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Phosphorus Fertilization Responses on Bahiagrass Pastures: Forage Production and Water Quality


This article in AJ

  1. Vol. 103 No. 2, p. 324-330
    Received: July 27, 2010

    * Corresponding author(s): jv@ufl.edu
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  1. A. K. Oboura,
  2. J. M. B. Vendramini *a,
  3. M. L. Silveiraa,
  4. L. E. Sollenbergerb,
  5. G. A. O'Connorc and
  6. J. W. Jawitzc
  1. a Range Cattle Research and Education Center, University of Florida, Ona 33865
    b Agronomy Dep., University of Florida, Gainesville 32611
    c Soil and Water Sci. Dep., University of Florida, Gainesville 32611


The increased cost of fertilizer and concerns about environmental impacts have led to a reduction in P use in grazed pastures in Florida; however, P fertilization may be necessary to sustain bahiagrass (Paspalum notatum Flügge) pastures. This study evaluated the impacts of reduced P fertilization on forage characteristics, soil and leachate P concentrations on bahiagrass pastures during 2007 and 2008. Treatments consisted of three P fertilization levels (0, 5, and 10 kg P ha−1, applied as KH2PO4) arranged in a randomized complete block design with four replicates. Twelve 1.2-ha bahiagrass pastures were stocked continuously with a fixed stocking rate of two beef heifers [Bos sp; 380 ± 30 kg live weight (LW)] per experimental unit. Forage was sampled at 14-d intervals for herbage mass (HM), crude protein (CP), and in vitro digestible organic matter (IVDOM) concentrations. Two suction lysimeters were installed at 60- and 90-cm depth to monitor leachate P. Phosphorus fertilization did not affect HM (4.4 Mg ha−1), herbage accumulation rate (HAR, 43 kg ha−1 d−1), CP (94 g kg−1), or IVDOM (500 g kg−1). Tissue P concentrations increased from 1.9 to 2.2 g kg−1 as P fertilization increased from 0 to 10 kg P ha−1 Soil P concentration in the Ap (7 mg kg−1) and Bh horizons (23 mg kg−1) and leachate P concentration (0.06 mg L−1) were not affected by P application. Despite the lack of yield response to P fertilization, P application at levels of 5 and 10 kg P ha−1 showed no impacts on water quality.

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Copyright © 2011. American Society of AgronomyCopyright © 2011 by the American Society of Agronomy