|Blombach, Karin - Swedish University Of Agricultural Sciences|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/15/2017
Publication Date: 6/2/2017
Citation: Bolster, C.H., Blombach, K. 2017. Improving models for describing phosphorus cycling in agricultural soils. Meeting Abstract. Paper No. 34.
Technical Abstract: The mobility of phosphorus in the environment is controlled to a large extent by its sorption to soil. Therefore, an important component of all P loss models is how the model describes the biogeochemical processes governing P sorption and desorption to soils. The most common approach to modeling P cycling in soils is based on the equations developed for the Erosion-Productivity Impact Calculator (EPIC) model. An important parameter needed for this model is the P sorption capacity parameter (PSP) which is used to distribute added P to different soil P pools. In most cases this parameter is not directly measured but rather estimated from soil properties. As a result, a significant amount of uncertainty is associated with this parameter. In this study we investigate the magnitude of this uncertainty and how it influences predictions of P loss from soil. Specifically, we re-evaluate existing regression equations relating PSP to soil texture properties and estimate the uncertainties associated with the regression equation. We then apply these uncertainties to predictions of PSP values and compare these with measured PSP values. Finally, we evaluate the impact these uncertainties have on predictions of P loss from soil and discuss ways to reduce these uncertainties.