and throughfall changed significantly when rainfall passed canopy, and concentration of all elements increased except for Ca and Mg.展开更多
The physical properties of soil on two hill slopes of 35% and 55% in orange orchard cultivated by the Mro tribe of Chittagong Hill Tracts (CHTs) were evaluated and compared with those of bushy hill forests. Soil sam...The physical properties of soil on two hill slopes of 35% and 55% in orange orchard cultivated by the Mro tribe of Chittagong Hill Tracts (CHTs) were evaluated and compared with those of bushy hill forests. Soil samples were collected from three different depths (0-5 cm, 5-15 cm and 15-30 cm), digging three profiles in each land use for determining moisture content, organic matter content and particle density. Maximum water holding capacity, field capacity, dry and moist bulk density and porosity were determined only for the surface soils. Moisture content at all the soil depths was significantly higher (p≤ 0.05) in orange orchard than in forest on both the slopes. Orange orchard contained lower mean soil organic matter than forest on 55% slope, while it contained higher values on 35% slope compared to forest. The highest value of the above two properties was found at surface soil in both the land uses on both the slopes, decreasing with the increase of soil depth. On both the slopes maximum water holding capacity and porosity of surface soil and particle density at all soil depths were lower in orange orchard compared to those in forest. Field capacity values of surface soil did not show consistency in trend for the differences between the two land uses on both the slopes. Bulk density value of moist and dry surface soil was higher in orange orchard than in forest on both the hill slopes.展开更多
Landslides are natural disasters which can pose a serious threat to human and property in many areas around the world. The Transient Rainfall Infiltration and Grid-based Regional Slope-stability (TRIGRS) model was use...Landslides are natural disasters which can pose a serious threat to human and property in many areas around the world. The Transient Rainfall Infiltration and Grid-based Regional Slope-stability (TRIGRS) model was used to investigate the rainfall-induced shallow landslides in a forested mountain region, Korea. Various input data for TRIGRS model include time-varying rainfall, topographic characteristics, soil depth, material strength, and hydraulic properties. A series of calculations were conducted in determining the slope stability over the Jangheung region in Korea during the storm occurred on August 6, 1998. The results show that TRIGRS model captured about 64.1% of landslides that were extracted from the IKONOS2 imageries. The model demonstrated how the factor of safety changed with time during a storm considering both the transient and spatial responses of pore water pressure in its slope stability calculation.展开更多
Bird communities were surveyed in natural deciduous forest of both slope area and valley area at Mt. Gyebangsan (3740 30 N, 12830 1 E), Gangwon Province, South Korea in winter, spring, summer and autumn from September...Bird communities were surveyed in natural deciduous forest of both slope area and valley area at Mt. Gyebangsan (3740 30 N, 12830 1 E), Gangwon Province, South Korea in winter, spring, summer and autumn from September 2000 to November 2001. The investigating results showed that there existed differences in the bird species composition, richness, bird species diversity, guild structure between slope area and valley area, and the vertical forest structure, especially coverage of understory, and diameter at breast height (DBH) distribution also had significant difference between the two study areas. The differences in habitat structure between the areas are very likely to have influences on how birds used the available habitat.展开更多
The present study was undertaken in seven natural forest types of temperate zone (1500 to 3100 m, a.s.l.) of Garhwal Himalaya to understand the effects of slope aspects viz., north-east (NE), north-west (NW), so...The present study was undertaken in seven natural forest types of temperate zone (1500 to 3100 m, a.s.l.) of Garhwal Himalaya to understand the effects of slope aspects viz., north-east (NE), north-west (NW), south-east (SE) and south-west (SW), on the forest structure, composition and soil characteristics of each selected forest type. The sample plots in each forest type were laid out by using stratified random approach. The indices i.e., the Importance Value Index, Shannon-Wiener diversity index, Simpson’s concentration of Dominance, Simpson diver-sity index, Pielou equitability and Margalef species richness index were calculated statistically using standard softwares to elucidate the differ-ences in forest