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United States Department of Agriculture

Agricultural Research Service

Title: Managing phosphorus for water quality protection - 10 principles)

item Kleinman, Peter
item Tao, Liang
item Sharpley, Andrew
item Flaten, Don
item Mcdowell, Richard
item Bergstrom, Lars
item Buda, Anthony

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 8/1/2010
Publication Date: 10/1/2010
Citation: Kleinman, P.J., Tao, L., Sharpley, A.N., Flaten, D., Mcdowell, R., Bergstrom, L., Buda, A.R. 2010. Managing phosphorus for water quality protection - 10 principles [abstract]. 4th International Symposium on Phosphorus Dynamics in Soil-Plant Continuum, September 19-23, 2010. Beijing China. p. 1.

Interpretive Summary: An interpretive summary is not required.

Technical Abstract: The accelerated eutrophication of aquatic systems has primarily been the concern of developed nations where it represents the most pervasive impairment of surface water bodies. Managing phosphorus for water quality protection requires prudent tempering of agronomic emphases to build soil phosphorus, recognizing that environmental buffers can and do reverse, and that principals of soil conservation must be balanced with the control of dissolved phosphorus in runoff. Nowhere are the lessons of environmental phosphorus management more apparent than in modern, intensive livestock farming systems where manure phosphorus can be transformed from resource to liability. However, these systems, which often involve vertically integrated production chains, are also the best equipped to address strategic problems. Furthermore, diffuse losses of phosphorus are far from restricted to intensive livestock production systems; even low-intensity farming systems can yield significant loads of phosphorus to local surface waters. We explore case studies from across the developed world to divine 10 principals about the management of diffuse phosphorus pollution in agricultural systems. Strategies to mitigate diffuse losses of phosphorus from agriculture must consider chronic (edaphic) and acute (fertilizer, manure) sources (Principles 1 and 2). Even then, hydrology can readily overwhelm these controls, converting even modest sources into significant environmental loads (Principle 3). Moreover, different hydrologic processes can undermine or reverse the benefits of management practices aimed at controlling diffuse phosphorus losses (Principle 4). As our understanding of phosphorus transfer processes improves, so too does our awareness of the importance of different transport pathways, with subsurface pathways increasingly viewed as a major concern (Principle 5), albeit manageable with well placed field practices (Principle 6). Systemic drivers, particularly phosphorus imbalances that result in long-term over-application of phosphorus to soils, are the most recalcitrant causes of diffuse phosphorus losses, requiring many decades to reverse (Principle 7). Even in systems where phosphorus imbalances are not as severe, diffuse pollution can be exacerbated by management systems that promote concentrations of phosphorus within the effective depth of interaction between soils and runoff water (Principle 8). Indeed, low-intensity grazing systems with extensive land resources must be conscientiously managed to prevent transfers of phosphorus to surface waters (Principle 9). Understanding the limits of phosphorus management strategies is essential to ensure that water quality expectations are realistic (Principle 10).

Last Modified: 04/25/2017
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