B. M. Shrestha, B. R. Singh, B. R. Sitaula, R. Lal and R. M. Bajarcharya, “Soil Aggregate and Particle-Associated Organic Carbon under Different Land Uses in Nepal,” Soil Science Society of America Journal, Vol. 71, No. 4, 2007, pp. 94-1203. doi:10.2136/sssaj2006.0405
 R. Lal, “Soil Erosion and the Global Carbon Budget,” Environment International, Vol. 29, No. 4, 2003, pp. 437-450. doi:10.1016/S0160-4120(02)00192-7
 D. K. Benbi and J. S. Brar, “A 25-Year Record of Carbon Sequestration and Soil Properties in Intensive Agriculture,” Agronomy for Sustainable Development, Vol. 29, No. 2, 2009, pp. 257-265. doi:10.1051/agro:2008070
 K. R. Islam and R. R. Weil, “Land Use Effects on Soil Quality in a Tropical Forest Ecosystem of Bangladesh,” Agricultural Ecosystem and Environment, Vol. 79, No. 1, 2000, pp. 9-16. doi:10.1016/S0167-8809(99)00145-0
 R. V. Pouyat, I. D. Yesilonis, J. Russell-Anelli and N. K. Neerchal, “Soil Chemical and Physical Properties That Differentiate Urban Land-Use and Cover Types,” Soil Science Society of America Journal, Vol. 71, No. 3, 2007, pp. 1010-1019. doi:10.2136/sssaj2006.0164
 M. Lemenih, “Effects of Land Use Changes on Soil Quality and Native Flora Degradation and Restoration in the Highlands of Ethiopia. Implications for Sustainable Land Management,” Doctoral Thesis, Swedish University of Agricultural Sciences, Uppsala, 2004.
 J. Six, E. T. Elliott and K. Paustian. “Aggregate and Soil Organic Matter Dynamics under Conventional and No Tillage Systems,” Soil Science Society of America Journal, Vol. 63, No. 5, 1999, pp. 1350-1358.
 R. A. Houghton, J. L. Hacker and K. T. Lawrence, “The US Carbon Budget: Contributions from Land Use Change,” Science, Vol. 285, No. 5427, 1999, pp. 574-578.
 D. Solomon, F. Fritzsche, J. Lehmann, M. Tekalign and W. Zech, “Soil Organic Matter Dynamics in the Sub Humid Agro-Ecosystems of the Ethiopian Highlands: Evidence from Natural 13C Abundance and Particle-Size Fractionation,” Soil Science Society of America Journal, Vol. 66, No. 3, 2002, pp. 969-978.
 W. H. Schlesinger and J. A. Andrews, “Soil Respiration and the Global Carbon Cycle,” Biogeochemistry, Vol. 48, No. 7, 2000, pp. 7-20. doi:10.1023/A:1006247623877
 L. J. Osher, P. A. Matson and R. Amundson, “Effect of Land Use Change on Soil Carbon in Hawaii,” Biogeochemistry, Vol. 65, No. 2, 2003, pp. 213-232.
 F. Yimer, S. Ledin and A. Abdelkadir, “Soil Property Variations in Relation to Topographic Aspect and Vegetation Community in the South-Eastern Highlands of Ethiopia,” Forest Ecology and Management, Vol. 232, No. 1-3, 2006, pp. 90-99.
 M. Lemenih, E. Karltun and M. Olsson, “Soil Organic Matter Dynamics after Deforestation along a Farm Field Chronosequence in Southern Highlands of Ethiopia,” Agroecosystems and Environment, Vol. 109, No. 1-2, 2005, pp. 9-19. doi:10.1016/j.agee.2005.02.015
 Mengistu A. “Country Pasture/Forage Resource Profiles”. FAO, 2006.
 M. Abebe, “Nature and Management of Ethiopian Soils,” Alemaya University of Agriculture, Dire Dawa, 1998.
 N. Brady and R. R. Weil, “The Nature and Properties of Soils,” 14th Edition, Prentice Hall Inc., Lebanon, 2008.
 G. Abera, E. Wolde-meskel and L. R. Bakken, “Carbon and Nitrogen Mineralization Dynamics in Different Soils of the Tropics Amended with Legume Residues and Contrasting Soil Moisture Contents,” Biology and Fertility of Soils, Vol. 48, No. 1, 2012, pp. 51-66.
 G. Abera, E. Wolde-Meskel, S. Beyene and L. R. Bakken. “Nitrogen Mineralization Dynamics under Different Moisture Regimes in Tropical Soils,” International Journal of Soil Science, Vol. 7, No. 4, 2012, pp. 132-145.
 EARO, “Major Agroecological Zones of Ethiopia,” Ethiopian Agricultural Research Organization, Addis Ababa, 1998.