structure and composition of forest types on different slope aspects of the sites. The composite soil samples were taken from each forest stand and the physico-chemical properties of the soil i.e., moisture content (MC), water holding capacity (WHC), pH, organic carbon (OC), phosphorus (P), potassium (K) and available nitrogen (N) were analyzed. The results show that the higher values of total basal cover (74.4 m2·ha-1 in Quercus semecarpifolia forest), Concentration of dominance (0.85 in Pinus roxburghii forest) and Tree diversity (1.81 in Quercus floribunda forest) in the forests were recorded in the northern aspects. MC (40.8% in Quercus leucotrichophora forest), WHC (48.9% in Cupressus torulosa forest), OC (3.8% in Cedrus deodara forest), P (31.9 kg·ha-1 in Quercus leucotrichophora forest) and N (1.0% in Pinus roxburghii forest) had also higher values in the soils of northern aspects. Consequently the higher productivity of the forests was also noticed on the northern aspects.展开更多
This study uses DEM (Digital Elevation Model) data and remote sensing maps of the study area in 1993, 1999, and 2009 to analyze the slope gradient change of land use patterns in Qiandongnan Prefecture, Guizhou provi...This study uses DEM (Digital Elevation Model) data and remote sensing maps of the study area in 1993, 1999, and 2009 to analyze the slope gradient change of land use patterns in Qiandongnan Prefecture, Guizhou province, China. The land use data were classified into five types, forest, farmland, grassland, water and built-up, the slope gradients were divided into four grades. Indices for analyzing land use features were defined by their proportions, transformation matrixes, land use degree and changes The results showed that all land use types can be found at every gradient. Generally, with the slope degree increased, the area of forest being augmented as well, while the area of the other land use types (farmland, grassland and build-up) declined. Moreover, a mass of farmland were shifted from other land use types from o° to 25°, while a quantity of forest were transformed from the other land use types on 〉 25° from 2993 to 2009. In terms of land use degree and changes, the area of farmland and buildup land use types decreased when slope degree increased. Finally, we calculated the five landscape pattern metrics: Patch Density (PD) value, Largest Patch Index (LPI), Shannon's Diversity Index (SHDI), Area-Weighted Mean Shape Index (AWMSI) and Contagion Index (CONTAG). The results of metricsanalysis showed that PD values, SHDI values and CONTA values had a similar variation trend, that is, they decreased when slope degree increased. There was no obvious variation trend on LPI value.展开更多
Status of organic carbon (C), total nitrogen (N), available potassium (K), calcium (Ca) and phosphorus (P) in three different depths (0-5 cm, 5-15 cm and 15?30 cm) on two hill slopes of 35% and 55% in orange orchard c...Status of organic carbon (C), total nitrogen (N), available potassium (K), calcium (Ca) and phosphorus (P) in three different depths (0-5 cm, 5-15 cm and 15?30 cm) on two hill slopes of 35% and 55% in orange orchard cultivated by the Mro tribe of Chittagong Hill Tracts (CHTs) were evaluated and compared with those in degraded bush forests, through digging three profiles in each land use. The content of all the five nutrients was found to be higher in the soil of orange orchard than in the soil of forest. But the variation was not consistent for both the slopes. The content varied depth wise also, having the highest value in surface soil in case of both the land uses on both the slopes. A mean available K content was significantly higher in orange orchard than in forest on 55% slope, while it was lower on 35% slope. Surface soil contained the nutrients of K and Ca with the amount of 0.2905-mg·g^(-1) soil and 3.025-mg·g^(-1)soil respectively in the orchard, while 0.1934-mg·g^(-1) soil and 1.6083-mg·g^(-1) soil were respectively in the forest. Organic carbon and total nitrogen were found more or less similar in surface soil on both the land uses showing a slight difference. Available P was found only in orange orchard, and in forest it was too little in amount to detect by the spectrophotometer. The degraded forests were poor in nutrient content due to high rate of soil erosion, which would be possible to be improved by bringing it under tree cover as proved by the adaptation of orange orchard there.展开更多
