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This article in JEQ

  1. Vol. 33 No. 3, p. 965-975
     
    Received: June 25, 2003


    * Corresponding author(s): gerwin.koopmans@wur.nl
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doi:10.2134/jeq2004.0965

Phosphorus Availability for Plant Uptake in a Phosphorus-Enriched Noncalcareous Sandy Soil

  1. G. F. Koopmans *a,
  2. W. J. Chardona,
  3. P. A. I. Ehlerta,
  4. J. Dolfinga,
  5. R. A. A. Suursa,
  6. O. Oenemaa and
  7. W. H. van Riemsdijkb
  1. a Alterra, Wageningen University and Research Centre (WUR), P.O. Box 47, 6700 AA, Wageningen, the Netherlands
    b Department of Soil Quality, Wageningen University, WUR, P.O. Box 8005, 6700 EC, Wageningen, the Netherlands

Abstract

Mining soil phosphorus (i.e., harvesting P taken up from the soil by a crop grown without external P addition) has been proposed as a possible management strategy for P-enriched soils to decrease the risk of P leaching. We performed a pot experiment in a greenhouse where grass was cropped on a P-enriched noncalcareous sandy soil at zero P application over a period of 978 d. We determined the long-term availability of soil P and evaluated the effectiveness of mining soil P to decrease P in different pools. There were two treatments: soil layers in the pots of either 5 or 10 cm thickness. Soils were analyzed at various stages of the experiment. Phosphorus in soil solution and the total pool of sorbed P were estimated using 1:10 (w/v) 0.01 M CaCl2 extracts and acid ammonium oxalate (Pox), respectively. A desorption isotherm was constructed, which described the relationship between P in soil solution and the total pool of sorbed P for the soils of the 5- and 10-cm treatments. The Langmuir equation gave a very good description of the isotherm. In the long-term, 65% of Pox in the initial soil can be removed by plant uptake, as was calculated from the Langmuir equation and a critical P concentration in soil solution at which P uptake can just be maintained. Thus, Pox may be largely plant available. From the strong nonlinearity of the desorption isotherm, it can be understood why the relative decrease of the P concentration in the CaCl2 extracts was much larger than the relative decrease of Pox Mining soil P decreased the P concentration in soil solution effectively and, therefore, risk of P leaching from our P-enriched soil.

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Copyright © 2004. American Society of Agronomy, Crop Science Society of America, Soil Science SocietyASA, CSSA, SSSA