Many soil regulating ecosystem services (ES) are linked to Earth’s atmosphere, but associated monetary values often are unknown or difficult to quantify. Atmospheric deposition of calcium (Ca2+) and magnesium (Mg2+) are abiotic flows (wet, dry, and total) from the atmosphere to land surfaces, which potentially can become available to sequester carbon (C) as soil inorganic carbon (SIC). However, these processes typically have not been included in economic valuations of ecosystem services. The primary objective of this study was to demonstrate an approach for valuing non-constrained potential SIC sequestration from atmospheric Ca2+ and Mg2+ deposition based on the concept of the avoided social cost of carbon dioxide emissions (SC-CO2). Maximum monetary values associated with the non-constrained potential SIC sequestration were compiled for the contiguous United States (U.S.) by soil order, land resource region (LRR), state, and region using available deposition data from the National Atmospheric Deposition Program (NRSP-3). For the entire contiguous U.S., an average annual monetary value for the non-constrained potential SIC sequestration due to atmospheric Ca2+ and Mg2+ deposition was $135M (i.e., $135 million U.S. dollars, where M = million = 106). Mollisols, Alfisols, and Entisols were soil orders with the highest average annual monetary values for non-constrained potential SIC sequestration. When normalized by land area, however, Vertisols had the highest average annual monetary values followed by Alfisols and Mollisols for non-constrained potential SIC sequestration. From a more agricultural perspective, the LRRs with the highest average annual monetary values for non-constrained potential SIC sequestration were the Western Range and Irrigated Region (D), the Central Feed Grains and Livestock Region (M), and the Central Great Plains Winter Wheat and Range Region (H). When normalized by area, the LRRS with the highest average annual monetary values were the Southwest Plateaus and Plains Range and Cotton Region (I) and the Florida Subtropical Fruit, Truck Crop and Range Region (U). Among the U.S. states, the highest average annual monetary values for non-constrained potential SIC sequestration were Texas, Kansas, and New Mexico, but when normalized by area the highest values by state were Kansas, Iowa, and Texas. Geographical regions in the contiguous U.S. with the highest average annual monetary values for non-constrained potential SIC sequestration were the South Central, Midwest, and West; when normalized by area, the highest values by region were South Central, Midwest, and Northern Plains. Constraints on maximum monetary values, based on physical, chemical, biological, economic, social, and political limitations, need to be considered and quantified to obtain more precise and accurate accounting of the ES associated with SIC sequestration due to atmospheric Ca2+ and Mg2+ deposition. arabic 14 English 112
Elena A. Mikhailova, Hamdi A. Zurqani, Christopher J. Post, Mark A. Schlautman(5-2020)

أجريت التجربة بمحطة أبحاث كلية الزراعة / جامعة طرابلس. لغرض فحص مدى تأثر حشيشة السعد (Cyperus rotundus L.) بتركيزات مختلفة من طحين أوراق أشجار السرول (Eucalyptus camaldulensis). وقد أجريت هذه الدراسة نتيجة لصعوبة مكافحة حشيشة السعد بسبب طبيعة دورة حياتها حيث تنتج الدرنة الواحدة عدة براعم، يتكون منها المجموع الخضري، وبالتالي يمكن إنتاج عدة نباتات من درنة واحدة. وكذلك مثابرة الدرنات وكمون البراعم وتكرار تجدد نمو المجموع الخضري من الدرنة الواحدة مما أدى إلى صعوبة مكافحتها طبيعيا، ومن ناحية المكافحة الكيماوية فهي تعتبر أيضا عملية غير مجدية لندرة المبيدات الاختيارية الفعالة في مكافحة السعد وبالتالي وباستخدام طحين اوراق اشجار السرول بينت النتائج انخفاض في طول المجموع الخضري وكذلك في طول المجموع الجذري ووزن النبات بزيادة تركيز طحين أوراق أشجار السرول، وهذا يعطي مؤشرا قويا إلى إمكانية مكافحة هذه الحشيشة بهذه الطريقة. كلمات مفتاحيه :- أشجار السرول - Eucalyptus camaldulensis ، حشيشة السعد - Cyperus rotundus L arabic 112 English 39
عمار عمران عبدالسلام الشمام, د. أحمد مراد القنوني(12-2011)

Abstract—The soil moisture content is an important property of the soil. The results of mean weekly gravimetric soil moisture content, measured for the three soil layers within the A horizon, showed that it was higher for the top 5 cm over the whole period of monitoring (15/7/2004 up to 10/11/05) with the variation becoming greater during winter time. This reflects the pattern of rainfall in Ireland which is spread over the whole year and shows that light rainfall events during summer time were compensated by loss through evapotranspiration, but only in the top 5 cm of soil. This layer had the highest porosity and highest moisture holding capacity due to the high content of organic matter. The gravimetric soil moisture contents of the top 5 cm and the underlying 5-15 and 15-25 cm layers show that bottom site of the Hill Field had higher soil moisture content than the middle and top sites during the whole period of monitoring. Keywords— Soil, Soil moisture, Gravimetric soil moisture content. arabic 7 English 39
ِAbdulfatah Faraj Abdullaha Aboufayed(1-2013)