Soil erosion in hilly areas of the Sichuan Basin is a serious concern over sustainable crop production and sound ecosystem. A 3-year experiment was conducted using the method of runoff plots to examine the effects of ...Soil erosion in hilly areas of the Sichuan Basin is a serious concern over sustainable crop production and sound ecosystem. A 3-year experiment was conducted using the method of runoff plots to examine the effects of terracing and agroforestry in farmland systems on soil and water conservation of slope fields in the hilly areas in Jianyang County, Sichuan Province, Southwestern China. A power function (Y = aXb) can statistically describe the relationship between water runoff (Y) and rainfall (X). The regression equation for the treatment of sloping terraces with crops (Plot 2) is remarkably different from that for the treatment of sloping terraces with grasses and trees (Plot 1) and the conventional up- and down-slope crop system (Plot 3) regarding equation coefficients, while regression equations are similar between Plot 1 and Plot 3. Water runoff amount and runoff coefficient of slope fields increased by 21.5~41.0 % and 27.5~69.7 % respectively, compared to those of sloping terraces, suggesting that terracing notably reduced the water runoff in the field. In the case of sloping terraces, lower amount of water runoff was observed on sloping terraces with crops than on sloping terraces with grasses and trees. Sediment yields on the slope fields in the normal year of rainfall distribution were notably higher (34.41~331.67 % and 37.06~403.44 % for Plot 1 and Plot 2, respectively) than those on sloping terraces, implying that terracing also plays a significant role in the reduction in soil erosion. It is suggested that terracing with crops is significantly effective for soil and water conservation in cultivatedfarmland, while the conventional practice of up- and down- slope cultivation creates high rates of water runoff and soil sediment transport. Terracing with grasses and fruit trees shows a less reduction in water runoff than terracing with crops, which was observed in the 3-year experiments.展开更多
A study was conducted to investigate the effects of skid trail slope and traffic levels on soil disturbances at two soil depths (0--10 and 10-20 cm). The treatments were set at four traffic levels (2, 7, 12 and 20...A study was conducted to investigate the effects of skid trail slope and traffic levels on soil disturbances at two soil depths (0--10 and 10-20 cm). The treatments were set at four traffic levels (2, 7, 12 and 20) two slope classes (〈20% and 〉20%) and two soil depths (0-10 and 10-20 cm). Results show that skidder traffic, longitudinal slope and soil depth have significant effect on soil bulk density in skid trail. Compari- son of average soil bulk density in different traffic levels shows that there are significant differences in average bulk density between different traffic levels and control (p〈0.05). The average bulk densities in different slopes and soil depths are significantly increased with increase in traffic levels, maximized at 12 passes (p〈0.05), but there are no significant differences between 12 and 20 passes. The interaction effects between traffic and soil depth are significant (F005,3=0.109, p〈0.001). For all traffic treatments, there are significant differences in soil moisture con- tent between the two slope classes and the two depths (p〈0.001). However, the interaction effects between traffic levels and slope classes are not significant (p 〉0.05), although skidder traffic and slope affected soil moisture content.展开更多
This work was completed on the study of the southern slope scrublands (matorrals) of Tlemcen region in the northwest of Algeria (Western Algeria). These scrublands are under various states of degradation, made up ...This work was completed on the study of the southern slope scrublands (matorrals) of Tlemcen region in the northwest of Algeria (Western Algeria). These scrublands are under various states of degradation, made up of Quercus ilex, Juniperus oxycedrus, Thymus ciliatus, Rosmarinus officinalis. The problems sought in this study are to give the actual position of vegetable cover and in particular that of the formations to matorrals currently existing in the southern slope of the area of Tlemcen, while being based on the phytoecological aspect of the vegetable groupings which constitute this inheritance. Sampling is the first phase of work based on the analysis of the spatial variations of the structure and composition floristic and considering the nature of the problem to be treated, the authors considered to be useful to use the method Zuricho Montpeli6raine developed at the point by Braun-Blanquet, the method usually used consists to collect all the plant species and to make the list of the species on a small square of surface 100 m2 (have it minimal). The floristic readings (150 on the whole) were taken according to the method of Braun-Blanquet. Our results show that there exists a therophytisation marked by a general invasion of annual species as show us as the synergistic action of the aridity and the anthropic action generated important modifications on the level of the vegetation in the dynamic direction. This advanced degradation leads a steppisation which results in a substitution of the elements of the matorrals by species more adapted much the xericity.展开更多
