Phosphorus Transfer in Surface Runoff from Intensive Pasture Systems at Various Scales
- Warwick J. Dougherty *a,
- Nigel K. Flemingb,
- Jim W. Coxc and
- David J. Chittleborougha
- a School of Earth and Environmental Sciences, University of Adelaide, PMB 1, Glen Osmond, South Australia, Australia 5064
b South Australian Research and Development Institute, PO Box 397, Adelaide, South Australia, Australia 5003
c CSIRO Land and Water, PMB 2, Glen Osmond, South Australia, Australia 5064
Phosphorus transfer in runoff from intensive pasture systems has been extensively researched at a range of scales. However, integration of data from the range of scales has been limited. This paper presents a conceptual model of P transfer that incorporates landscape effects and reviews the research relating to P transfer at a range of scales in light of this model. The contribution of inorganic P sources to P transfer is relatively well understood, but the contribution of organic P to P transfer is still relatively poorly defined. Phosphorus transfer has been studied at laboratory, profile, plot, field, and watershed scales. The majority of research investigating the processes of P transfer (as distinct from merely quantifying P transfer) has been undertaken at the plot scale. However, there is a growing need to integrate data gathered at a range of scales so that more effective strategies to reduce P transfer can be identified. This has been hindered by the lack of a clear conceptual framework to describe differences in the processes of P transfer at the various scales. The interaction of hydrological (transport) factors with P source factors, and their relationship to scale, require further examination. Runoff-generating areas are highly variable, both temporally and spatially. Improvement in the understanding and identification of these areas will contribute to increased effectiveness of strategies aimed at reducing P transfers in runoff. A thorough consideration of scale effects using the conceptual model of P transfer outlined in this paper will facilitate the development of improved strategies for reducing P losses in runoff.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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