|Wright-Morton, Lois -|
Submitted to: Advances in Soil Science
Publication Type: Book / Chapter
Publication Acceptance Date: August 1, 2012
Publication Date: June 25, 2013
Citation: Hatfield, J.L., Wright-Morton, L. 2013. Marginality principle. In: Lal, R., Stewart, B.A., editors. Principles of sustainable soil management in agroecosystems. Advances in Soil Science. Boca Raton, FL: CRC Press. p. 19-55. Technical Abstract: Soil is a fragile resource supplying many goods and services. Given the diversity of soil across the world and within a landscape, there are many different capacities among soils to provide the basic soil functions. Marginality of soils is a difficult process to define because the metrics to define a marginal soil depends upon the use, and if we utilize the framework of a soil capability classes then a marginal soil could be defined as one which moves from a higher to a lower soil class. The processes of soil degradation either from a biological, physical, or chemical viewpoint contributes to the marginality of soils and as a soil degrades, then it will become more marginal. However, a view of marginality of soil will depend upon the intended use of the soil. Water availability in the soil is a critical component for crop productivity and environmental quality, and a degraded soil with reduced capacity to either absorb, infiltrate, or retain water will provide marginal services for crop production and increased likelihood of increased environmental quality concerns. Soil degradation is a major threat to soils around the world and limits the capacity of a given soil to support the different functions of which providing food for humankind is foremost. Reversal of soil degradation by restoring organic matter and improving soil biological activity offsets the trend towards marginality in soils. Marginality in soils is not a new concept because we know that degraded soils have contributed to societal problems throughout history. However, the social view of soil and soil management provides a different dimension to our view of marginal soils. The perception is that soils are more degraded on other areas than what is being managed by an individual and their capability to manage and improve soil is better than others. The major problem is that the consequence of improper management and degradation is a gradual process rather than an immediate change and this leads to system in which we have grown tolerant of reductions in soil quality and trends toward marginality. Soil management practices need to renew their focus on eliminating soil erosion and enhancing soil biological function with the goal of ultimately increasing soil quality. Through this combination of focusing on soil enhancement we will be able to achieve the goal of being resilient to climate change and ensuring adequate food for an increasing population.