1Deming S.R., Johnson L., Lehnert D., Mutch D.R., Probyn L., Renner K., Smeenk J., Thalmann S., and Worthington L. 2007. Building a Sustainable Future: Ecologically Based Farming Systems. Extension Bulletin E-2983. Michigan State University, East Lansing, MI.
2Vandermeer J.H. 2011. The Ecology of Agroecosystems. Jones & Bartlett Publishers, Sudbury, MA. p. 387.
3Daily G.C., Matson P.A., and Vitousek P.M. 1997. Ecosystem services supplied by soil. In Daily G.C. (ed.). Nature's Services: Societal Dependence on Natural Ecosystems. Island Press, Washington, DC. p. 113–132.
4Stockdale E.A., Lampkin N.H., Hovi M., Keating R., Lennartsson E.K.M., Macdonald D.W., Padel S., Tattersall F.H., Wolfe M.S., and Watson C.A. 2001. Agronomic and environmental implications of organic farming systems. Advances in Agronomy 70:261–327.
5Liebig M.A. and Doran J.W. 1999. Impact of organic production practices on soil quality indicators. Journal of Environmental Quality 28:1601–1609.
6Altieri M.A. 2002. Agroecology: the science of natural resource management for poor farmers in marginal environments. Agriculture, Ecosystems and Environment 93:1–24.
7Andrews S.S., Karlen D.L., and Cambardella C.A. 2004. The soil management assessment framework: a quantitative soil quality evaluation method. Soil Science Society of America Journal 68:1945–1962.
8Doran J.W. and Zeiss M.R. 2000. Soil health and sustainability: managing the biotic component of soil quality. Applied Soil Ecology 15:3–11.
9van Bruggen A.H.C. and Semenov A.M. 2000. In search of biological indicators for soil health and disease suppression. Applied Soil Ecology 15:13–24.
10Karlen D.L., Mausbach M.J., Doran J.W., Cline R.G., Harris R.F., and Schuman G.E. 1997. Soil quality: a concept, definition, and framework for evaluation. Soil Science Society of America Journal 61:4–10.
11Stott D.E., Andrews S.S., Liebig M.A., Wienhold B.J., and Karlen D.L. 2010. Evaluation of β-glucosidase activity as a soil quality indicator for the soil management assessment framework. Soil Science Society of America Journal 74:107–119.
12Dick R.P., Breakwell D.P., and Turco R.F. 1996. Soil enzyme activities and biodiversity measurements as integrative microbiological indicators. In Doran J.W. and Jones A.J. (eds). Methods of Assessing Soil Quality. Soil Science Society of America Special Publication 49, Soil Science Society of America, Madison, WI. p. 247–271.
13Delate K. 2002. Using an agroecological approach to farming systems research. HortTechnology 12:345–354.
14Drinkwater L.E., Letourneau D.K., Worken F., van Bruggen A.H.C., and Shennan C. 1995. Fundamental differences between conventional and organic tomato agroecosystems in California. Ecological Applications 5:1098–1112.
15Scow K.M., Somasco O., Gunapala N., Lau S., Venette R., Ferris H., Miller R., and Shennan C. 1994. Transition from conventional to low-input agriculture changes soil fertility and biology. California Agriculture 48(5):20–26.
16Melero S., Madejon E., Herencia J.F., and Ruiz J.C. 2008. Effect of implementing organic farming on chemical and biochemical properties of an irrigated loam soil. Agronomy Journal 100:136–144.
17Wander M.M., Hedrick D.S., Kaufman D., Traina S.J., Stinner B.R., Kehrmeyer S.R., and White D.C. 1995. The functional significance of the microbial biomass in organic and conventionally managed soils. Plant and Soil 170:87–97.
18Mäder P., Fließbach A., Dubois D., Gunst L., Fried P., and Niggli U. 2002. Soil fertility and biodiversity in organic farming. Science 296:1694–1697.
19Arshad M.A. and Martin S. 2002. Identifying critical limits for soil quality indicators in agro-ecosystems. Agriculture, Ecosystems and Environment 88:153–160.
20Acosta-Martinez V., Zobeck T.M., Gill T.E., and Kennedy A.C. 2003. Enzyme activities and microbial community structure in semiarid agricultural soils. Biology and Fertility of Soils 38:216–227.
21Pritchett K., Kennedy A.C., and Cogger C.G. 2011. Management effects on soil quality in organic vegetable systems in western Washington. Soil Science Society of America Journal 75:605–615.
22Hezel L.F. and Kremer R.J. 2008. Healing and building soil on Prairie Birthday Farm. Missouri Prairie Journal 29(3):14–20.
23Nelson P.W. 2005. The Terrestrial Natural Communities of Missouri. Missouri Department of Conservation, Jefferson City, MO. p. 550.
24Preston G.D. 1986. Soil Survey of Clay and Ray Counties, Missouri. USDA Soil Conservation Service, US Government Printing Office, Washington, DC.
25Hoeft R.G., Nafzinger E.D., Johnson R.R., and Aldrich S.R. 2000. Modern Corn and Soybean Production. MCSP Publications, Champaign, IL.
26Nelson D.W. and Sommers L.E. 1996. Total carbon, organic carbon, and organic matter. In Sparks D.L. (ed.). Methods of Soil Analysis – Part 3: Chemical Methods. Soil Science Society of America, Madison, WI. p. 961–1010.
27Kemper W.D. and Rosenau R.C. 1986. Aggregate stability and size distribution. In Klute A. (ed.). Methods of Soil Analysis – Part 1: Physical Methods. Soil Science Society of America, Madison, WI. p. 425–442.
