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The Soils of the South-eastern Coastal Area. Part 2. The Soils of upper Hajar Valley.

Field document 21








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    Project
    Soil Survey and Land Classification, Republic of Yemen. Land suitability for irrigated sorghum (Seifi) in Wadi Mawr (Tihama).
    Technical Note 8.
    1991
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    The purpose of this evaluation is to determine the land suitability of the Wadi Mawr area for the cultivation of (spate) irrigated sorghum under improved traditional management, and to determine the yield response to additional water gifts on various soil types. The evaluation was carried out for the alluvial plain, i.e. hills, dunes and wadi beds were excluded, and takes into account the following soil qualities and characteristics: drainage, salinity of the rootzone, surface sealing and the oc currence of crusts, effective soil depth and the available water holding capacity of the rootzone.
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    Land Resource Study of Hodeidah Green Belt Area.
    Field document 12.
    1997
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    In this report the results are presented from the soil survey carried out in the Green Belt area around Al-Hodeidah. This report covers the relevant parts of the Tihama coastal plain, including part of the wadi Siham alluvial plain. A soil map, land use map, vegetation map and physiographic map, all at a scale of 1 : 50.000, were prepared. The total area covered is approximately 15200 ha, situated in a half circle around Hodeidah city. The soils are in general homogeneous with little pedogenetic development, and variable degrees of salinity and sodium content. Apart from the more sandy soils that generally cover the coastal plain, the flood irrigated alluvial parts have more loamy textures. These soils have a low organic matter content, moderate fertility and a moderate internal drainage. The quality of groundwater used for irrigation is poor with high levels of sodium. The soil map indicates that about 25% of the area is occupied by active duneland, and another 35% consists of flat an d hummocky sandy areas affected by shifting sands. These areas are used mainly for grazing. A considerable part of the survey area (about 40%) is used for traditional rainfed and irrigated farming by mainly small scale farmers.
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    Examining the applicability of UAV-based photogrammetry to assess sediment yield from small fire-affected forests
    XV World Forestry Congress, 2-6 May 2022
    2022
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    Forest clearance after a fire is commonly implemented in fire-affected forests in South Korea, removing damaged vegetation and ash-litter layers. It undoubtedly affects hydrological processes, thereby leads to severe soil erosion to the downstream waterbodies such as stream, reservoir, dam. Therefore, accurate understanding of the magnitude of sediment yields is a prerequisite to implement the sediment control measures in the fire-affected region. Over the past decades, direct field measurement of sediment yields has been conducted over the world, particularly in South Korea. The traditional field survey has restricted to the application due to requiring a lot of labor and time and is only used to small and limited area. In this study, we tried to overcome the limitations of traditional approach by monitoring the sediment yield variations through images obtained from UAVs. For this purpose, direct field survey and UAV image-based photogrammetry were conducted on erosion control dams located in the downstream of mountain terrain. A comparison of sediment deposition in the dams were done to assess the applicability and reliability of UAV photogrammetry in forest sectors. The results show that UAV-derived photogrammetry technique can be considered as the alternative of field surveying when estimates the relief and terrain shape in a site where direct access and available resource are limited. This study may introduce a simple and accurate methodology for measuring soil loss and sediment yield on degraded mountain areas. Keywords: Monitoring and data collection ID: 3623072

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