The Experts below are selected from a list of 40422 Experts worldwide ranked by ideXlab platform
Guangyao Gao - One of the best experts on this subject based on the ideXlab platform.
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spatial temporal variability of soil water content in a cropLand shelterbelt desert site in an arid inLand river basin of northwest china
Journal of Hydrology, 2016Co-Authors: Qin Shen, Guangyao GaoAbstract:Abstract Knowledge of the spatial-temporal variability of soil water content (SWC) is critical for understanding a range of hydrological processes. In this study, the spatial variance and temporal stability of SWC were investigated in a cropLand-shelterbelt-desert site at the oasis-desert ecotone in the middle of the Heihe River Basin, China. The SWC was measured on 65 occasions to a depth of 2.8 m at 45 locations during two growing seasons from 2012 to 2013. The standard deviation of the SWC versus the mean SWC exhibited a convex upward relationship in the shelterbelt with the greatest spatial variation at the SWC of around 22.0%, whereas a linearly increasing relationship was observed for the cropLand, desert, and Land Use Pattern. The standard deviation of the relative difference was positively linearly correlated with the SWC (p
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soil water content variations and hydrological relations of the cropLand treebelt desert Land Use Pattern in an oasis desert ecotone of the heihe river basin china
Catena, 2014Co-Authors: Qin Shen, Guangyao GaoAbstract:Abstract This study considered the cropLand-treebelt-desert system in the arid inLand river basin as an entire continuum to investigate the soil water content variation and hydrological relation. For this objective, the volumetric soil water content and plant root distribution was measured to 300 cm depth along a cropLand-treebelt-desert site at the oasis-desert ecotone in the Heihe River Basin, China. The results showed that the mean soil water content in the 0–200 cm layer was greater in the cropLand (8.88%) than that in the treebelt (5.78%) and desert (4.37%) as a result of frequent irrigation events. However, the cropLand had noticeably lower mean soil water content below 200 cm depth (14.27%), compared to treebelt (18.07%) and desert (17.30%) with deeper roots to suck up groundwater. The decline process in soil water content pulse of the cropLand and treebelt after irrigation event could be well described by an exponential decay function, and the soil water loss rate was greater in the cropLand (0.45–0.70%/day) than that in the treebelt (0.32–0.47%/day). The hydrological relation between treebelt and cropLand in the upper soil layer was mainly occurred by treebelt root water uptake from cropLand. The biomass of fine treebelt root extended into the cropLand decreased logarithmically with the distance from the cropLand-treebelt interface, which resulted in the smaller soil water content in the cropLand with more proximity to the treebelt. The hydrological relation in the lower soil layer among cropLand-treebelt-desert was caUsed by groundwater recharge, as cropLand irrigation raised up the groundwater level to replenish the deep soil layer. The results indicated that the percolation in the cropLand was an important water source for the growth of treebelt and desert plants. This study could provide scientific basis for Land Use Pattern design and water resources management in the arid inLand river basin.
Qin Shen - One of the best experts on this subject based on the ideXlab platform.
