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 หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Online Geospatial Database and Processing of Universal Soil Loss Equation Modeling for Optimum Assessment of Soil Loss in Songkhram Sub-Watershed, Northeastern Thailand) ผู้เขียน: บุรินทร์ ช้างน้อย สื่อสิ่งพิมพ์:pdf AbstractAn online geospatial database and processing system of universal soil loss equation modeling was designed and implemented, which included a distributed database designed to accommodate, organize and manipulate spatial data as well as interrelate data from various sources distributed by government offices. The system was used to produce erosion susceptibility maps for regions of Upper Northeastern Thailand—an area that has suffered from inappropriate land use practices. The OpenGeo software suite was used for online integration of the distributed database. GIS-based methods were proposed and applied to data from the Songkhram sub basin in the Mekong River basin. ArcGIS software was used to derive land use, land cover and topographical data for the watershed. An open source GIS (QGIS) and the Geographic Resources Analysis Support System (GRASS) package were used to carry out geographical data analysis and database management system implementation, both of which were implemented using the OpenGeo software suite. The watershed was mapped into topographically and geographically homogeneous grid cells to capture watershed heterogeneity. The results showed that during the study period, the area had soil losses that exceeded the tolerance level ranging from the moderate class up to the very severe class of susceptibility. Moreover, it was also found that the amount of soil erosion decreased to 499 km2 in 2010 from a predicted 1,123 km2. Keywords: optimal soil loss, distributed geodatabase, online geospatial |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : P-Factors in Universal Soil Loss Equation (USLE) of Various Conservation Practices on Hillslope at Mae Sa Integrated Watershed and Forest Land-use Project, Changwat Chiang M ผู้เขียน: ดร.นิพนธ์ ตั้งธรรม, ศาสตราจารย์ , Aphinan Korporn สื่อสิ่งพิมพ์:pdf AbstractP-factor in the USLE, the ratio of soil loss between conservation meausures plot and up and down plowing plot, of 4 soil conservation measures namely bench terrace (BT), intermittent terrace (IT), hillside ditch (HD), and contour bund (CB) was determined based on soil loss during 1980 to 1990 observed from three replications of 5?20 meter runoff plots on 30% slopling area at Mae Sa Integrated Watershed and Forest Land-use Project, Chiang Mai. Results showed that P-factor for BT, IT, HD and CB was averaged at 0.128, 0.245, 0.299 and 0.214 respectively. The same pattern of erosion control efficiency was also derived when P-factor was determined based on soil loss per a unit of rainfall factor and on mm of water loss. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Effectiveness of Grass Strips as Barrier Against Runoff and Soil Loss in Jijiga Area, Northern Part of Somali Region, Ethiopia) ผู้เขียน:Sultan Welle, ดร.ก่อโชค จันทวรางกูร, รองศาสตราจารย์ , ดร.ศุภกิจ นนทนานันท์, รองศาสตราจารย์ , นายสมเจตน์ จันทวัฒน์, ศาสตราจารย์ สื่อสิ่งพิมพ์:pdf AbstractIn this study, sixteen standard runoff plots with a dimension of 22.13 ? 1.8 m each were constructed in a contour on a cultivated land with slope gradient of 9 % in Jijiga area of the northern part of Somali region of Ethiopia at the end of the year 2003. To evaluate the effectiveness of grass strips as barrier against the runoff and soil loss, an experiment was laid out in randomized complete block design with four treatments by four replicates on the constructed sixteen runoff plots. The treatments were one control-without grass strip and three different grass strips of 1 m wide each. The grass strips, namely desho, setaria and vetiver were established at a spacing of 15 cm within a row on the lower end runoff plots. All the runoff and soil loss from the treatments were measured during 38 storm events in the years 2004 and 2005. The depth of sediment deposition along the strips and the growth rate of strips were also measured. In both 2004 and 2005 study years, the three grass treatments showed significantly lower annual runoff and soil loss results compared to the control treatment. However, the lowest runoff and soil