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Research Interests: Geology and Mass Movement
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Research Interests: Geology and Mass Movement
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We examined soil‐water response in a hillslope with multi‐layered volcanic soils affected by fissures formed by intense shaking during the 2016 Kumamoto earthquake in Japan. Pressure head and volumetric water content responses in a... more
We examined soil‐water response in a hillslope with multi‐layered volcanic soils affected by fissures formed by intense shaking during the 2016 Kumamoto earthquake in Japan. Pressure head and volumetric water content responses in a 6 × 20 m hillslope ridgeline plot were monitored by tensiometers and capacitance‐based soil moisture sensors, respectively. The plot contained seven seismic fissures (0.3–0.8 m deep and 0.4–2.2 m wide) formed parallel to the ridgeline that exposed underlying soil layers, while areas with topsoil occurred between the fissures. Among the alternating layers, the andisol (ca. 1.0 m deep) consistently experienced high pressure heads (>−150 cm H2O) and volumetric water contents (>0.58 cm3 cm−3), indicating high water‐holding capacity. This andisol was a key layer for storing soil water and causing slow drainage into the deeper matrix, resulting in abrupt increases in volumetric water content during storms. Rainwater directly reaching the bottom of fissures without percolating through the topsoil caused rapid soil‐water response compared to the soil layer where water percolated via topsoil. Analysis of in‐situ soil water retention curves, recession rates and water storage changes revealed that the second andisol had unique characteristics for retaining water in the hillslope. The findings of this study show that spatial and temporal variability of soil water responses varied associated with earthquake‐induced fissure formation and soil water characteristics of multi‐layered volcanic soils.
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<p>Snow avalanches are one of the most predominant natural hazards in mountain areas. Every year throughout the world, they are the cause of much material destruction and loss of life. It is therefore essential for... more
<p>Snow avalanches are one of the most predominant natural hazards in mountain areas. Every year throughout the world, they are the cause of much material destruction and loss of life. It is therefore essential for local communities and public authorities to assess areas most vulnerable to avalanches. Here, we propose a new method for automatic avalanche detection from Landsat archives, using a snow index. This open-source and user-friendly model in Google Engine is the first to automatically inventory all the avalanches that have occurred each year across wide catchment areas, over a period of 32 years. The Snow Avalanche Frequency Estimation (SAFE) model was tested in the mountains of Afghanistan - Amu Panj Basin - one of the most remote regions in the world and one of the poorest in terms of avalanche monitoring. SAFE correctly detected 76% of the actual avalanches identified on Google Earth images and in the field. Since 1990, this region of Afghanistan has been impacted by 810,000 avalanches with an average frequency of 0.88 avalanches/km²yr<sup>-1</sup>. With SAFE, it is now possible to clearly identify villages, roads, and rivers that are frequently affected by avalanches and thus help decision-makers in their investments in avalanche protection infrastructure. It was also found that the frequency of avalanches has not changed over the last 32 years, but SAFE has identified a northeast shift of these hazards, notably due to a slight increase in temperatures in the south at the beginning of winter. SAFE is the first robust model that can be used worldwide and is capable of filling data voids on snow avalanche impacts in inaccessible regions.</p>
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Research Interests: Geology and Mass Movement
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Research Interests: Earth Sciences, Environmental Science, Biological Sciences, Phosphorus, Environmental Sciences, and 15 moreMagnesium, Copper, Fossil Fuels, Heavy Metal, Environmental Effect, Chromium, Nickel, Environmental quality, Acid Soil, Industrial Waste, Chemical Reaction, Organic Matter, Environment Quality, Fluidized Bed Combustion, and Coal Fired Power Plant
Municipal wastewater has been used to spray irrigate reed canary grass and corn over periods of 10 and 11 years, respectively, on clay loam soil. Average concentrations of copper, zinc, cadmium, lead, nickel, and cobalt in the applied... more
Municipal wastewater has been used to spray irrigate reed canary grass and corn over periods of 10 and 11 years, respectively, on clay loam soil. Average concentrations of copper, zinc, cadmium, lead, nickel, and cobalt in the applied effluent were 68, 197, 2.7, 140, 50, and 40 parts per billion, respectively. The corresponding metal concentrations in an effluent-sludge mixture used
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The background, development, and proposed future directions in the emerging discipline of hydrogeomorphology are presented. The need for better understanding of temporal and spatial linkages in hydrogeomorphology is suggested as one of... more
The background, development, and proposed future directions in the emerging discipline of hydrogeomorphology are presented. The need for better understanding of temporal and spatial linkages in hydrogeomorphology is suggested as one of the primary reasons for the internal inaccuracies of many hydrological and sedimentation models, especially because many hydrogeomorphic processes are non steady-state. Examples are presented of the types of temporally and spatially distributed process information that are necessary to evaluate stormflow generation and sediment movement within catchments. Such detailed knowledge of spatial and temporal behaviour is needed to provide management guidelines for sustainable land use activities in catchments. A conceptual model for assessing the effects of land use and other external factors shows that thresholds for natural hydrogeomorphic processes are significantly altered by anthropogenic factors. The need to incorporate spatial and temporal hydrogeomorphic linkages into predictions and models in a relatively simple but meaningful way is stressed; such attempts to date have not focused on internal catchment processes and, thus, are not good analogues for catchment management.
