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This article in SSSAJ

  1. Vol. 70 No. 1, p. 163-171
     
    Received: Mar 31, 2005
    Published: Jan, 2006


    * Corresponding author(s): jschrod@okstate.edu
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doi:10.2136/sssaj2005.0102

Phosphorus Loss in Runoff from Long-term Continuous Wheat Fertility Trials

  1. H. Zhanga,
  2. J. L. Schroder *a,
  3. R. L. Davisc,
  4. J. J. Wangd,
  5. M. E. Paytonb,
  6. W. E. Thomasone,
  7. Y. Tangf and
  8. W. R. Rauna
  1. a Dep. of Plant and Soil Sciences
    c Apex Environmental Inc., Lenexa, KS 66215
    d Dep. of Agronomy and Environmental Management, Louisiana State Univ., Baton Rouge, LA 70803
    b Dep. of Statistics, Oklahoma State Univ., Stillwater, OK 74078
    e Dep. of Crop and Soil Environmental Sciences, Virginia Polytechnic Institute and State Univ., Blacksburg, VA 24061
    f Yangzhou Univ., Jiangsu, China

Abstract

Some wheat (Triticum aestivum L.) farmers in the southern Great Plains routinely apply P fertilizer without soil testing. This practice may lead to P buildup in soils, hence, increased P runoff potential, making soil P management of concern in continuous wheat production. At present, there is also debate over the nature of P loss trends, particularly whether soil P release to runoff can be described generally, across a broad range of soils, or is soil-specific. Paired 1 m by 2 m runoff plots were established on three existing long-term continuous winter wheat fertility experiments. Two experiments have received annual fertilizer P application at different rates since 1970 (0–44 kg P ha−1), and the third received a one-time P application at much higher rates in 1977 (0–587 kg P ha−1). Rainfall-runoff experiments were conducted following the National P Research Project protocol. Simulated rain (75 mm h−1) produced 30 min of runoff from plots with different soil test P levels. Soil Mehlich-3 P (M3P) ranged from 11.5 to 130 mg kg−1 and water-soluble P (WSP) ranged from 0.70 to 15.7 mg kg−1 Runoff total P and dissolved reactive P (DRP) concentrations ranged from 0.47 to 1.5 and 0.03 to 0.70 mg L−1, respectively. Dissolved reactive P in runoff was significantly related to M3P, WSP, and ammonium oxalate P saturation index (PSIox) for combined soils as well as for individual soil series. Significant differences (p < 0.05) among the slopes of the regressions for the DRP-M3P, DRP-WSP, and DRP-PSIox relationships indicate that the relationships are soil specific. This study highlights the need for soil specific management to protect water quality.

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Copyright © 2006. Soil Science SocietySoil Science Society of America