Skip to main content
ARS Home » Midwest Area » Madison, Wisconsin » U.S. Dairy Forage Research Center » Environmentally Integrated Dairy Management Research » Research » Publications at this Location » Publication #302344
Title: A new model for phosphorus loss in runoff from outdoor cattle lots

Author
item Vadas, Peter
item BUSCH, DENNIS - University Of Wisconsin
item GOOD, LAURA - University Of Wisconsin
item LARSON, REBECCA - University Of Wisconsin
item PANUSKA, JOHN - University Of Wisconsin

Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/26/2015
Publication Date: 8/3/2015
Citation: Vadas, P.A., Busch, D.L., Good, L.W., Larson, R.A., Panuska, J.C. 2015. A new model for phosphorus loss in runoff from outdoor cattle lots. Transactions of the ASABE. 58:1035-1045.

Interpretive Summary: Phosphorus loss from agriculture is a water quality issue. On cattle farms, barnyards and feedlots can be significant sources of phosphorus loss, and there is a need to estimate that loss. We developed a user-friendly model that predicts annual runoff, erosion, and phosphorus loss from barnyards and feedlots. The model requires input for only annual precipitation and lot characteristics, including surface type (paved or earthen), cattle number and type, and how often a lot is cleaned. The model estimates annual runoff using a dataset of precipitation events and a lot Curve Number, which is estimated from annual precipitation and lot surface type. The model estimates annual sediment loss based on annual runoff, and annual particulate phosphorus loss based on sediment loss and phosphorus content of manure in the lot, which is a function of animal type. The model estimates dissolved phosphorus loss for each runoff event in the precipitation dataset. Testing showed the model reliably predicts annual runoff, sediment loss, and phosphorus loss from barnyards and feedlots. The new model can be used to develop whole-farm estimates of phosphorus loss and effectively target phosphorus loss mitigation practices.

Technical Abstract: Phosphorus (P) loss from agriculture persists as a water quality issue. For cattle farms, nutrients can be lost from cropland, pastures, and barnyards and feedlots. Barnyards and feedlots can be significant sources of P loss, but there are few modeling tools to estimate that loss. We developed a user-friendly, spreadsheet model that predicts annual runoff, sediment loss, and total and dissolved P loss from barnyards and feedlots. The model requires input for only annual precipitation and lot characteristics, including surface type (paved or earthen), cattle number and type, and frequency of lot cleaning. The model estimates annual runoff using a dynamic dataset of precipitation events and a lot Curve Number, which is estimated empirically based on annual precipitation and lot surface type. The model estimates annual sediment loss based on annual runoff, and annual particulate P loss based on sediment loss and P content of manure in the lot, which is a function of animal type. The model estimates dissolved P loss for each runoff event in the precipitation dataset. Testing with data from 12 studies showed the model was able to reliably estimate annual runoff, sediment loss, and P loss from barnyards and feedlots representing a variety of climates and managements. The new model also gave more reliable predictions than the MinnFarm and BARNY models, which are currently used barnyard and feedlot models. The new P runoff model provides a valuable tool to develop whole-farm estimates of P loss and more effectively target P loss mitigation practices.