Many attempts have been created to determine wetting pattern under trickle irrigation using sophisticated mathematical and numerical models, required detailed information concerning soil physical properties and too complicated for routine use. For this reason, an alternative methodology is proposed, which combines artificial neural networks (ANNs), laboratory and field experiments. The model input parameters were saturated hydraulic conductivity, application rate, volume of water applied and average change of moisture content. The model outputs were surface wetted radius and vertical advance of wetting front. A total of 280 and 100 vectors were used to train the ANNs model for surface wetted radius and vertical advance of wetting front estimations, respectively. To test the ANNs model, a total of 132 and 76 vectors were selected in case of surface wetted radius and vertical advance of wetting front estimations, respectively. Results of the test show that the surface wetted radius and vertical advance of wetting front can be predicted with a determination coefficient (r2 ) of 0.80 and 0.81 for the surface wetted radius and vertical advance of wetting front, respectively. Additionally, the ANNs approach was found to produce equally or more accurate descriptions of wetting pattern as compared to several analytical and empirical models which suggested for point source trickle irrigation design.
Ahmed Ibrahim Ekhmaj, A.M. ABDULAZI, A.M.ALMDNY(1-2007)

أجريت هذه الدراسة في مشروع أبو شيبة الزراعي والذي يقع جنوب غرب مدينة طرابلس بحوالي (60 كم)، خلال السنوات (2008 / 2009) م، وذلك بهدف تقييم إدارة المشروع والتي تتضمن: دراسة مصادر المياه ومدي ملائمتها للتركيبة المحصولية وذلك عن طريق التقييم الكمي والنوعي للمياه لتحقيق هذا الهدف تم إتباع الخطوات التالية : دراسة الأسس النظرية والمفاهيم المتعلقة بتلك الدراسة مثل ؛ نوعية المياه ، مصادر المياه الجوفية وتلوثها ، بعض التعريفات الأخرى ذات العلاقة ؛ دراسة الخصائص الهيدروجيولوجية لمنطقة الدراسة وتحديد الخزان الجوفي المستغل الذي يغذي الآبار في المشروع وعلاقته بالخزانات المجاورة ؛ تحديد مستوى منسوب المياه الجوفية ومقدار الهبوط فيه منذ إنشاء المشروع سنة 1982 م ؛ دراسة نوعية المياه من خلال تحليل 21 عينة مياه مأخوذة من آبار المشروع ؛ تقدير الاحتياجات المائية للمحاصيل المزروعة في المشروع وتحليل البيانات الحقلية والتاريخية التي تم تسجيلها في فترات سابقة وذلك باستخدام: المخططات البيانية والبرمجيات مثل ؛ مخطط مختبر الملوحة الأمريكي ، مثلث بايبر ، برنامج SERVER وبرنامج CROPWAT وبرنامج ROCKWORK لتوضيح التغيرات والتذبذبات في العوامل التالية ؛ نوعية المياه ، منسوب سطح المياه الجوفية و حركة المياه الجوفية ، من خلال هذه الدراسة يمكن استخلاص النتائج التالية : وصل الهبوط في منسوب المياه الجوفية منذ إنشاء المشروع إلي (57) متر بمعدل ( 2.1 متر/ السنة ) ، مما يشير إلي إن المياه المستغلة في الري أكثر بكثير من التغذية الطبيعية للخزان الجوفي ، كذلك هذا ينذر بخطر نضوب الخزان الجوفي ونتيجة لذلك جفت بعض الآبار ؛ كفاءة استعمال المياه في المشروع تتراوح فيما بين (69.2 %) و(78.9%) وذلك يشير إلي أن أكثر من (20 %) من المياه المستعملة تهدر دون أي فائدة ؛ ووفقاَ إلى التحاليل الكيميائية فإن نوعية المياه لازالت ملائمة لزراعة بعض المحاصيل التي تتحمل مستويات من الملوحة في المياه ، علي الرغم من أنها قد تغيرت قيمتها عما كانت عليه عند إنشاء المشروع ؛ تعد هذه المياه غير صالحة للشرب حسب دليل منظمة الصحة العالمية علي الرغم من أنه تم تزويد المشروع خلال السنوات الأخيرة بمياه النهر الصناعي لتغطية العجز في المياه ، وتحسين نوعية المياه ، ولكن المشكلة لم تحل بالكامل ، ونستخلص في النهاية أن المشروع يحتاج إلي سياسة مائية تأخذ في الاعتبار نظام الري والمحاصيل المزروعة . Abstract This study was conducted in ABSHEIBA agricultural project that located around 6o Km south west of Tripoli during the year 2008 / 2009. The goal of this study was to investigate the project management that includes determination of water resource and its suitability to the cropping combination according to water quality and quantity available. To achieve that