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spatial temporal variability of soil water content in a cropLand shelterbelt desert site in an arid inLand river basin of northwest china
Journal of Hydrology, 2016Co-Authors: Qin Shen, Guangyao GaoAbstract:Abstract Knowledge of the spatial-temporal variability of soil water content (SWC) is critical for understanding a range of hydrological processes. In this study, the spatial variance and temporal stability of SWC were investigated in a cropLand-shelterbelt-desert site at the oasis-desert ecotone in the middle of the Heihe River Basin, China. The SWC was measured on 65 occasions to a depth of 2.8 m at 45 locations during two growing seasons from 2012 to 2013. The standard deviation of the SWC versus the mean SWC exhibited a convex upward relationship in the shelterbelt with the greatest spatial variation at the SWC of around 22.0%, whereas a linearly increasing relationship was observed for the cropLand, desert, and Land Use Pattern. The standard deviation of the relative difference was positively linearly correlated with the SWC (p
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soil water content variations and hydrological relations of the cropLand treebelt desert Land Use Pattern in an oasis desert ecotone of the heihe river basin china
Catena, 2014Co-Authors: Qin Shen, Guangyao GaoAbstract:Abstract This study considered the cropLand-treebelt-desert system in the arid inLand river basin as an entire continuum to investigate the soil water content variation and hydrological relation. For this objective, the volumetric soil water content and plant root distribution was measured to 300 cm depth along a cropLand-treebelt-desert site at the oasis-desert ecotone in the Heihe River Basin, China. The results showed that the mean soil water content in the 0–200 cm layer was greater in the cropLand (8.88%) than that in the treebelt (5.78%) and desert (4.37%) as a result of frequent irrigation events. However, the cropLand had noticeably lower mean soil water content below 200 cm depth (14.27%), compared to treebelt (18.07%) and desert (17.30%) with deeper roots to suck up groundwater. The decline process in soil water content pulse of the cropLand and treebelt after irrigation event could be well described by an exponential decay function, and the soil water loss rate was greater in the cropLand (0.45–0.70%/day) than that in the treebelt (0.32–0.47%/day). The hydrological relation between treebelt and cropLand in the upper soil layer was mainly occurred by treebelt root water uptake from cropLand. The biomass of fine treebelt root extended into the cropLand decreased logarithmically with the distance from the cropLand-treebelt interface, which resulted in the smaller soil water content in the cropLand with more proximity to the treebelt. The hydrological relation in the lower soil layer among cropLand-treebelt-desert was caUsed by groundwater recharge, as cropLand irrigation raised up the groundwater level to replenish the deep soil layer. The results indicated that the percolation in the cropLand was an important water source for the growth of treebelt and desert plants. This study could provide scientific basis for Land Use Pattern design and water resources management in the arid inLand river basin.
Klaus Hubacek - One of the best experts on this subject based on the ideXlab platform.
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on the relationship between Landscape ecological Patterns and water quality across gradient zones of rapid urbanization in coastal china
Ecological Modelling, 2015Co-Authors: Martin Kappas, Salman Qureshi, Klaus HubacekAbstract:Abstract In order to improve water quality and ecosystems health, the focus of river ecological restoration and water ecosystem-based management needs to reach beyond its usual policy domain by restricting the expansion of urban built-up Land and reducing urbanization-related pollution. This study aims to assess the impacts of urbanization on water quality for three spatial urban development zones, i.e. center, inner peri-urban and outer peri-urban of the eastern coastal municipality of Lianyungang, China. We analyze the relationship between urban Landscape ecological Pattern and water quality in three Landscape zones. The study explores this relationship and its policy implications. The results of our analysis are as follow: (1) In the center zone, the Landscape Pattern metrics, largest patch index (LPI) and total class area (CA) were strongly correlated with water quality parameters, such as CODMn and NH3–N; (2) In the inner peri-urban zone, the number of significant relations of Land Use Pattern metrics and water quality parameters in 2008 was greater than that in 2000 and 2004; (3) Land Use Pattern metrics in the outer peri-urban were less correlated to water quality than in the other zones; (4) the degree of correlation in different spatial zones was in following order: center (2008 > 2000 > 2004), inner peri-urban (2008 > 2000 > 2004), outer peri-urban (2004 > 2000 = 2008). Thus, the relationships between Landscape and water quality varies significantly over space due to varying watershed characteristics and pollution sources across space.