The paper gives two examples of larger construction projects with typical stability problems. The first example is from Sakhalin Island in the Russian Far East. It is connected with a construction of oil and gas pipel...The paper gives two examples of larger construction projects with typical stability problems. The first example is from Sakhalin Island in the Russian Far East. It is connected with a construction of oil and gas pipelines through the mountainous terrain in Makarov region. The region has an active geotectonic history and is highly affected by uncontrolled erosion and extensive landslips. Basic principles of landslide hazard mitigation are presented. The second example is from a motorway construction in Azerbaijan. This motorway leads from Baku to Russia through a seismo-tectonically active area at the toe of Caucasian mountains and in some places is situated in deep cuts at the toe of high slopes. This unsuitable routing, together with seismic activity, led to a slope stability failure of a slope affected by recent tectonic movements near the village of Devechi. Stability conditions and designed remedy measures are presented.展开更多
The effects of slope aspects on soil biogeochemical properties and plant communities in forested environments have been studied extensively; however, slope aspect influence on soil microbial communities remains largel...The effects of slope aspects on soil biogeochemical properties and plant communities in forested environments have been studied extensively; however, slope aspect influence on soil microbial communities remains largely unexamined, despite the central role of soil biota in ecosystem functioning. In this study, the communities of both soil bacteria and arbuscular mycorrhizal fungi (AMF) were investigated using tagged pyrosequencing for three types of slope aspects (south-facing aspect, north-facing aspect and flat area) in a boreal forest of the Greater Khingan Mountains, China. The bacterial and AMF community composition differed with slope aspects. Bacterial diversity was the lowest on the north-facing aspect, and AMF diversity was the lowest on the flat area. Aspects also had a significant impact on soil pH and available phosphorus (P) and shrubby biomass. Soil pH and understory shrub biomass were significantly correlated with bacterial communities, and soil available P and shrub biomass showed significant correlations with AMF communities. Our results suggested that slope aspects affected bacterial and AMF communities, mediated by aspect-induced changes in plant community and soil chemical properties (e.g., pH and available P), which improved the knowledge on the effects of forest slope aspects on aboveground and belowground communities.展开更多
Green infrastructure is classic public goods which can be utilized by everybody simultaneously atany time of the day. Green infrastructure which is the interconnected system of green spaces that conservesnatural ecosy...Green infrastructure is classic public goods which can be utilized by everybody simultaneously atany time of the day. Green infrastructure which is the interconnected system of green spaces that conservesnatural ecosystem values and functions, sustains clean air and water, not only provide a pleasant and naturalenvironment but also contribute to improving quality of life in urban areas. In other words green infrastructureis the communitys natural life support system and the ecological framework needed for environmental andeconomic sustainability in urban areas. Within this context, this paper offers an overview of green infrastructuredevelopment in Malaysia, its status, constraint, potential and future directions. The case study of KualaLumpur city, which is one of the fastest growing cities in the country, highlights the scenario of urban areasdevelopment in Malaysia. This includes the role played by the government agencies and non-governmentorganizations in developing and promoting forest areas as public parks. The provisions of recreational andeducational facilities in the parks as well as the protection measures of the resources undertaken by relevantauthorities are also discussed. This paper also highlights the response of the public to the opportunities beingprovided in these areas for recreation and education purposes.展开更多
基金This paper was supported by Chinese Academy of Science (KZCX2-406) Institute of Applied Ecology (SCXZD0101)+1 种基金 Chinese Academy of Science Shenyang and the Open Research Station of Changbai Mountain Forest Ecosystem.