goal, the following steps have been done : investigating the basic theoretical concepts that related to the study such as water quality, sources of groundwater contamination and other related definitions; investigating the hydro-geologic characteristics of the study area and determining the aquifer which recharging the wells in the project and its relationship with neighborhood aquifers; determining the water table level and its drawdown since constructing the project in 1982; investigating water quality through samples collected from 21 wells in the project; determining the water crop requirements for crops that have been cultivated in the project; and analyzing the field and historical data using charts and softwares such as American salinity diagram, Piper triangle, SERVER, CROPWAT, ROCKWORK to flare out the changes and fluctuation of related parameters such as water quality, water table surface, and groundwater movement From this study the following conclusions can be drawn out. The drawdown in water table since constructing the project reached 57 m with an average 2.1 m per year, which means that the extracted water for irrigation is much more than the recharged water of the aquifer. Also, this means the aquifer is mining and because of that some of the wells are already dried. The water use efficiency in project ranges from 78.9% to 69.2% that indicates more than 20% of the water used is lost without any benefit. According to chemical analysis, water quality still be suitable for some crops that tolerate salinity even though, it has been changed from the previous one during the project construction. Also, this water is not suitable for drinking according to World Health Organization. Even though, the project has been supplied during the last years by the water from the artificial river project to overcome the water deficit and improve the water quality but the problem does not solved completely. As the final conclusion, the project needs new policy concerning the irrigation system and cultivated crops.
رمضان الدوكالي عبد الحميد العلاقي (2012)

A “soil carbon hotspot” (SCH) is a geographic area having an abundance of soil carbon, and therefore higher ecosystem services value based on avoided social costs of CO2 emissions. Soil organic carbon (SOC), soil inorganic carbon (SIC), and total soil carbon (TSC) are critical data to help identify SCH at the farm scale, but monetary methods of hotspot evaluation are not well defined. This study provides a first of its kind quantitative example of farm-scale monetary value of soil carbon (C), and mapping of SCH based on avoided social cost of CO2 emissions using both Soil Survey Geographic (SSURGO) database and field measurements. The total calculated monetary value for TSC storage at the Willsboro Farm based on the SSURGO database was about 7.3 million U.S. dollars ($7.3 M), compared to $2.8 M based on field data from averaged soil core results. This difference is attributed to variation in soil sampling methodology, laboratory methods of soil C analyses, and depth of reported soil C results. Despite differences in total monetary valuation, observed trends by soil order were often similar for SSURGO versus field methods, with Alfisols typically having the highest total and area-normalized monetary values for SOC, SIC, and TSC. Farm-scale C accounting provides a more detailed spatial resolution of monetary values and SCH, compared to estimates based on country-level reports in soil survey databases. Delineation and mapping of SCH at the farm scale can be useful tools to define land management zones, to achieve social profit for farmers, and to realize United Nations (UN) Sustainable Development Goals (SDGs) based on avoided social cost of CO2 emissions. arabic 24 English 105
Elena Mikhailova, Christopher Post, Mark Schlautman, Gregory Post, Hamdi Zurqani(1-2020)