The Impacts of Land-Use Input Conditions on Flow and Sediment Discharge in the Dakbla Watershed, Central Highlands of Vietnam

The main objective of this study was to evaluate various land-use input conditions in terms of the performance improvement found in consequent flow and sediment simulations. The soil and water assessment tool (SWAT) was applied to the Dakbla watershed from 2000 to 2018. After the calibration and validation processes, dissimilar effects between the input conditions on the flow and sediment simulations were confirmed. It was recognized that the impact of the land use on the sediment simulation was more sensitive than with the flow simulation. Additionally, through monthly evaluation, the effects against the flow and sediment in the rainy season were larger than those in the dry season, especially for sediment simulation in the last three months from October to December. Changing land-use conditions could improve flow and sediment simulation performance better than the performance found with static land-use conditions. Updated land-use inputs should be considered in simulations if the given land-use condition changes in a relatively short period because of frequent land-use policy changes by a local government

Organic Matter Clogging Results in Undeveloped Hardpan and Soil Mineral Leakage in the Rice Terraces in the Philippine Cordilleras

Rice terraces in Cordillera, Philippines, a world cultural heritage site, are threatened by the risk of collapse. It is crucial to manage these rice terraces for their conservation, while simultaneously practicing traditional farming. We examined the soil environment and investigated its effects on rice terrace conservation, by focusing on the hardpan condition; infiltration process, which is related to the collapse of rice terraces; and soil nutrition conditions in these sites. Field survey and soil analysis revealed that in areas where the hardpan was not sufficiently developed and water infiltration was effectively suppressed, organic matter content was significantly high, suggesting organic matter clogging. In these rice terraces, the amounts of P, K, Ca, and Mn were significantly low, showing the mineral leaching under reductive soil conditions. Therefore, hardpan formation, rather than organic matter clogging, is essential for the suppression of infiltration and prevention of potential terrace collapse. Because hardpan formation or organic matter clogging cannot be identified from the surface of flooded rice paddies, it is difficult to identify the influencing factor. Thus, we suggest that the hard soil layer should be checked before the planting season and drainage is allowed after the cropping season in the rainy season

Effects of local land-use policies and anthropogenic activities on water quality in the upstream Sesan River Basin, Vietnam

Study region: This study focuses on the upstream Sesan River Basin in the Central Highlands of Vietnam. Study focus: Local land-use policies and human activities can significantly affect hydrology and increase the magnitude of erosion and nutrients in downstream areas. The effects in terrestrial regions on water quality of the target area were evaluated during the 2000-2018 period using the SWAT (Soil and Water Assessment Tool) with updated land-use conditions following the local policy decisions and agricultural practices in different periods. New hydrological insights for the regions: This study indicates that the implementation of the local land-use policies, along with extensive anthropogenic activities, has had significant effects on the downstream aquatic environment as compared with the period before the implementation of the land-use policies. Higher annual sediment, total nitrogen (TN), and total phosphorus (TP) load-ings were found upstream from the Poko Watershed, where range land predominated, and in southern and southwestern Dakbla Watershed, where arable land and permanent cropland pre-dominated. Arable land had the highest proportion of sediment and nutrient loadings into the reach, especially in the 2005-2009 period (conducting afforestation, agricultural expansion, and urbanization) and in the 2010-2014 period (applying crop conversion policy involving a shift from mixed forests to rubber forests). Understanding the watershed characteristics along with the combination of spatial land use, local land-use policies, and agricultural practices will support the implementation of regional land use and water resources management strategies more comprehensively

Environmental flow sustainability in the Lower Limpopo River Basin, Mozambique

Study region: This study focuses on the Lower Limpopo River basin (LLRB) in Mozambique, Africa. Study focus: Maintaining environmental flows necessary for ecosystem sustainability represents a significant challenge to water resource management. In this study the sustainability of LLRB was evaluated by comparing hydrologic availability with ecological and anthropogenic needs. Current river ecological status was scored with a habitat integrity index verified through ground-truthing field surveys and aerial imagery data. Local stakeholder interviews were used to further evaluate the habitat index scores. Deficiencies between water availability and ecological-human requirements were assessed with a water scarcity index. New Hydrological Insights for the Region: Four environmental flow categories defined as "Excellent", "Fair", "Poor", and "Degraded" coincided to approximately 50 %, 39 %, 27 %, and 14 % of the natural mean annual flow, respectively. Stakeholder interview responses indicated annual water shortages currently occur between August and November and coincide with "Poor" and "Degraded" environmental flow conditions. Water supplies appear to meet consumption needs when calculated on an annual basis with the water scarcity index. However, when calculated monthly, there is not enough to meet human water demand between August and October. This deficit period will likely expand from June to November due to projected increases in future water demands. As the greatest water use in the basin is agricultural irrigation, long-term environmental flows sustainability will likely depend upon effective irrigation management