文摘The precipitation distribution quantity of canopy in broadleaved/Korean pine forest was measured during the growing season (Jun.–Sept.) in 2001 in the Changbai Mountain, Jilin Province, P. R. China. Results indicated that the amounts of stemflow, throughfall, and interception were 37.39, 322.12 and 109.69 mm, accounting for 7.97%, 68.65% and 23.38% of the total rainfall, respectively. The rate of stemflow was higher in Jul. and Aug. than other months. The rate of throughfall dropped off from Jun. to Sept., however, rate of interception changed contrarily from 19.43% to 31.02% during the growing season. According to our analysis, the concentration of nutrient elements were arranged as Ca>Mg>N>K>Fe>P>Cu>Mn for rainfall, K>N>Mg>Ca>P>Fe>Mn>Cu for throughfall, and Mn>P>K>Cu>Fe>N>Mg>Ca for being leached through canopy. Nutrients concentration in stewflow and throughfall changed significantly when rainfall passed canopy, and concentration of all elements increased except for Ca and Mg.
文摘The physical properties of soil on two hill slopes of 35% and 55% in orange orchard cultivated by the Mro tribe of Chittagong Hill Tracts (CHTs) were evaluated and compared with those of bushy hill forests. Soil samples were collected from three different depths (0-5 cm, 5-15 cm and 15-30 cm), digging three profiles in each land use for determining moisture content, organic matter content and particle density. Maximum water holding capacity, field capacity, dry and moist bulk density and porosity were determined only for the surface soils. Moisture content at all the soil depths was significantly higher (p≤ 0.05) in orange orchard than in forest on both the slopes. Orange orchard contained lower mean soil organic matter than forest on 55% slope, while it contained higher values on 35% slope compared to forest. The highest value of the above two properties was found at surface soil in both the land uses on both the slopes, decreasing with the increase of soil depth. On both the slopes maximum water holding capacity and porosity of surface soil and particle density at all soil depths were lower in orange orchard compared to those in forest. Field capacity values of surface soil did not show consistency in trend for the differences between the two land uses on both the slopes. Bulk density value of moist and dry surface soil was higher in orange orchard than in forest on both the hill slopes.
文摘Landslides are natural disasters which can pose a serious threat to human and property in many areas around the world. The Transient Rainfall Infiltration and Grid-based Regional Slope-stability (TRIGRS) model was used to investigate the rainfall-induced shallow landslides in a forested mountain region, Korea. Various input data for TRIGRS model include time-varying rainfall, topographic characteristics, soil depth, material strength, and hydraulic properties. A series of calculations were conducted in determining the slope stability over the Jangheung region in Korea during the storm occurred on August 6, 1998. The results show that TRIGRS model captured about 64.1% of landslides that were extracted from the IKONOS2 imageries. The model demonstrated how the factor of safety changed with time during a storm considering both the transient and spatial responses of pore water pressure in its slope stability calculation.
文摘Bird communities were surveyed in natural deciduous forest of both slope area and valley area at Mt. Gyebangsan (3740 30 N, 12830 1 E), Gangwon Province, South Korea in winter, spring, summer and autumn from September 2000 to November 2001. The investigating results showed that there existed differences in the bird species composition, richness, bird species diversity, guild structure between slope area and valley area, and the vertical forest structure, especially coverage of understory, and diameter at breast height (DBH) distribution also had significant difference between the two study areas. The differences in habitat structure between the areas are very likely to have influences on how birds used the available habitat.