 T. H. Borresen, “Soil Physics Field and Laboratory Me thuds,” Agricultural University of Norway, Norway, 2003 (Unpublished).
 S. Saggar, R. M. Andrew, K. R. Tate, C. B. Hedley, N. J. Rodda and J. A. Townsend, “Modeling Nitrous Oxide Emissions From New Zealand Dairy Grazed Pastures,” Nutrient Cycling in Agroecosystems, Vol. 68, No. 3, 2004, pp. 243-255. doi:10.1023/B:FRES.0000019463.92440.a3
 P. R. Day, “Particle Fractionation and Particle-Size Analysis,” In: C. A. Black, Ed., Methods of Soil Analysis, American Society of Agronomy Inc., Madison, 1965, pp. 545-567.
 D. W. Nelson and L. E. Sommers, “Total Carbon, Organic Carbon and Organic Matter,” In: A. L. Page, Ed., Methods of Soil Analysis, American Society of Agronomy Inc., American Society of Soil Science Inc., Madison, 1982, pp. 539-580.
 J. M. Bremner and C. S. Mulvaney, “Nitrogen-Total,” In: A.L. Page, Methods of Soil Analysis, American Society of Agronomy Inc., American Society of Soil Science Inc., Madison, 1982, pp. 595-624.
 S. R. Olsen and L. E. Sommers, “Phosphorous,” In: A.L. Page, Ed., Methods of Soil Analysis, American Society of Agronomy Inc., American Society of Soil Science Inc., Madison, 1982, pp. 403-430.
 H. D. Chapman, “Cation Exchange Capacity,” In: C.A. Black, Ed., Methods of Soil Analysis-Chemical and Microbiological Properties. Agronomy, American Society of Agronomy Inc., Madison, Vol. 9, 1965, pp. 891-901.
 W. L. Lindsay and W. A. Norvell, “Development of a DTPA Soil Test for Zinc, Iron, Manganese, and Copper,” Soil Science Society of America Journal, Vol. 42, No. 3, 1978, pp. 421-428.
 M. T. Olsson, M. Erlandsson, L. Ludin, T. Nilsson, Å. Nilsson and J. Stendah, “Organic Carbon Stocks in Swedish Podzol Soils in Relation to Soil Hydrology and Other Site Characteristics,” Silva Fennica, Vol. 43, No. 2, 2009, pp. 209-222.
 L. Molstad, P. Dorsch and L. R. Bakken, “Robotized Incubation Systems for Monitoring Gases (O2, NO, N2O, N2) in Denitrifying Cultures,” Journal of Microbiological Methods, Vol. 71, No. 3, 2007, pp. 202-211.
 H. Van de Werf and W. Verstrate, “Estimation of Active Microbial Biomass by Mathematical Analysis of Respiration Curves: Relation to Conventional Estimation of Total Biomass,” Soil Biology and Biochemistry, Vol. 19, No. 3, 1987, pp. 267-271. doi:10.1016/0038-0717(87)90008-3
 T. H. Anderson and K. H. Domsch, “Application of Eco-Physiological Quotients (qCO2 and qD) on Microbial Biomass from Soils of Different Cropping histories,” Soil Biology and Biochemistry, Vol. 25, No. 3, 1990, pp. 393-395. doi:10.1016/0038-0717(93)90140-7
 E. D. Vance, P. C. Brookes and D. S. Jenkinson, “An Extraction Method for Determining Soil Microbial Bio mass C,” Soil Biology and Biochemistry, Vol. 19, No. 6, 1987, pp. 703-707. doi:10.1016/0038-0717(87)90052-6
 P. C. Brookes, A. Landman, G. Pruden and D. S. Jenkin son, “Chloroform Fumigation and the Release of Soil Nitrogen: A Rapid Direct Extraction Method to Measure Microbial Biomass Nitrogen in Soil,” Soil Biology and Biochemistry, Vol. 17, No. 6, 1985, pp. 837-842.
 R. C. Barreto, E. M. Beata, E. L. M. John, L. O. A. M. Pedro, T. Eleno, F. Julio and R. C. Adriana, “The Impact of Soil Management on Aggregation, Carbon Stabilization and Carbon Loss as CO2 in the Surface Layer of A Rhogic Ferralsol in Southern Brazil,” Agricultural Eco system and Environment, Vol. 132, No. 3-4, 2009, pp. 243-251. doi:10.1016/j.agee.2009.04.008
 Range Land Soil Quality.
 W. Tena and S. Beyene, “Identification of Growth Limiting Nutrients (s) in Alfisols: Soil Physico-Chemical Properties, Nutrient Contents and Biomass Yield of Maize,” American Journal of Plant Nutrition and Fertilizer Technology, Vol. 1, No. 1, 2011, pp. 23-35.
