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Soil Science Society of America Journal Abstract - DIVISION S-7—FOREST & RANGE SOILS

Soil Analyses as Indicators of Phosphorus Response in Young Eucalypt Plantations


This article in SSSAJ

  1. Vol. 66 No. 3, p. 959-968
    Received: Sept 20, 2000

    * Corresponding author(s): Daniel.Mendham@csiro.au
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  1. Daniel S. Mendham *a,
  2. Philip J. Smethurstb,
  3. Greg K. Holzc,
  4. Robert C. Menaryd,
  5. Tim S. Grovee,
  6. Chris Westonf and
  7. Tom Bakerg
  1. a Cooperative Research Centre for Sustainable Production Forestry and CSIRO Forestry and Forest Products, Private bag No. 5, Wembley, WA, Australia 6913
    b Cooperative Research Centre for Sustainable Production Forestry and CSIRO Forestry and Forest Products, GPO Box 252-12, Hobart, Tasmania, Australia 7001
    c Gunns Ltd., P.O. Box 63 Ridgley, Tasmania, Australia 7321
    d Dep. of Agricultural Science, University of Tasmania, GPO Box 252-54, Hobart, Tasmania, Australia 7001
    e CSIRO Forestry and Forest Products, Private Bag No. 5, Wembley, WA, Australia 6913
    f Institute of Land and Food Resources, The University of Melbourne, Royal Parade, Parkville Victoria, Australia 3052
    g Centre for Forest Tree Technology, P.O. Box 137, Heidelberg, Victoria, Australia 3084


The use of P fertilizer in Eucalyptus plantations can result in significant and economically viable increases in timber production. Soil analyses could potentially indicate sites requiring more P fertilizer than is currently applied and prevent excess P fertilizer application on sites where little or no response would be obtained. The ability of several soil P analyses to predict first year growth responses of E. nitens and E. globulus to P fertilizer was assessed in 24 previously established field experiments situated in southeast and southwest Australia on a range of soil types. Soil P analyses that were assessed included an intensity-based analysis (CaCl2 extracted P), quantity-based analyses (total P, bicarbonate extracted P, and Bray No. 2 P), and quantity–intensity relationships (P adsorption curves). An excellent relationship was found between CaCl2-extractable P (range: 26–162 μg kg−1, R 2 = 0.83) and first year growth response to P applied at planting for 21 of the 24 field experiments. Quantity-based P analyses, such as bicarbonate P (range: 2–63 μg g−1, R 2 = 0.43), Bray No. 2 P (range: 0.1–15 μg g−1, R 2 = 0.30), acid-extractable P (range: 0.6–11 μg g−1, R 2 = 0.37), and total P (range: 0.038–3.5 mg g−1, R 2 = 0.39) did not correlate as well with plant growth response to P application. However, quantity-based P analyses may be useful if specific calibrations were developed for a limited range of soils. Inclusion of P adsorption data in multiple regressions of soil P concentration against relative yield generally did not improve the relationships. The excellent relationship between plantation response to P fertilizer and soil P intensity suggested that such analyses may be useful for managing P fertilizer in eucalypt plantations across the wide range of sites where eucalypts are currently being planted.

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Copyright © 2002. Soil Science SocietyPublished in Soil Sci. Soc. Am. J.66:959–968.