loss were recorded from the vetiver grass. This was because of its faster growth rate than both the desho and setaria grass strips. The depositions of sediment along the three grass strip treatments were significantly higher than that of the control section, suggesting that three grass strips had the potential to cause terracing. However, the preference should be for the vetiver grass because it formed terraces much quicker than both the desho and setaria grass strips. In general, even though the three grasses could be used as barrier against runoff and soil loss, and had potential to cause terrace formation on gentle slope, it was however recommended that they should be rated as: vetiver>desho>setaria in accordance with their relative effectiveness. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Prediction of Soil Loss in the Northern Part of Somali Region of Ethiopia Using Empirical Soil Erosion Models) ผู้เขียน:Sultan Welle, ดร.ก่อโชค จันทวรางกูร, รองศาสตราจารย์, Supakij Nontanandh, นายสมเจตน์ จันทวัฒน์, ศาสตราจารย์ สื่อสิ่งพิมพ์:pdf AbstractTwo empirical soil loss models, namely Universal Soil Loss Equation (USLE) and Soil Loss Estimation Model for Southern Africa (SLEMSA) were applied to assess extent of erosion hazard at 12 selected sites in the northern part of Somali region of Ethiopia. The amount of estimated soil loss for 10 out of 12 sites by using the USLE is by two to three and half times greater than that estimated by SLEMSA. The difference between the values of soil loss estimated by the two models can be attributed to the difference in the sensitivity of the models to their input factors. In general, since SLEMSA under estimate the amount of soil loss from a given site, it is recommended to use USLE to estimate soil loss in the northern part of the Somali region of Ethiopia. The sensitivity of both models to their 20% increase or decrease in one of their input variable at a time while keeping other variables constant was analysed. The analysis indicated that USLE was highly sensitive to slope gradient factor (S), soil conservation practice factor (P) and rainfall erosivity factor (R) but less sensitive to slope length (L) and vegetal cover factor (C). Whereas, SLEMSA was ighly sensitive to change in rainfall kinetic energy (E) and soil erodibility (F) and was less sensitive to slope gradient (S), slope length (L) and percent cover factor (C). |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Runoff and Soil Loss of Vegetative Fallow and Farmland of South-Eastern Nigeria) ผู้เขียน:Iwara, A.I. สื่อสิ่งพิมพ์:pdf AbstractThe effects of two different land uses—namely, 10 year-old vegetation fallow land and farmland—on soil erosion and soil loss were investigated in a part of the rainforest zone of Nigeria. Measurements of 61 sites where rainfall had produced runoff and 54 sites where rainfall had generated soil erosion were carried out from March to November in the 2012 rainy season. The average runoff amounts for the 10 yr-old and farmland plots were 0.11 mm and 0.41 mm, respectively. The average soil loss for the 10 yr-old vegetation fallow land and farmland plots was 12.43 kg.ha-1 and 127.68 kg.ha-1, respectively. The differences in runoff and soil loss between the treatments were highly signifi cant (P < 0.001). The study showed that soil erosion had occurred on the 10 yr-old vegetation fallow plot even with greater aerial coverage conditions resulting in the loss of nutrient-rich topsoil, though the plot had signifi cantly reduced runoff and soil loss compared with the farmland plot. The signifi cant reduction in soil loss with increasing rainfall events on the 10 yr-old plot was indicative of the importance of vegetation in promoting good hydrological functioning in the area. The fi nding from the statistical analyses identifi ed rainfall as the principal cause of losses on the 10 yr-old fallow plot, while on the farmland, rainfall and tree girth were the main causes of soil erosion. The continuous loss of nutrient-rich topsoil, if not checked, may affect the ability of the degraded soil to replenish lost nutrient for subsequent farming. However, to reduce the rate of losses of both runoff and soil on cultivated farmlands, all trees should not be cut down during farming operations as is practiced in this part of the world. |
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