Skip to main content
ARS Home » Northeast Area » University Park, Pennsylvania » Pasture Systems & Watershed Management Research » Research » Publications at this Location » Publication #124137
Title: PHOSPHORUS TRANSPORT IN OVERLAND FLOW IN RESPONSE TO POSITION OF MANURE

Author
item MCDOWELL, RICHARD - PENN STATE UNIVERSITY
item Sharpley, Andrew

Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/12/2002
Publication Date: 1/20/2002
Citation: MCDOWELL, R., SHARPLEY, A.N. PHOSPHORUS TRANSPORT IN OVERLAND FLOW IN RESPONSE TO POSITION OF MANURE APPLICATION. JOURNAL OF ENVIRONMENTAL QUALITY. 2002. V. 31(1). P. 217-227.

Interpretive Summary: Phosphorus (P) is a key element in the nutrition of plants and the eutrophication of surface waters. The loss of P from soil to surface waters is mediated by the hydrological conditions controlling water flow (e.g., overland and subsurface flow) and can occur in both dissolved and particulate forms. In the continental climate of the northeast U.S., most P is lost via overland pathways. In this study, we hypothesized that if a recently manured soil is far enough upslope, the concentration of P in overland flow may decrease to less than that required to cause eutrophication by the time flow reaches surface water. The purpose of this study was to examine processes and fractions of P within overland flow, with and without a localized manure application at various distances upslope for two soils that dominate a watershed in central Pennsylvania. Previous work has shown that physical transport mechanisms and sources of P Pwithin this watershed are controlled largely by landscape position. Thus, a secondary objective was to estimate where from within our watershed manured soils would affect P export. We found that while P loss in overland flow is affected by where manure is applied on a hill slope, the amount of P initially in the soil also influences how much P is lost. Thus, both how much and where manure is applied, as well as soil P level, should be considered when looking for areas of potential P loss within a watershed.

Technical Abstract: Phosphorus (P) loss in overland flow varies with spatial distribution of soil P, management, and hydrological pathways. The effect of flow-time, flowpath length, and manure position on P loss in overland flow from two soils (from central Pennsylvania - Watson and Berks), packed in boxes of varying length (0.5, 1.0, 1.5, 2.75, and 4.0 m long by 15-cm wide and 5-cm deep), were examined by collecting flow samples at 5 min intervals for 30 min (5 cm/hr rainfall) without and with 75 kg P/ha applied as swine manure over 0.5 m of the box slope length at distances of 0 to 3.5 m from the downslope collection point. Dissolved reactive P concentration was more closely related to the proportion of clay in sediment of overland flow before (r = 0.98) than after (r = 0.56) manure application. This was attributed to the transport of larger, low-density particles after applying manure. The concentration of dissolved and particulate P fractions decreased with increasing flowpath length, due to dilution rather than sorption of P by surface soil during overland flow. Total P loss (mainly as particulate P) from the Watson soil was more than from Berks, even with manure applied. Thus, while P loss in overland flow is affected by where manure is applied relative to flowpath length, initial soil P concentration should not be discounted when looking at areas of potential P loss within a watershed.