Myocardial velocity gradient as a noninvasively determined index of left ventricular diastolic dysfunction in patients with hypertrophic cardiomyopathy

AbstractObjectivesWe investigated the utility of the peak negative myocardial velocity gradient (MVG) derived from tissue Doppler imaging (TDI) for evaluation of diastolic dysfunction in patients with hypertrophic cardiomyopathy (HCM).BackgroundHypertrophic cardiomyopathy is characterized by impaired diastolic function with abnormal stiffness and prolonged relaxation. However, it remains difficult to evaluate these defects noninvasively.MethodsBoth TDI and conventional echocardiography were performed in 36 patients with HCM and in 47 control subjects. Left ventricular (LV) pressure was measured simultaneously in all HCM patients and in 26 controls.ResultsThe peak negative MVG occurred soon after the isovolumic relaxation period during the initial phase of rapid filling (auxotonic relaxation). It was significantly smaller in HCM patients than in control subjects (2.32 ± 0.52/s vs. 4.82 ± 1.15/s, p < 0.0001); the cutoff value for differentiation between all HCM patients and 47 normal individuals was determined as 3.2/s. Both the left ventricular end-diastolic pressure (LVEDP) (19.6 ± 6.1 mm Hg vs. 6.5 ± 1.7 mm Hg, p < 0.0001) and the time constant of LV pressure decay during isovolumic diastole (tau) (44.0 ± 6.7 ms vs. 32.1 ± 5.5 ms, p < 0.0001) were increased in HCM patients compared with controls. The peak negative MVG was negatively correlated with both LVEDP (r= −0.75, p < 0.0001) and tau (r= −0.58, p < 0.0001).ConclusionsA reduced peak negative MVG reflects both prolonged relaxation and elevated LVEDP. The peak negative MVG might thus provide a noninvasive index of diastolic function, yielding unique information about auxotonic relaxation in patients with HCM

Mercury pollution in the soil and river water of the Ratai watershed by artisanal and small-scale gold mining activities in Pesawaran District, Lampung, Indonesia

The high risk of mercury pollution in the Ratai watershed due to artisanal and small-scale gold mine activities in Pesawaran District, Lampung, Indonesia, was evaluated. Studies are needed to improve the understanding of the effect of heavy metal pollution, especially mercury (Hg), in soil and river water along the watershed because of erosion. The Universal Soil Loss Equation (USLE) integrated with Geographic Information Systems (GIS) model was used to analyze the transport of mercury (Hg) from nonpoint source pollution loads to the Way Ratai River using rainfall-based erosion. Soils and river water samplings were conducted in 2020. Biophysical conditions, the land cover, and the rainfall data of the Ratai watershed were also taken into account. The results indicated that Hg concentrations in the soil and the river water were high, ranging from 0.26-28.9 mg L-1 and from 0.08-14.1 mg L-1, respectively. The reason for the high Hg contents in the soils and the river waters was the high erosion rate in the watershed. As the study area was characterized by high rainfall erosivity and low to high soil erodibility, the erosion-caused Hg contamination in soil and water can be significant if no conservation strategies are developed

コウブツユアジュバントトキンタイナイドクソノマウスニオケルコウタイサンセイニタイスルアジュバントサヨウノケンキュウ

京都大学0048新制・課程博士理学博士甲第982号理博第188号新制||理||126(附属図書館)2791UT51-45-M192京都大学大学院理学研究科動物学専攻(主査)教授 加藤 幹太, 教授 加藤 勝, 教授 岡田 節人学位規則第5条第1項該当Kyoto UniversityDA

Efficient agricultural monitoring: a methodology for assessing individual farmer adherence to rice-planting schedule for tertiary irrigation system under the Muda Irrigation Scheme using Earth observation datasets

The tertiary irrigation system (TIS) was designed for the Muda Irrigation Scheme (MIS) to distribute irrigation water to farmers' fields to ensure the reliability of water supply for cultivating rice paddies twice a year. Variability in farming practices, influenced by farmer autonomy along the tertiary canal adds complexity and uncertainty to adherence monitoring. Traditional on -site data collection methods are limited in scope and efficiency, whereas Earth observation (EO) enables continuous monitoring. In this study, we introduced a methodology that uses EO datasets to monitor individual field adherence to rice -planting schedules under TIS. These tools improve the monitoring of rice -planting schedule adherence by identifying non -adherent fields for further countermeasures. This study highlights the potential use of EO datasets and advanced data processing techniques for efficient agricultural monitoring