Author
|
Submitted to: Soil and Water Conservation Society Proceedings
Publication Type: Abstract Only Publication Acceptance Date: 2/9/2016 Publication Date: 8/17/2016 Citation: Bolster, C.H. 2016. Estimating the magnitude of prediction uncertainties for field-scale P loss models. Soil and Water Conservation Society Proceedings. 45. Interpretive Summary: Technical Abstract: Models are often used to predict phosphorus (P) loss from agricultural fields. While it is commonly recognized that model predictions are inherently uncertain, few studies have addressed prediction uncertainties using P loss models. In this study, an uncertainty analysis for the Annual P Loss Estimator (APLE) model was performed by estimating the uncertainty associated with model input variables and model parameters. Specifically, a method is presented for estimating model parameter uncertainties associated with the regression equations used to estimate total soil P from measurements of soil clay content, organic matter, and labile P; the P enrichment ratio from erosion rates; concentration of P in runoff due to labile soil P; and partitioning of P between runoff and infiltration from applied manures and fertilizers. Uncertainty associated with model input variables was based on error estimates published in the literature. This analysis included calculating both confidence and prediction intervals. The relative magnitudes of the two sources of uncertainty to the overall uncertainty associated with APLE predictions of P loss are compared. How estimation of model parameter uncertainty can identify model limitations is also discussed. |
