Submitted to: Journal of ASTM International
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/20/2008
Publication Date: 1/1/2009
Citation: Sojka, R.E., Lehrsch, G.A., Kostka, S.J., Reed, J.L., Koehn, A.C., Foerster, J.A. 2009. Soil Water Measurements Relevant to Agronomic and Environmental Functions of Chemically Treated Soil. Journal of ASTM International. 6(1):1-20. Interpretive Summary: Many in the chemical industry and in various facets of turf and landscape management, who employ herbicides, pesticides, fungicides, and various soil and nutrient amendments, are highly trained in chemistry and related specialties, but have little or no expertise in soil physics. Soil physics provides the principles and measurement expertise to properly assess the status of water in soil, and concomitantly, the transport of applied chemicals that move with, or under the influence of soil water. While it is not possible to provide a thorough understanding of this enormous field of environmental science in a single paper, it is useful to have a concise guide to key concepts. The authors were invited to provide a summary of key principles of soil physics and soil water monitoring technologies to guide turf and landscape specialists interested in better assessing water status and its influence on applied chemicals. This paper describes the soil three phase system, the major categories of water status (quantity, energy status, and internal flow), the dominant measurement techniques, and give a brief description of how these principles and measurements relate to the movement of chemicals in soil.
Technical Abstract: Modern agricultural, turf and landscape management routinely apply and depend upon chemical applications to optimize system function for specific outcomes. The effectiveness of these applied chemicals to achieve desired outcomes usually depends upon their interaction with and transport by water. To fully and accurately assess the role of water as a chemical delivery and activation system requires a good understanding of how the applied chemicals, soil, and water interact, the scale at which a phenomenon is important, the nature of soil variability, and which of the three dominant soil water properties (content, movement, or potential energy) is most important in assessing water’s role. The science of this assessment process is extensive and its literature is voluminous. For the uninitiated, however, it is worth being aware at least of the basics of soil water assessment and where some of the pitfalls lie. This presentation describes soil as a three phase system (solids, liquid and gases) and highlights some of the key measurements and measurement considerations necessary to appropriately characterize treatment efficacy for specific, and especially, non-intuitive effects. The presentation cannot be comprehensive or substitute for requisite university-level courses in soil physics and soil chemistry, but can, perhaps, alert applicators to situations and considerations that demand more than mere cursory assessment for proper evaluation and interpretation.