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ABSTRACT Knowledge of the effects of forest roads on biogeochemical processes within headwater catchments is limited in the tropics. Hydrological response along with fluxes and yields of fine sediment (< 250 mm) and dissolved... more
ABSTRACT Knowledge of the effects of forest roads on biogeochemical processes within headwater catchments is limited in the tropics. Hydrological response along with fluxes and yields of fine sediment (< 250 mm) and dissolved nutrients (e.g., DOC and K+) were measured from a 50-m segment of logging road and the greater catchment (13 ha; harvested in winter 1999-2000) in Peninsular Malaysia during four consecutive storms in December 2002. Due to very low infiltration capacities, Hortonian overland flow was generated almost instantaneously on the road surfaces during the storm events. Maximum specific flux of sediment, DOC and K+ were observed during the fourth storm with the highest intensity, precipitation, and antecedent moisture: 5.15 kg/sec/ha, 473 g/sec/ha, and 465.81 g/sec/ha at the road segment; and 37.81 g/sec/ha, 53.27 mg/sec/ha, and 17.83 mg/sec/ha at the catchment outlet, respectively. The average enrichment ratio, i.e., road yield divided by catchment average yield on an unit area basis, for four storms was always greater than ten-fold (72.3, 16.1, and 12.4 for sediment, DOC, and K+, respectively), indicating the road surface produced disproportionately high amounts of those elements relative to the other parts of the catchment. The relatively high enrichment ratio for sediment relative compared to DOC and K+, suggests that subsurface and riparian sources also contributed to fluxes of dissolved nutrients. Furthermore, the enrichment ratio for DOC and K+ were generally higher during low intensity storms, indicating that a higher proportion of the catchment yield was attributed to roads, probably because the other parts of the catchment were not as hydrologically responsive. Thus, even for relatively small rain events with dry antecedent conditions, forest roads may alter internal biogeochemical pathways by acting as a source of dissolved nutrient and sediment (with adsorbed nutrients) and by redirecting natural hydrological pathways into the stream.
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This book emphasizes the natural factors affecting slope stability, including soils and geomorphic, hydrologic, vegetative, and seismic factors and provides information on landslide classification, global damage, and analytical methods.... more
This book emphasizes the natural factors affecting slope stability, including soils and geomorphic, hydrologic, vegetative, and seismic factors and provides information on landslide classification, global damage, and analytical methods. The effects of various extensive and intensive land management practices on slope stability are discussed together with methods for prediction, avoidance, and control. Examples of terrain evaluation procedures and land management
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Soybeans (Glvcine max L.) cv. “Clark”; were grown in the greenhouse in sand‐filled plastic pots sub‐irrigated with Hoagland No. 1 solution to determine the possible inhibitory effects of Zn on the uptake of P. Zinc rates used were 0.05... more
Soybeans (Glvcine max L.) cv. “Clark”; were grown in the greenhouse in sand‐filled plastic pots sub‐irrigated with Hoagland No. 1 solution to determine the possible inhibitory effects of Zn on the uptake of P. Zinc rates used were 0.05 (control), 0.25, 0.5 and 2.5 ppm. Yields equalled the control at Zn levels of 0.25 and 0.5 ppm, but plants grown in solutions containing 2.5 ppm Zn were stunted severely. Foliar Zn and P levels differed very little among Zn treatments. Zinc levels were highest and P levels were lowest, however, in the roots and stems of soybeans grown in solutions of 2.5 ppm Zn. Zinc and P uptake was significantly inhibited in the leaves, stems and roots of plants grown at the highest Zn rate. The recycling of wastes containing high Zn content could adversely affect plant growth by a suspected antagonism with P.
