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This article in JEQ

  1. Vol. 41 No. 6, p. 1750-1757
    Received: Jan 3, 2012
    Published: October 16, 2012

    * Corresponding author(s): peter.vadas@ars.usda.gov
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Simulating Soil Phosphorus Dynamics for a Phosphorus Loss Quantification Tool

  1. Peter A. Vadas *a,
  2. Brad C. Joernb and
  3. Philip A. Moore Jrc
  1. a USDA–ARS, U.S. Dairy Forage Research Center, 1925 Linden Dr. W., Madison, WI 53706
    b Purdue Univ., West LaFayette, IN
    c USDA–ARS, Fayetteville, AR. Assigned to Associate Editor Andrew Sharpley


Pollution of fresh waters by agricultural phosphorus (P) is a water quality concern. Because soils can contribute significantly to P loss in runoff, it is important to assess how management affects soil P status over time, which is often done with models. Our objective was to describe and validate soil P dynamics in the Annual P Loss Estimator (APLE) model. APLE is a user-friendly spreadsheet model that simulates P loss in runoff and soil P dynamics over 10 yr for a given set of runoff, erosion, and management conditions. For soil P dynamics, APLE simulates two layers in the topsoil, each with three inorganic P pools and one organic P pool. It simulates P additions to soil from manure and fertilizer, distribution among pools, mixing between layers due to tillage and bioturbation, leaching between and out of layers, crop P removal, and loss by surface runoff and erosion. We used soil P data from 25 published studies to validate APLE’s soil P processes. Our results show that APLE reliably simulated soil P dynamics for a wide range of soil properties, soil depths, P application sources and rates, durations, soil P contents, and management practices. We validated APLE specifically for situations where soil P was increasing from excessive P inputs, where soil P was decreasing due to greater outputs than inputs, and where soil P stratification occurred in no-till and pasture soils. Successful simulations demonstrate APLE’s potential to be applied to major management scenarios related to soil P loss in runoff and erosion.

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Copyright © 2012. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.