1.Acton, D.F., and Gregorich, L.J. 1995. The health of our soils - towards sustainable agriculture in Canada. Centre for Land and Biological Resources Research, Research Branch, Agriculture and Agri-Food Canada, Ottawa, Ont. 138p.
2.Alef, K., and Nannipieri, P. 1995. Methods in Applied Soil Microbiological and Biochemistry. Academic Press INC. 576p.
3.Al-Kaisi, M.M., Yin, X.H., and Licht, M.A. 2005. Soil carbon and nitrogen changes as influenced by tillage and cropping systems in some Iowa soils. Agriculture, Ecosystems and Environment. 105: 635-647.
4.Andrews, S., Karlen, D., and Mitchell, J. 2002. A comparison of soil quality indexing methods for vegetable production systems in Northern California. Agriculture, Ecosystems and Environment. 90: 25-45.
5.Andrews, S.S., and Carroll, C.R. 2001. Designing a soil quality assessment tool for sustainable agroecosystem management. Ecological Applications. 11: 1573-1585.
6.Aparicio, V., and Costa, J.L. 2007. Soil quality indicators under continuous cropping systems in the Argentinean pampas. Soil and Tillage Research. 96: 155-165.
7.Armenise, E., Redmile-Godon, M.A., Stellaci, W.M., Ciccarese, A., and Rubino, P. 2013. Developing a soil quality index to compare soil fitness for agricultural use under different managements in the Mediterranean environment. Soil and Tillage Research. 130: 91-98.
8.Boluda, R., Roca-Pérez, L., Iranzo, M., Gil, C., and Mormeneo, S., 2014. Determination of enzymatic activities using a miniaturized system as a rapid method to assess soil quality. Europ. J. Soil Sci. 65: 2. 286-294.
9.Bonanomi, G., D'Ascoli, R., Antignani, V., Capodilupo, M., Cozzolino, L., Marzaiooli, R., Puopolo, G., Rutigliano, F.A., Scelza, R., Scotti, R., Rao, M.A., and Zoina, A. 2011. Assessing soil quality under intensive cultivation and tree orchards in Southern Italy. Applied Soil Ecology. 47: 3. 184-194.
10.Borůvka, L., Mládková, L., Drábek, O., and Vašát, R. 2007. Forest soil acidification assessment using principal component analysis and geostatistics. Geoderma. 140: 4. 374-382.
11.Cattell, R.B. 1966. The Scree test for the number of factors. Multivariate Behavioral Research. 1: 245-276.
12.Cherubin, M.R., Karlen, D.L., Cerri, C.E.P., Franco, A.L.C., Tormena, C.A., Davies, C.A., and Cerri, C.C. 2016. Soil quality indexing strategies for evaluating sugarcane expansion in Brazil. PLoS ONE. 11: 3. 1-26.
13.D'Hose, T., Cougnon, M., Vliegher, A.D., Vandecasteele, B., Viaene, N., Cornelis, W., Bockstaele, E.V., and Reheul, D. 2014. The positive relationship between soil quality and crop production: a case study on the effect of farm compost application. Applied Soil Ecology. 75: 189-198.
14.Doran, J.W., and Jones, A.J. 1996. Methods for Assessing Soil Quality. Soil Science Society of America Special Publication, vol. 49. Soil Science Society of America, Madison, WI. 401p.
15.Finkenbein, P., Kretschmer, K., Kula, K., Klotz, S., and Heilmeier, H. 2013. Soil enzyme activities as bioindicators for substrate quality in revegetation of a subtropical coal mining dump. Soil Biology and Biochemistry. 56: 87-89.
16.Fu, W.J., Tunney, H., and Zhang, C.S. 2010. Spatial variation of soil nutrients in a dairy farm and its implications for site-specific fertilizer application. Soil Tillage Research. 106: 185-193.
17.Gee, G.W., and Bauder, J.M. 1986. Particle-size analysis. P 383-411, In: A., Klute (ed.). Methods of Soil Analysis. Part 1: Physical and Mineralogical Methods. American Society of Agronomy. Soil Science Society of America, Madison, WI.
18.Guo, L., Sun, Z., Ouyang, Z., Han, D., and Li, F. 2017. A comparison of soil quality evaluation methods for Fluvisol along the lower Yellow River. Catena. 152: 135-143.
19.Haynes, R.J. 2005. Labile organic matter fractions as central components of the quality of agricultural soils: an overview Advances in Agronomy. 85: 221-268.
20.Hesse, P.R. 1971. A text book of soil chemical analysis. John Murray. London. 556p.
21.Kaiser, H.F. 1960. The application of electronic computers to factor analysis. Educational and Psychological Measurement. 20: 141-151.
22.Karlen, D.L., Andrews, S.S., and Doran, J.W. 2008. Soil quality: Current concepts and applications. Advances in Agronomy. 74: 1-40.
23.Kemper, W.D., and Rosenau, R.C. 1986. Aggregate stability and size distribution. P 425-442, In: A., Klute (ed.). Methods of Soil Analysis. Part 1: Physical and Mineralogical Methods. American Society of Agronomy. Soil Science Society of America, Madison, WI.
