Phosphorus Transfer in Surface Runoff from Intensive Pasture Systems at Various Scales

Abstract

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.

Assessment the Physico-Chemical Characteristics of Water and Sediment in Rosetta Branch, Egypt

“…The lowest mean values of TP and TN were recorded in site 3, while the highest mean value of both were recorded in site 2 opposite to different drains that discharging huge amounts of sewage, domestic and agricultural wastes into the Rosetta Branch without any treatment, this leading to the increase in the concentration levels of nutrients. High values of TP and TN are related to agricultural wastes this agrees with the findings of Dougherty et al [35] and Abdo [33].…”

Phosphorus Distribution in Soils from Australian Dairy and Beef Rearing Pastoral Systems

“…In particular, it is known that the slope of a sampling site may impact on excess overland flow (surface water runoff) [59] and can, in turn, influence P retention and/or transport. In south-eastern Australia and other temperate regions, surface runoff is considered the predominant pathway for P transport [60][61][62].…”

Runoff Losses of Dissolved Reactive Phosphorus from Organic Fertilizer Applied to Sod

“…Phosphorus lost in runoff often makes its way to surface water bodies, where it can cause eutrophication in freshwater systems that are generally P limited (Correl, 1998). Eutrophication can impair water use for drinking, recreation, habitat, and industrial use by producing algal blooms and reducing the dissolved oxygen content of the water (Dougherty et al, 2004). The authors are Barbara J. Baker, ASABE Member, Soil Scientist, and Kevin W. King, ASABE Member Engineer, Agricultural Engineer, USDA-ARS Soil Drainage Research Unit, Columbus, Ohio; H. Allen Torbert, USDA-ARS National Soil Dynamics Laboratory, Auburn, Alabama.…”

“…The authors are Barbara J. Baker, ASABE Member, Soil Scientist, and Kevin W. King, ASABE Member Engineer, Agricultural Engineer, USDA-ARS Soil Drainage Research Unit, Columbus, Ohio; H. Allen Torbert, USDA-ARS National Soil Dynamics Laboratory, Auburn, Alabama. Corresponding author: Barbara J. Baker, USDA-ARS Soil Drainage Research Unit, 590 Woody Hayes Dr., Columbus,OH 43210; Mobilization of phosphorus can be broadly broken down into two categories: physical detachment and subsequent entrainment of particles on which P is bound, and chemical processes in which phosphate ions are released into solution (Dougherty et al, 2004). In grassland systems, physical detachment is limited due to dissipation of raindrop impact by the canopy (Easton and Petrovic, 2004).…”

“…Runoff concentration of P is controlled by chemical, biological, physical, and hydrological factors (Dougherty et al, 2004). The elapsed time between application of organic fertilizers and runoff has been shown to have little effect on the concentration of dissolved P in runoff from grassland systems (Schroeder et al, 2004).…”