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spatial and temporal dynamics of Land Use Pattern in district swat hindu kush himalayan region of pakistan
Applied Geography, 2011Co-Authors: Muhammad Qasim, Klaus Hubacek, Mette Termansen, Ahmad KhanAbstract:Abstract District Swat is a part of the high altitude Hindu Kush Himalaya (HKH) region of Pakistan comprising a diverse set of biophysical, ecological and socio-economic characteristics. Analysis of Land cover data of this region is particularly important becaUse of disparate accounts on the state of forest resources of Pakistan in general and Swat in particular. Mainly official Pakistani sources frequently claim that Pakistan’s forests have been progressively increasing as a result of afforestation efforts and increasing environmental awareness. On the other hand, a number of studies and international statistics have reported significant deforestation in Pakistan. To resolve this uncertainty this paper documents the Land Use dynamics from three ecological zones of district Swat over four decades using aerial photographs and remote sensing data for the years 1968, 1990 and 2007. Analysis of Land Use and cover change in Swat, over this time period, shows drastic changes in the Landscape. In Kalam; the forest zone of the district, forest area is decreased by 30.5%; with 11.4% of the deforestation caUsed by agricultural expansion. Simultaneously, a marked reduction in the agricultural area was observed with 17.3% of the agricultural area converted to rangeLand. In Malamjaba, the agro-forest zone of the district, agricultural Land expanded by 77.6% between 1968 and 1990 but then shrunk by 4.1% between 1990 and 2007. Forest cover in this zone decreased 49.7% over the last 40 years. In the Barikot region (agro-scrub forest zone), forest cover decreased from covering 32.7% of the total area of the zone in 1968 to 9.5% in 2007, whereas the built up areas increased by 161.4% over the four decades; and agricultural Land expanded by 129.9% consuming 12.7% and 18.96% of forest area between 1968 and 1990, and between 1990 and 2007, respectively. Annual deforestation rates observed were 1.86% (scrub forest zone), 1.28% (agro-forest zone) and 0.80% (pine forest zone) in the respective areas of district Swat. Expansion of agriculture has mainly been achieved at the expense of forested areas, with only negligible accounts of afforestation from 1968 to 2007. We conclude that despite frequent claims of forest increase in Swat, the valuable coniferous forest has significantly decreased, frequently leading to Land degradation. The current trend is therefore alarming and calls for increased policy action to increase protection of the remaining forest resources which otherwise might follow a similar fate.
Chi Peng - One of the best experts on this subject based on the ideXlab platform.
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spatial Pattern of heavy metals accumulation risk in urban soils of beijing and its influencing factors
Environmental Pollution, 2016Co-Authors: Rui Liu, Meie Wang, Weiping Chen, Chi PengAbstract:Accumulations of heavy metals in urban soils are highly spatial heterogeneity and affected by multiple factors including soil properties, Land Use and Pattern, population and climatic conditions. We studied accumulation risks of Cd, Cu, Pb and Zn in unban soils of Beijing and their influencing based on the regression tree analysis and a GIS-based overlay model. Result shows that Zinc caUses the most extensive soil pollution and Cu result in the most acute soil pollution. The soil's organic carbon content and CEC and population growth are the most significant factors affecting heavy metal accumulation. Other influence factors in Land Use Pattern, urban Landscape, and wind speed also contributed, but less pronounced. The soils in areas with higher degree of urbanization and surrounded by intense vehicular traffics have higher accumulation risk of Cd, Cu, Pb, and Zn.
Salman Qureshi - One of the best experts on this subject based on the ideXlab platform.
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on the relationship between Landscape ecological Patterns and water quality across gradient zones of rapid urbanization in coastal china
Ecological Modelling, 2015Co-Authors: Martin Kappas, Salman Qureshi, Klaus HubacekAbstract:Abstract In order to improve water quality and ecosystems health, the focus of river ecological restoration and water ecosystem-based management needs to reach beyond its usual policy domain by restricting the expansion of urban built-up Land and reducing urbanization-related pollution. This study aims to assess the impacts of urbanization on water quality for three spatial urban development zones, i.e. center, inner peri-urban and outer peri-urban of the eastern coastal municipality of Lianyungang, China. We analyze the relationship between urban Landscape ecological Pattern and water quality in three Landscape zones. The study explores this relationship and its policy implications. The results of our analysis are as follow: (1) In the center zone, the Landscape Pattern metrics, largest patch index (LPI) and total class area (CA) were strongly correlated with water quality parameters, such as CODMn and NH3–N; (2) In the inner peri-urban zone, the number of significant relations of Land Use Pattern metrics and water quality parameters in 2008 was greater than that in 2000 and 2004; (3) Land Use Pattern metrics in the outer peri-urban were less correlated to water quality than in the other zones; (4) the degree of correlation in different spatial zones was in following order: center (2008 > 2000 > 2004), inner peri-urban (2008 > 2000 > 2004), outer peri-urban (2004 > 2000 = 2008). Thus, the relationships between Landscape and water quality varies significantly over space due to varying watershed characteristics and pollution sources across space.
