Relationships between soil organic carbon and soil quality in cropped and rangeland soils: the importance of distribution, composition, and soil biological activity

TitleRelationships between soil organic carbon and soil quality in cropped and rangeland soils: the importance of distribution, composition, and soil biological activity
Publication TypeBook Chapter
Year of Publication1997
AuthorsHerrick JE, Wander M.M.
EditorLal R., Kimble J.M., Follett R.F., Stewart B.A.
Book TitleSoil Processes and the Carbon Cycle
Chapter28
Pagination405-425
PublisherCRC Press LLC
CityNew York, NY
AbstractThe often-cited positive relationship between soil organic carbon (SOC) content and soil quality (Arshad and Coen, 1992; National Research Council, 1993; Doran and Parkin, 1994; Manley et al., 1995; Pikul and Aase, 1995; Karlen and Cambardella, 1996) is consistent with the results of over one hundred years of modern agricultural research (Bauer and Black, 1994) and with thousands of years of on-farm observation and experimentation (Magdoff, 1992). This relationship is based on contributions which SOC makes as a constituent of soil organic matter (SOM) to critical soil properties, processes and functions. The term "SOM" will be used in the remainder of this chapter except where carbon per se is of interest. SOM is preferred here because it reflects the reality that impacts of SOC on soil quality are determined by its chemical, physical, and biological configuration within SOM. The positive correlation between SOM and soil quality holds, in general, for all of the definitions of soil quality listed by Doran and Parkin (1994), as well as for the concepts of soil quality discussed by Warkentin (1995). Soil organic matter content was listed by a group of 28 Wisconsin farmers as the single most important property for characterizing soil health or soil quality based on their personal definitions (Romig et al., 1995). SOM was also cited as "perhaps the single most important indicator of soil quality" in a National Research Council report on soil and water quality. The report defined soil quality as "the capacity of the soil to promote the growth of plants; protect watersheds by regulating the infiltration and partitioning of precipitation; and prevent water and air pollution by buffering potential pollutants such as agricultural chemicals, organic wastes, and industrial chemicals" (National Research Council, 1993). For the purposes of this chapter, soil quality is defined as the capacity of a soil to perform functions which sustain biological productivity and maintain environmental quality. Soil quality depends on current soil functional integrity and on soil's resistance to, and resilience following, perturbation. Resistance is inversely proportional to loss of soil functional integrity following perturbation, while resilience is proportional to the recovery of functional integrity (Figure 1; Pimm, 1984). It is clear that a general relationship exists between SOM content, soil functions, and the capacity of the soil to maintain and/or recover those functions over time.
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