基金This research was supported by Department of Sci-ence and Technology,Government of India,New Delhi,India vide its Project No.SP/SO/PS-52/2004
文摘The present study was undertaken in seven natural forest types of temperate zone (1500 to 3100 m, a.s.l.) of Garhwal Himalaya to understand the effects of slope aspects viz., north-east (NE), north-west (NW), south-east (SE) and south-west (SW), on the forest structure, composition and soil characteristics of each selected forest type. The sample plots in each forest type were laid out by using stratified random approach. The indices i.e., the Importance Value Index, Shannon-Wiener diversity index, Simpson’s concentration of Dominance, Simpson diver-sity index, Pielou equitability and Margalef species richness index were calculated statistically using standard softwares to elucidate the differ-ences in forest structure and composition of forest types on different slope aspects of the sites. The composite soil samples were taken from each forest stand and the physico-chemical properties of the soil i.e., moisture content (MC), water holding capacity (WHC), pH, organic carbon (OC), phosphorus (P), potassium (K) and available nitrogen (N) were analyzed. The results show that the higher values of total basal cover (74.4 m2·ha-1 in Quercus semecarpifolia forest), Concentration of dominance (0.85 in Pinus roxburghii forest) and Tree diversity (1.81 in Quercus floribunda forest) in the forests were recorded in the northern aspects. MC (40.8% in Quercus leucotrichophora forest), WHC (48.9% in Cupressus torulosa forest), OC (3.8% in Cedrus deodara forest), P (31.9 kg·ha-1 in Quercus leucotrichophora forest) and N (1.0% in Pinus roxburghii forest) had also higher values in the soils of northern aspects. Consequently the higher productivity of the forests was also noticed on the northern aspects.
基金supported by the National Natural Science Foundation of China (Grant No. 31370480)111 Project (B08044)Minzu University of China (MUC98507-08)
文摘This study uses DEM (Digital Elevation Model) data and remote sensing maps of the study area in 1993, 1999, and 2009 to analyze the slope gradient change of land use patterns in Qiandongnan Prefecture, Guizhou province, China. The land use data were classified into five types, forest, farmland, grassland, water and built-up, the slope gradients were divided into four grades. Indices for analyzing land use features were defined by their proportions, transformation matrixes, land use degree and changes The results showed that all land use types can be found at every gradient. Generally, with the slope degree increased, the area of forest being augmented as well, while the area of the other land use types (farmland, grassland and build-up) declined. Moreover, a mass of farmland were shifted from other land use types from o° to 25°, while a quantity of forest were transformed from the other land use types on 〉 25° from 2993 to 2009. In terms of land use degree and changes, the area of farmland and buildup land use types decreased when slope degree increased. Finally, we calculated the five landscape pattern metrics: Patch Density (PD) value, Largest Patch Index (LPI), Shannon's Diversity Index (SHDI), Area-Weighted Mean Shape Index (AWMSI) and Contagion Index (CONTAG). The results of metricsanalysis showed that PD values, SHDI values and CONTA values had a similar variation trend, that is, they decreased when slope degree increased. There was no obvious variation trend on LPI value.
文摘Status of organic carbon (C), total nitrogen (N), available potassium (K), calcium (Ca) and phosphorus (P) in three different depths (0-5 cm, 5-15 cm and 15?30 cm) on two hill slopes of 35% and 55% in orange orchard cultivated by the Mro tribe of Chittagong Hill Tracts (CHTs) were evaluated and compared with those in degraded bush forests, through digging three profiles in each land use. The content of all the five nutrients was found to be higher in the soil of orange orchard than in the soil of forest. But the variation was not consistent for both the slopes. The content varied depth wise also, having the highest value in surface soil in case of both the land uses on both the slopes. A mean available K content was significantly higher in orange orchard than in forest on 55% slope, while it was lower on 35% slope. Surface soil contained the nutrients of K and Ca with the amount of 0.2905-mg·g^(-1) soil and 3.025-mg·g^(-1)soil respectively in the orchard, while 0.1934-mg·g^(-1) soil and 1.6083-mg·g^(-1) soil were respectively in the forest. Organic carbon and total nitrogen were found more or less similar in surface soil on both the land uses showing a slight difference. Available P was found only in orange orchard, and in forest it was too little in amount to detect by the spectrophotometer. The degraded forests were poor in nutrient content due to high rate of soil erosion, which would be possible to be improved by bringing it under tree cover as proved by the adaptation of orange orchard there.