28Angers D.A. and Mehuys G.R. 1993. Aggregate stability to water. In Carter M.R. (ed.). Soil Sampling and Methods of Analysis. Canadian Society of Soil Science, Lewis Publishers, Boca Raton, FL. p. 651–657.
29Tabatabai M.A. 1994. Soil enzymes. In Weaver R.W. (ed.). Methods of Soil Analysis – Part 2: Biological and Biochemical Properties. Soil Science Society of America, Madison, WI. p. 777–823.
30Parham J.A. and Deng S.P. 2000. Detection, quantification and characterization of glucosaminidase activity in soil. Soil Biology and Biochemistry 32:1183–1190.
31Schnürer J. and Roswall T. 1982. Fluorescein diacetate hydrolysis as a measure of total microbial activity in soil and litter. Applied and Environmental Microbiology 43:1256–1261.
32Green V.S., Stott D.E., and Diack M. 2006. Assay for fluorescent diacetate hydrolytic activity: optimization for soil samples. Soil Biology and Biochemistry 38:693–701.
33Dick R.P. 1997. Soil enzyme activities as integrative indicators of soil health. In Pankhurst C.E., Doube B.M., and Gupta V.V.S.R. (eds). Biological Indicators of Soil Health. CAB International, Oxford, UK. p. 121–156.
34Acosta-Martinez V., Zobeck T.M., and Allen V.G. 2010. Soil microbial communities and function in alternative systems to continuous cotton. Soil Science Society of America Journal 74:1181–1192.
35Wolf B. and Snyder G.H. 2003. Sustainable Soils: The Place of Organic Matter in Sustaining Soils and Their Productivity. Food Products Press, Binghamton, NY. p. 352.
36Heckman J.R., Weil R. and Magdoff F. 2009. Practical steps to soil fertility for organic agriculture. In Francis C. (ed.). Ecology in Organic Farming Systems. Agronomy Monograph 54, American Society of Agronomy, Madison, WI. p. 139–172.
37Dick W.A. and Tabatabai M.A. 1992. Significant and potential uses of soil enzymes. In Metting F.B.Jr (ed.). Soil Microbial Ecology: Applications in Agricultural and Environmental Management. Marcel-Dekker, New York, p. 95–127.
38Acea M.J. and Carballa T. 1996. Microbial response to organic amendments in a forest soil. Bioresource Technology 57:193–199.
39Teasdale J.R., Coffman C.B., and Mangum R.W. 2007. Potential long-term benefits of no-tillage and organic cropping systems for grain production and soil improvement. Agronomy Journal 99:1297–1305.
40Kremer R.J. and Li J. 2003. Developing weed-suppressive soils through improved soil quality management. Soil & Tillage Research 72:193–202.
41Jastrow J.D. and Miller R.M. 1998. Soil aggregate stability and carbon sequestration: feedbacks through organomineral associations. In Lal R., Kimble J.M., Follett R.F., and Stewart B.A. (eds). Soil Processes and the Carbon Cycle. CRC Press, Boca Raton, FL. p. 207–223.
42Dick R.P. 1992. A review: long-term effects of agricultural systems on soil biochemical and microbial parameters. Agriculture, Ecosystems and Environment 40:25–36.
43Singer J.W., Franzluebbers A.F., and Karlen D.L. 2009. Grass-based farming systems: soil conservation and environmental quality. In Wedin W.F. and Fales S.L. (eds). Grassland: Quietness and Strength for a New American Agriculture. American Society of Agronomy, Madison, WI. p. 121–136.
44Bandick A.K. and Dick R.P. 1999. Field management effects on soil enzyme activities. Soil Biology & Biochemistry 31:1471–1479.
45Reeve J.R., Schadt C.W., Carpenter-Boggs L., Sanghoon K., Zhou J., and Reganold J.P. 2010. Effects of soil type and farm management on soil ecological functional genes and microbial activities. ISME Journal 4:1099–1107.
46Acosta-Martinez V., Cruz L., Sotomayor-Ramirez D., and Perez-Alegria L. 2007. Enzyme activities as affected by soil properties and land use in a tropical watershed. Applied Soil Eology 35:35–45.
47Ekenler M. and Tabatabai M.A. 2003. Tillage and residue management effects on β-glucosaminidase activity in soils. Soil Biology and Biochemistry 35:871–874.
48Udawatta R.P., Kremer R.J., Garrett H.E., and Anderson S.H. 2009. Soil enzyme activities and physical properties in a watershed managed under agroforestry and row-crop systems. Agriculture, Ecosystems and Environment 131:98–104.
49Fernandesa M.F., Barretoa A.C., Mendesb I.C., and Dick R.P. 2011. Short-term response of physical and chemical aspects of soil quality of a kaolinitic Kandiudalfs to agricultural practices and its association with microbiological variables. Agriculture, Ecosystems and Environment 142:419–427.
50Jordan D., Kremer R.J., Bergfield W.A., Kim K.Y., and Cacnio V.N. 1995. Evaluation of microbial methods as potential indicators of soil quality in historical agricultural fields. Biology and Fertility of Soils 19:297–302.
51Reganold J.P., Andrews P.K., Reeve J.R., Carpenter-Boggs L., Schadt C.W., Alldredge J.R., Ross C.F., Davies N.M., and Zhou J. 2011. Fruit and soil quality of organic and conventional strawberry agroecosystems. PLoS ONE 5(9):e12346. doi:10.1371/journal.pone.0012346.