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United States Department of Agriculture

Agricultural Research Service

Title: Phosphorus Concentrations in Runoff from Diverse Locations on a New York Dairy Farm

Authors
item Hively, W - CORNELL UNIVERSITY
item Bryant, Ray
item Fahey, T - CORNELL UNIVERSITY

Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 28, 2004
Publication Date: June 7, 2005
Citation: Hively, W.D., Bryant, R.B., Fahey, T.J. 2005. Phosphorus concentrations in runoff from diverse locations on a new york dairy farm. Journal of Environmental Quality. 34:1224-1233.

Interpretive Summary: Most water quality studies concerned with nutrient losses from agricultural non-point sources have focused on land use and management practices that are broadly representative of the farm landscape. In this study, simulated rainfall was used to quantify time to runoff, volume and phosphorus (P) concentrations from nine locations representing both spatially extensive field conditions and non-field conditions that are of limited spatial extent on a dairy farm in Delaware County, NY. Runoff from deciduous forest, extensively managed pasture, and two hillside seeps, exhibited low concentrations of total dissolved phosphorus (TDP). Runoff from intensively managed pastures, a hayfield, and a cow path yielded moderate TDP concentrations. A barnyard site with fresh manure deposits produced runoff with extremely high TDP concentrations. Concentrations of suspended solids were relatively low in runoff from vegetated sites, but were higher from sites with little groundcover (barnyard, cow path, plowed maize field). Under dry conditions, as simulated in mid-Summer on day one, time to runoff was shorter (< 23 minutes) for non-field areas (seep areas, barnyard, cow path) than for field areas (27 to 93 minutes). In contrast, under moist conditions, as simulated on day two, time to runoff was <23 minutes for all areas. These results suggest that during the dry summer months, which are characterized by brief, intense thunderstorms, non-field areas of minor spatial extent but with high P concentrations at the soil surface, such as cow paths and barnyards, appear to control TDP loading in streams during runoff events, and this explains the in-stream TDP concentrations that are typically higher by a factor of 3 or 4. Under wet winter and spring conditions, runoff from the extensive field areas dilutes runoff from these high P source non-field areas, resulting in relatively lower TDP concentrations in streams during runoff events. Comprehensive P loss management should address the minor landscape components, such as cow paths and barnyards, in addition to the crop lands and pastures.

Technical Abstract: The rainfall simulator developed for use in the National Phosphorus (P) Project was used to quantify time to runoff, volume and P concentrations from nine locations representing field and non-field conditions on a Delaware County, NY dairy farm. Runoff from deciduous forest, extensively managed pasture, and two hillside seeps, exhibited low (0.007 to 0.12 mg L-1) concentrations of total dissolved phosphorus (TDP). Runoff from intensively managed pastures, a hayfield, and a cow path yielded moderate TDP concentrations (0.18 to 0.64 mg L-1). A barnyard site with fresh manure deposits produced runoff with extremely high TDP concentration (11.6 mg L-1). Concentrations of TDP in runoff from sites without fresh manure could be predicted from Morgan's soil test phosphorus [TDP (mg L-1) = 0.0056 + 0.0180 * STP (mg kg-1); adjusted R2 = 84%], but the relationship did not hold for manured sites. Concentrations of suspended solids were relatively low in runoff from vegetated sites (16 to 137 mg L-1), but were higher (375 to 615 mg L-1) from sites with little groundcover (barnyard, cow path, plowed maize field). Under dry conditions, as simulated in mid-Summer on day one, time to runoff was shorter (< 23 minutes) for non-field areas (seep areas, barnyard, cow path) than for field areas (27 to 93 minutes), but under moist conditions, as simulated on day two, time to runoff was <23 minutes for all areas. During the dry summer months, which are characterized by brief, intense thunderstorms, non-field areas of minor spatial extent but with high P concentrations at the soil surface, such as cow paths and barnyards, appear to control TDP loading in streams during runoff events. Runoff from relatively large field areas under wet winter and spring conditions dilutes runoff from the non-field areas, resulting in overall lower TDP concentrations in streams during runoff events.

Last Modified: 11/22/2014
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