24.Knudsen, D., Peterson, G.A., and Pratt, P.F. 1982. Lithium, sodium and potassium. P 225-246, In: A.L.
Page (ed.) Methods of Soil Analysis. Part 2. America Society of Agronomy. Madison, WI.
25.Li, P., Zhang, T.L., Wang, X.X., and Yu, D.S. 2013. Development of biological soil quality indicator system for subtropical China. Soil Tillage Research. 126: 112-118.
26.Lima, A.C., Brussaard, L., Totola, M.R., Hoogmoed, W.B., and De Goede, R.G. 2013. A functional evaluation of three indicator sets for assessing soil quality. Applied Soil Ecology. 64: 194-200.
27.Lindsay, W.L., and Norvell, W.A. 1978. Development of a DTPA soil test for Zinc, Iron, Manganese and Copper. Soil Sci. Soc. Amer. J. 42: 3. 421-428.
28.Liu, Z., Zhou, W., Shen, J., He, P., Lei, Q., and Liang, G. 2014. A simple assessment on spatial variability of rice yield and selected soil chemical properties of paddy fields south China. Geoderma. 235-236: 39-47.
29.Liu, Z., Zhou, W., Li, S., He, P., Liang, G., Lv, J., and Jin, H. 2015. Assessing soil quality of gleyed paddy soils with different productivities in subtropical China. Catena. 133: 293-302.
30.Masto, R., Chhonkar, P., Singh, D., and Patra, A. 2008. Alternative soil quality indices for evaluating the effect of intensive cropping, fertilization and managing for 31 years in the semi-arid soils of India. Environmental Monitoring and Assessment. 136: 419-435.
31.Mukherjee, A., and Lal, R. 2014. Comparison of Soil Quality Index Using Three Methods. PLoS ONE. 9: 8. 1-15.
32.Norman, G.R., and Streiner, D.L. 2008. Biostatistics: The Bare Essentials. People’s Medical Publishing House, Shelton, CT. 200p.
33.Olsen, S.R., Cole, C.V., Watanabe, F.S., and Dean, L.A. 1954. Estimation of Available Phosphorous in Soils by Extraction with Sodium Bicarbonate; U.S. Department of Agriculture: Washington, D.C., USDA Circ. 939p.
34.Page, A.L., Miller, R.H., and Keeney, D.R. 1982. Methods of Soil Analysis, part 2, chemical and microbiological properties. American Society of Agronomy, Inc. Soil Science Society of America, Madison, WI.
35.Qi, Y., Darilek, J.L., Huang, B., Zhao, Y., Sun, W., and Gu, Z. 2009. Evaluating soil quality indices in an agricultural region of Jiangsu Province, China. Geoderma. 149: 325-334.
36.Ranjbar, A., Emami, H., Khorasani, R., and Karimi, Karoyeh, A.R. 2016. Soil Quality Assessments in Some Iranian Saffron Fields. J. Agric. Sci. Technol. 18: 3. 865-878.
37.Ray, SK., Bahttacharyya, T., Reddy, K.R., Pal, D.K., Tiwary, P., Mandal, D.K., Mandal, C., Prasad, J., Sarkar, D., and Venugopalan, M.V. 2014. Soil
and land quality indicators of the Indo-Gangetic plains of India. Curriculum. Science. 107: 1470-1486.
38.Reynolds, W.D., Drury, C.F., Tan, C.S., Fox, C.A., and Yang, X.M. 2009. Use of indicators and pore volume function characteristics to quantify soil physical quality. Geoderma. 152: 252-263.
39.Shahab, H., Emami, H., Haghnia, Gh., and Karimi, A. 2011. Determining most important properties for soil quality indices of agriculture and range lands in a some parts of southern Mashhad. J. Water Soil. 25: 5. 1197-1205.
40.Shukla, M.K., Lal, R., and Ebinger, M. 2006. Determining soil quality indicators by factor analysis. Soil and Tillage Research. 87: 194-204.
41.Sun, B., Zhou, S.L., and Zhao, Q.G. 2003. Evaluation of spatial and temporal changes of soil quality based on geostatistical analysis in the hill region of subtropical China. Geoderma. 115: 85-99.
42.Torbert, H.A., Krueger, E., and Kurtene, D. 2008. Soil quality assessment using fuzzy modeling. International Agrophysics. 22: 365-370.
43.Vasu, D., Singh, S., Ray, S., Tiwary, P., Chandran, P., Nimkar, A., and Anantular, S. 2016. Soil Quality index (SQI) as a tool to evaluate crop productivity in semi-arid Deecan plateau, India. Geoderma. 282: 70-79.
44.Walkley, A., and Black, I.A. 1934. An examination of Degtjareff method for determining soil organic matter and a proposed modification of the chromic acid titration method. Soil Science. 37: 29-37.
45.Yanbing, Q., Darilek, J.L., Biao, H., Yongcun, Z., Sun, W., and Gu, Z. 2009. Evaluating soil quality indices in an agricultural region of Jiangsu Province, China. Geoderma. 149: 325-334.
46.Zhang, X.Y., Sui, Y.Y., Zhang, X.D., Meng, K., and Herbert, S.J. 2007. Spatial variability of nutrient properties in black soil of northeast China. Pedosphere. 17: 1. 19-29.