128 Soil Quality Institute (SQI). (1996). The soil quality concept. Edited by Soil Quality Institute. USDA‐NRCS.
129 Soil Quality Institute (SQI). (2003). Interpreting the soil conditioning index: A tool for measuring soil organic matter trends. Soil Quality – Agronomy Technical Note No. 16. Auburn, AL: Soil Quality Institute. https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_053273.pdf (verified 6‐12‐2020)
130 Sojka, R. E., and Upchurch, D. R. (1999). Reservations regarding the soil quality concept. Soil Science Society of America Journal 63, 1039–1054.
131 Sojka, R. E., Upchurch, D. R., and Borlaug, N. E. (2003). Quality soil management or soil quality management: Performance vs semantics. Advances in Agronomy 79, 1–68.
132 Sparling, G. P., Wheeler, D., Vesely, E.‐T., and Schipper, L. A. (2006). What is soil organic matter worth? Journal of Environmental Quality 35, 548–557.
133 Stott, 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 (SMAF). Soil Science Society America Journal 74, 107–119.
134 Stott, D. E., Cambardella, C. A., Wolf, R., Tomer, M. D., and Karlen, D. L. (2011). A soil quality assessment within the Iowa River south fork watershed. Soil Science Society America Journal 75, 2271–2282.
135 Van Bavel, C. H. M., and Schaller, F. W. (1950). Soil aggregation, organic matter and yields in a long‐time experiment as affected by crop management. Soil Science Society of America Proceedings 15, 399–408.
136 Van Doren, C. A., and Klingebiel, A. A. (1952). Effect of management on soil permeability. Soil Science Society of America Journal 16, 66–69.
137 Veum, K. S., Kremer, R. J., Sudduth, K. A., Kitchen, N. R., Lerch, R. N., Baffaut, C., Stott, D. E., Karlen, D. L., and Sadler, E. J. (2015). Conservation effects on soil quality indicators in the Missouri Salt River Basin. Journal of Soil and Water Conservation 70, 232–246.
138 Voorhees, W. B., Senst, C. G., and Nelson, W. W. (1978). Compaction and soil structure modification by wheel traffic in the northern Com Belt. Soil Science Society of America Journal 42, 344–349.
139 Voorhees, W. B. (1979). Soil tilth deterioration under row cropping in the northern Corn Belt: Influence of tillage and wheel traffic. Journal of Soil and Water Conservation 34, 184–186.
140 Voorhees, W. B. (1983). Relative effectiveness of tillage and natural forces in alleviating wheel‐induced soil compaction. Soil Science Society of America Journal 47, 129–133.
141 Voorhees, W. B., and Lindstrom, M. J. (1984). Long‐term effects of tillage method on soil tilth independent of wheel traffic compaction. Soil Science Society of America Journal 48, 152–156.
142 Waksman, S. A., and Starkey, R. L. (1924). Microbiological analysis of soil as an index of soil fertility: VII. Carbon dioxide evolution. Soil Science 17, 141–162.
143 Waksman, S. A., and Hutchings, I. J. (1935). The role of plant constituents in the preservation of nitrogen in the soil. Soil Science 40, 487–497
144 Wardle, D. A. (1994). Statistical analyses of soil quality. Science 264, 281–282.
145 Warkentin, B. P., and Fletcher, H. F. (1977). Soil quality for intensive agriculture. In Proceedings of the International Seminar on Soil Environment and Fertilizer Management in Intensive Agriculture (pp. 594–598). Japan: Society of Science of Soil and Manure.
146 Warkentin, B. P. (1992). Soil science for environmental quality – How do we know what we know? Journal of Environmental Quality 21, 163–166.
147 Warkentin, B. P. (1995). The changing concept of soil quality. Journal of Soil and Water Conservation 50 226–228.
148 Warkentin, B. P. (2008). Soil structure: A history from tilth to habitat. Advances in Agronomy 97, 239–272.
149 Whiteside, E. P., and Smith, R. S. (1941). Soil changes associated with tillage and cropping in humid areas of the United States. Agronomy Journal 33, 765–777.
150 Wienhold, B. J., Karlen, D. L., Andrews, S. S., and Stott, D. E. (2009). Protocol for indicator scoring in the Soil Management Assessment Framework (SMAF). Renewable Agriculture Food Systems 24, 260–266.
151 Wilson, H. A., and Browning, G. M. (1945). Soil aggregation, yields, runoff and erosion as affected by cropping systems. Soil Science Society of America Proceedings 10, 51–57.
152 Yoder, R. E. (1937). The significance of soil structure in relation to the tilth problem. Soil Science Society of America Proceedings 2, 21–33.
153 Young, C. E., and Osborn, C. T. (1990). Costs and benefits of the conservation reserve program. Journal of Soil and Water Conservation 45, 370–373.
154 Zobeck, T. M., Steiner, J. L., Stott, D. E., Duke, S. E., Starks, P. J., Moriasi, D. N., and Karlen, D. L. (2015). Soil quality index comparisons using Fort Cobb, Oklahoma, watershed‐scale land management data. Soil Science Society of America Journal 79, 224–238.
3 The Utility and Futility of Soil Health Assessment
John F. Obrycki and Lumarie Pérez‐Guzmán
Chapter Overview
Documenting benefits from soil health management practices and assessments has been described as both useful and futile because it requires continual observation, some form of data collection, and an assessment protocol. This chapter focuses on the benefits of soil health being evaluated through soil physical, chemical, and biological property measurements. A producer, landowner, or researcher interested in soil health usually wants to know if soil properties are changing from an identifiable condition or point of interest, such as an inherent baseline or an equilibrium condition established by business‐as‐usual soil and crop management practices. When soils are considered within social, political, economic, and environmental contexts, the type of benefits that can be documented expands (Heller and Keoleian, 2003; McBratney et al., 2014; Mena Mesa et al., 2014; Rasul and Thapa, 2004; Steffan et al., 2017; Wolde et al., 2016), but although those assessment scales are important to consider, they are outside the scope of this chapter because such changes, whether positive or negative, generally take several years (perhaps even decades) to be noticeable and/or measurable. This chapter focuses on agricultural research and discusses the general opportunities and limitations associated with soil health management approaches and strategies used to document potential soil physical, chemical, and biological property changes.
Introduction
There are several important questions associated with soil health research (Fig. 3.1). These include issues associated with more clearly defining the soil health concept, determining how to measure and quantify soil health at multiple scales, and using these principles to guide current and future soil and crop management decisions. As discussed in Chapter 2, questions regarding how to achieve effective soil management are not new (e.g., Bennett and Chapline, 1928; Hobbs, 2007; Janvier et al., 2007; Janzen, 2001; Karlen et al., 1997; Karlen et al., 2019; Magdoff and van Es, 2009; Stoll, 2003). Furthermore, several visual, in‐field, and laboratory methods for evaluating soil health have been developed over several decades. Answers to those questions are not simple because the living and dynamic nature of soils results in fiscal, human resource, intellectual, and other research constraints associated with sampling, analyzing, and interpreting how soil biological, chemical, and physical properties