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Research Interests: Earth Sciences, Environmental Science, Chemistry, Irrigation, Energy Conservation, and 15 moreBiological Sciences, Environmental Sciences, Sewage sludge, Waste Disposal, Environmental Effect, Zinc, Cadmium, Oak, Environmental quality, Acer rubrum, Forest ecosystem, Waste Water, Early Terrestrial Ecosystems, Effluent, and Environment Quality
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Research Interests: Environmental Engineering, Civil Engineering, Environmental Science, Forestry, Landslides, and 15 moreMonsoon, Canopy, Canopy Interception, Soil moisture, Moisture, Rain, Landslide, Rainfall, Secondary Forest, Interception, Pore Pressure, Pressure Distribution, Porewater, Forest Canopy, and soil moisture dynamics
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Living mulch (LM) is used in agricultural fields to suppress weeds, control diseases, and mitigate erosion. It also enhances soil nutrient supply at the root death and decay stage during the growing season. However, benefits of LM to soil... more
Living mulch (LM) is used in agricultural fields to suppress weeds, control diseases, and mitigate erosion. It also enhances soil nutrient supply at the root death and decay stage during the growing season. However, benefits of LM to soil hydraulic properties related to soil pore structure have not been elaborated here. We focus on temporal changes in soil hydraulic conductivity (K) in a field where sweet potato was grown with and without LM (barley, Hordeum vulgare L.). K was measured in the field using a mini‐disk infiltrometer at three different pressure heads. In the plots with LM, K decreased significantly in August and then increased in October compared to plots without LM (at –0.5 cm pressure head). Changes in soil pore structure due to root growth or death and decay may alter soil hydraulic conductivity.
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Sitka spruce (Piceasitchensis (Bong.) Carr.) seedlings colonized by the ectomycorrhizal fungi Laccarialaccata (Scop. ex Fr.) Berk and Br., Hebelomacrustuliniforme (Bull, ex St. Amans) Quel., or Cenococcumgeophilum Fr. and a noninoculated... more
Sitka spruce (Piceasitchensis (Bong.) Carr.) seedlings colonized by the ectomycorrhizal fungi Laccarialaccata (Scop. ex Fr.) Berk and Br., Hebelomacrustuliniforme (Bull, ex St. Amans) Quel., or Cenococcumgeophilum Fr. and a noninoculated control were planted on rotten wood, undisturbed duff, undisturbed duff on the north side of large stumps, and exposed mineral soil in an area recently clear-cut on Chichagof Island, southeast Alaska. Uptake and concentrations of N, P, K, Ca, Mg, and several micronutrients in foliage, stems, and roots were determined 2 years after outplanting. There were no significant interactions between fungal treatments and microsite types for uptake or concentration of any nutrient. Uptake and concentrations of N and P in foliage and roots did not differ significantly among fungal treatments. Foliar K and Cu concentrations were significantly higher in control seedlings than in those with L. laccata ectomycorrhizae. Calcium was the only nutrient analyzed that was present in higher concentrations in seedlings inoculated with H. crustuliniforme than in controls. Concentrations of foliar P, Mn, and Zn were significantly greater in seedlings grown on undisturbed duff (protected north side) than in seedlings grown on exposed mineral soil. However, foliar concentrations of all nutrients tested were not significantly different between seedlings grown on undisturbed duff (unprotected sites) and those grown on mineral soil. Seedlings grown on rotten wood had significantly greater concentrations of foliar Ca than seedlings grown on either exposed mineral soil or undisturbed duff. The on-site colonization of control seedlings after outplanting indicates that resident ectomycorrhizal fungi readily establish and appear to provide equal if not improved nutrient benefits compared to inoculated seedlings. Greater nutritional benefits were derived by planting on certain microsite types (duff and protected duff) than by inoculating with specific ectomycorrhizal fungi.