Evapotranspiration is an important component in many hydrological, ecological and agricultural studies. There are many available direct and indirect methods to determine the evapotranspiration rate. In this study, alternative model based on multilayer Artificial Neural Network (ANN) using the backpropagation algorithm was proposed to estimate evapotranspiration as referred to pan evaporation. The meteorological data used in this study were obtained from Al-Zahra and Al-Zawia stations which located on the coastal area of western Libya lie. The input data were consisted of mean temperature, mean relative humidity and mean of actual sunshine hours of consecutive years (1995, 1996, 1997 and 1999). The performance of the ANN model was evaluated against a set of data that never seen by the model during the training phase. The evaluation of ANN model was also performed against Blaney and Criddle, Radiation and modified Penman methods. The results showed that ANN forecasts were superior to the ones obtained by Blaney and Criddle and Radiation methods. Due to its little input data, ANN is considered to be more efficient as compared with the modified Penman method. However, this application of ANN as a fitting tool should be useful in evapotranspiration modeling. Keywords: Evapotranspiration Pan evaporation, Artificial neural networks, Backpropagation algorithm.
Ahmed Ibrahim Ekhmaj(1-2012)

تم القيام بهذا البحث سنة (2006 ف) في معامل كلية الزراعة بجامعة الفاتح وذلك لدراسة مدى تأثير مسحوق نبات التين الشوكي (L) Mill Opuntia ficus-indica وقواعد أوراق النخيل المثمر (الكرناف) (L) Phoenix dactylifera في قدرة التربة الرملية على الاحتفاظ بالماء ، وذلك من حيث تأثيرها على سعة الاحتفاظ بالماء ( Water Holding Capacity) ومعامل التوصيل الهيدروليكي التشبعي Hydraulic Conductivity ) ) ، والمحتوي الرطوبي عند قيم شد مختلفة تم إضافة كل من مسحوق نبات التين الشوكي ، قواعد أوراق النخيل ( الكرناف ) و خليطهما إلى التربة الرملية بنسبة وزنيه 0 ، 2.5 ، 5 ، 7.5 % ، ولمقارنة النتائج تم إضافة محسن تجاري ( compost ) للتربة بالنسب المذكورة ، حيث بينت النتائج أن المواد المضافة أدت إلى زيادة سعة التربة بالاحتفاظ بالماء في جميع المعاملات فكانت الأفضلية لمعاملة خليط التين الشوكي والكرناف حيث سجلت 218.7 جم / كجم تربة في عينة الشاهد إلى 442.6 جم / كجم تربة عند نسبة 7.5 % في بداية التجربة و 423.8 جم / كجم تربة عند نهاية التجربة. كما بينت النتائج أن المواد المضافة أدت إلى انخفاض معامل التوصيل الهيدروليكي التشبعي للتربة الرملية في جميع المعاملات وكانت معاملة التين الشوكي أكثر انخفاضا، فقد تغير معامل التوصيل الهيدروليكي من 5 متر/ يوم عند نسبة إضافة 0% إلى 0.7 متر/ يوم عند نسبة إضافة 7.5%. في حين سجلت إضافة المحسنات زيادة في المحتوى الرطوبي لكل المعاملات عند قيم الشد 0.3، 1، 3، 15 بار. Abstract This experiment was conducted in 2006 at laboratories of the faculty of Agriculture, Alfateh university to investigate the impact of Indian fig "Opuntia ficus-indica" in powder form and date palm tree "Phoenix dactylifera leaf bases (Kurnaf) on water holding capacity, haydraulic conductivity, and water content at different tensions. Added materilas were mixed with sandy soil at 0, 2.5, 5 and 7.5% as treatments. To compare results, a commercial compost was added to the soil at the same percetages. Results showed that all treatments improved water holding capacity at all treatments, however, a mix of indian fig and palm tree base treatment was the highest at 7.5%, determined at 442.61 g/kg at the beginning of the experiment and 423.80 g/kg at its end, compared with the control which was 218.74 g/kg soiResults also showed added materials led to decrease in saturated hydraulic conductivity in all treatments, however, indian fig was the most effective, determined at 0.76 m/day at 7.5%, compared with 5.0 m/day for control. Last, all treatments showed increase in water contents at 0.3, 1, 3, and 15 bar tension.
المنتصر بالله مختار محمد القريقني (2010)

Lithospheric-derived resources such as soil texture and coarse fragments are key soil physical properties that contribute to ecosystem services (ES), which can be valued based on "soil" or "mineral" stocks. Soil survey data provides an inexpensive alternative to detailed field measurements which are often labor-intensive, time-consuming, and costly to obtain. However, both field and soil survey data contain heterogeneous information with a certain level of variability and uncertainty in data. This study compares the potential of using field measurements and information from the Soil Survey Geographic database (SSURGO) for coarse fragments (CF), sand (S), silt (Si), clay (C), and texture class (TC) in the surface soil (Ap horizon) for the 147-hectare Cornell University Willsboro Research Farm, NY. Maps were created based on following methods: (a) utilizing data from the SSURGO database for individual soil map unit (SMU) at the field site and using representative or reported values across individual SMU; (b) averaging the field data within a specific SMU boundary and using the averaged value across the SMU; and (c) interpolating field data within the farm boundaries based on the individual soil cores. This study demonstrates the important distinction between mapping using the "crisp" boundaries of SSURGO databases compared to the actual spatial heterogeneity of field interpolated data. Maps of CF, S, Si, C, and TC values derived from interpolated field core samples were dissimilar to maps derived by using averaged core results or SSURGO values over the SMUs. Dissimilarities in the maps of CF, S, Si, C, and TC can be attributed to several factors (e.g., official soil series data being collected from "type locations" outside of the study areas). Correlation plot of clay estimates for each SMU showed statistically significant correlations between SSURGO and field-averaged (r = 0.823, p = 0.003) and field-interpolated clay (r = 0.584, p = 0.028) estimates, but no correlation was found for CF, S, and Si. Ecosystem services provided by quantitative data such as CF, S, Si, and C may not be independent from each other and other soil properties. Key soil properties should also include categorical data, such as texture class, which is used for another key soil property-available soil water ratings. Current valuation of soil texture is often linked to specific mineral commodities, which does not always address the issue of soil based valuation including indirect use value. arabic 19 English 133
Elena Mikhailova, Christopher Post, Patrick Gerard, Mark Schlautman, Michael Cope, Garth Groshans, Roxanne Stiglitz, Hamdi Zurqani, John Galbraith(9-2019)