 S. W. Buol, R. J. Southard, R. C. Graham and P. A. Mc Danie, “Soil Genesis and Classification,” 5th Edition, Iowa State Press, 2003.
 J. Hassink, “Effect of Soil Texture on the Size of Microbial Biomass and the Amount of C and N Mineralized Per Unit of Microbial Biomass in Dutch Grassland Soils,” Biochemistry, Vol. 26, No. 11, 1994, pp. 1573-1581.
 R. H. Azooz, M. A. Arshad and A. J. Franzlubbers, “Pore Size Distribution and Hydraulic Conductivity Affected by Tillage in Northwestern Canada,” Soil Science Society of America Journal, Vol. 60, No. 4, 1996, pp. 1197-1201.
 K. E. Dobbie and K. A. Smith, “The Effect of Temperature, Water-Filled Pore Space, and Land Use on N2O Emissions from an Imperfectly Drained Gleysol,” European Journal of Soil Science, Vol. 52, No. 4, 2001, pp. 667-673. doi:10.1046/j.1365-2389.2001.00395.x
 S. Saggar, G. W. Yeates and T. G. Shepherd, “Cultivation Effects on Soil Biological Properties, Microfauna and Organic Matter Dynamics in Eutric Gleysol and Gleyic Luvisol Soils in New Zealand,” Soil Tillage Research, Vol. 58, No. 1, 2001, pp. 55-68.
 A. Demessie, B. R. Singh, R. Lal and T. Borresen, “Effect of Eucalyptus and Coniferous Plantations on Soil Properties in Gambo District, Southern Ethiopia,” Acta Agrictulturae Scandinavia Section B—Soil and Plant Science, Vol. 62, No. 5, 2012, pp. 455-466.
 G. Abera, “Carbon and Nitrogen Transformations under Drought Stress: Implications for Nitrogen Delivery to Non Leguminous Crops in Seasonally Dry Tropical Climate,” Ph.D. Thesis, Norwegian University of Life Science, Nor way, 2012.
 R. Dalal and K. Y. Chan, “Soil Organic Matter in Rained Cropping Systems of Australian Cereal Belt,” Australian Journal of Soil Research, Vol. 39, No. 3, 2001, pp. 435-464. doi:10.1071/SR99042
 J. Balesdent, E. Besnard, D. Arrouays and C. Chenu. “Dynamics of Organic Matter in Particle Size Fractions in a Forest-Cultivation Sequence,” Plant Soil, Vol. 201, No. 1, 1998, pp. 49-57. doi:10.1023/A:1004337314970
 B. T. Christensen, “Carbon in Primary and Secondary Organomineral Complexes,” In: M. R. Carter and B. A. Stewart, Eds., Structure and Organic Matter Storage in Agricultural Soils, CRC Press, Inc., Boca, Raton, 1996, pp. 97-165.
 J. A. Baldock and J. O. Skjemstad, “Role of the Soil Matrix and Minerals in Protecting Natural Organic Materials Against Biological Attack,” Organic Geochemistry, Vol. 31, No. 7, 2000, pp. 697-710.
 W. Nazif, S. Perveen and I. Saleem, “Status of Micronutrients in Soils of District Bhimber (Azad Jammu and Kashmir),” Journal of Agriculture and Biological Science, Vol. 1, No. 1, 2006, pp. 35-40.
 T. Chibsa and A. Ta’, “Assessment of Soil Organic Matter under Four Land Use Systems in the Major Soils of Bale Highlands, South East Ethiopia. B. Factors affecting Soil Organic Matter Distribution,” World Journal of Agricultural Science, Vol. 6, No. 11, 2009, pp. 1506-1512.
 R. L. Parfitt, B. K. G. Thng, J. S. Whitton and T. G. Sheperd, “Effects of Clay Minerals and Land Use on Organic Matter Pools,” Soil Science Society of America Journal, Vol. 48, No. 1-2, 1997, pp. 305-311.
 D. Jonathan, “Nitrogen Mineralization Potential in Important Agricultural Soils of Hawaii,” Soil and Crop Management, 2006.
 D. Dimoyiannis, “Wet Aggregate Stability as Affected by Excess Carbonate and Other Soil Properties,” Land De gradation and Develeomepnt, Vol. 23, No. 5, 2012, pp. 450-455. doi:10.1002/ldr.1085
 M. E. Reginald, A. Rajkumar, G. Joshy, R. C. Lal and S. A. Vetrivel, “Soil Biological and Biochemical Response to Cd Exposure,” Open Journal of Soil Science, Vol. 1, No. 1, 2011, pp. 8-15. doi:10.4236/ojss.2011.11002