基金the research funding provided by the National Basic Research Program (973 Program No. 2007CB407206) of Chinathe National Natural Science Foundation of China (40771027)the National Supporting Plan of Science and Technology of China (2008BAD98B04)
文摘Soil erosion in hilly areas of the Sichuan Basin is a serious concern over sustainable crop production and sound ecosystem. A 3-year experiment was conducted using the method of runoff plots to examine the effects of terracing and agroforestry in farmland systems on soil and water conservation of slope fields in the hilly areas in Jianyang County, Sichuan Province, Southwestern China. A power function (Y = aXb) can statistically describe the relationship between water runoff (Y) and rainfall (X). The regression equation for the treatment of sloping terraces with crops (Plot 2) is remarkably different from that for the treatment of sloping terraces with grasses and trees (Plot 1) and the conventional up- and down-slope crop system (Plot 3) regarding equation coefficients, while regression equations are similar between Plot 1 and Plot 3. Water runoff amount and runoff coefficient of slope fields increased by 21.5~41.0 % and 27.5~69.7 % respectively, compared to those of sloping terraces, suggesting that terracing notably reduced the water runoff in the field. In the case of sloping terraces, lower amount of water runoff was observed on sloping terraces with crops than on sloping terraces with grasses and trees. Sediment yields on the slope fields in the normal year of rainfall distribution were notably higher (34.41~331.67 % and 37.06~403.44 % for Plot 1 and Plot 2, respectively) than those on sloping terraces, implying that terracing also plays a significant role in the reduction in soil erosion. It is suggested that terracing with crops is significantly effective for soil and water conservation in cultivatedfarmland, while the conventional practice of up- and down- slope cultivation creates high rates of water runoff and soil sediment transport. Terracing with grasses and fruit trees shows a less reduction in water runoff than terracing with crops, which was observed in the 3-year experiments.
文摘A study was conducted to investigate the effects of skid trail slope and traffic levels on soil disturbances at two soil depths (0--10 and 10-20 cm). The treatments were set at four traffic levels (2, 7, 12 and 20) two slope classes (〈20% and 〉20%) and two soil depths (0-10 and 10-20 cm). Results show that skidder traffic, longitudinal slope and soil depth have significant effect on soil bulk density in skid trail. Compari- son of average soil bulk density in different traffic levels shows that there are significant differences in average bulk density between different traffic levels and control (p〈0.05). The average bulk densities in different slopes and soil depths are significantly increased with increase in traffic levels, maximized at 12 passes (p〈0.05), but there are no significant differences between 12 and 20 passes. The interaction effects between traffic and soil depth are significant (F005,3=0.109, p〈0.001). For all traffic treatments, there are significant differences in soil moisture con- tent between the two slope classes and the two depths (p〈0.001). However, the interaction effects between traffic levels and slope classes are not significant (p 〉0.05), although skidder traffic and slope affected soil moisture content.
文摘This work was completed on the study of the southern slope scrublands (matorrals) of Tlemcen region in the northwest of Algeria (Western Algeria). These scrublands are under various states of degradation, made up of Quercus ilex, Juniperus oxycedrus, Thymus ciliatus, Rosmarinus officinalis. The problems sought in this study are to give the actual position of vegetable cover and in particular that of the formations to matorrals currently existing in the southern slope of the area of Tlemcen, while being based on the phytoecological aspect of the vegetable groupings which constitute this inheritance. Sampling is the first phase of work based on the analysis of the spatial variations of the structure and composition floristic and considering the nature of the problem to be treated, the authors considered to be useful to use the method Zuricho Montpeli6raine developed at the point by Braun-Blanquet, the method usually used consists to collect all the plant species and to make the list of the species on a small square of surface 100 m2 (have it minimal). The floristic readings (150 on the whole) were taken according to the method of Braun-Blanquet. Our results show that there exists a therophytisation marked by a general invasion of annual species as show us as the synergistic action of the aridity and the anthropic action generated important modifications on the level of the vegetation in the dynamic direction. This advanced degradation leads a steppisation which results in a substitution of the elements of the matorrals by species more adapted much the xericity.
文摘The paper gives two examples of larger construction projects with typical stability problems. The first example is from Sakhalin Island in the Russian Far East. It is connected with a construction of oil and gas pipelines through the mountainous terrain in Makarov region. The region has an active geotectonic history and is highly affected by uncontrolled erosion and extensive landslips. Basic principles of landslide hazard mitigation are presented. The second example is from a motorway construction in Azerbaijan. This motorway leads from Baku to Russia through a seismo-tectonically active area at the toe of Caucasian mountains and in some places is situated in deep cuts at the toe of high slopes. This unsuitable routing, together with seismic activity, led to a slope stability failure of a slope affected by recent tectonic movements near the village of Devechi. Stability conditions and designed remedy measures are presented.
基金We thank Ms. LIU Weili, Dr. CAI Wenhua, Mr. LIU Bo, and Dr. FANG Lei from the Institute of Ap- plied Ecology, Chinese Academy of Sciences for assis- tance in sampling and Dr. XIONG Jingbo from the Ningbo University of China for assistance in bioinfor- matic analysis. This research was supported by the Strategic Priority Research Program of Chinese Aca- demy of Sciences (No. XDB15010101), the National Basic Research Program (973 Program) of China (No. 2014CB954002), and the National Natural Science Foundation of China (No. 41371254).
文摘The effects of slope aspects on soil biogeochemical properties and plant communities in forested environments have been studied extensively; however, slope aspect influence on soil microbial communities remains largely unexamined, despite the central role of soil biota in ecosystem functioning. In this study, the communities of both soil bacteria and arbuscular mycorrhizal fungi (AMF) were investigated using tagged pyrosequencing for three types of slope aspects (south-facing aspect, north-facing aspect and flat area) in a boreal forest of the Greater Khingan Mountains, China. The bacterial and AMF community composition differed with slope aspects. Bacterial diversity was the lowest on the north-facing aspect, and AMF diversity was the lowest on the flat area. Aspects also had a significant impact on soil pH and available phosphorus (P) and shrubby biomass. Soil pH and understory shrub biomass were significantly correlated with bacterial communities, and soil available P and shrub biomass showed significant correlations with AMF communities. Our results suggested that slope aspects affected bacterial and AMF communities, mediated by aspect-induced changes in plant community and soil chemical properties (e.g., pH and available P), which improved the knowledge on the effects of forest slope aspects on aboveground and belowground communities.
文摘Green infrastructure is classic public goods which can be utilized by everybody simultaneously atany time of the day. Green infrastructure which is the interconnected system of green spaces that conservesnatural ecosystem values and functions, sustains clean air and water, not only provide a pleasant and naturalenvironment but also contribute to improving quality of life in urban areas. In other words green infrastructureis the communitys natural life support system and the ecological framework needed for environmental andeconomic sustainability in urban areas. Within this context, this paper offers an overview of green infrastructuredevelopment in Malaysia, its status, constraint, potential and future directions. The case study of KualaLumpur city, which is one of the fastest growing cities in the country, highlights the scenario of urban areasdevelopment in Malaysia. This includes the role played by the government agencies and non-governmentorganizations in developing and promoting forest areas as public parks. The provisions of recreational andeducational facilities in the parks as well as the protection measures of the resources undertaken by relevantauthorities are also discussed. This paper also highlights the response of the public to the opportunities beingprovided in these areas for recreation and education purposes.