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This article in SSSAJ

  1. Vol. 66 No. 5, p. 1696-1705
    Received: Aug 13, 2001

    * Corresponding author(s): apmallar@iastate.edu
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Agronomic and Environmental Soil Phosphorus Testing in Soils Receiving Liquid Swine Manure

  1. A. M. Atiab and
  2. A. P. Mallarino *a
  1. b Alberta Agriculture Food and Rural Development, 6903 116 Street, Edmonton, AB, Canada T6H 4P2 (formerly Graduate Research Assistant, Dep. of Agronomy, Iowa State Univ.)
    a Dep. of Agronomy, Iowa State Univ., Ames, IA 50011


There is uncertainty concerning evaluation of bioavailable P in manured soils. This study assessed P availability in manured Iowa soils by measuring soil P with agronomic and environmental P tests and P uptake by corn (Zea mays L.) and soybean [Glycine max (L.) Merr.]. Soil and plant samples were collected at the V5-V6 growth stage from trials established at nine locations that received various rates of liquid swine (Sus scrofa) manure, and from farmers' fields that received other animal manures. Soil P was analyzed by the Bray-P1 (BP), Olsen (OP), and Mehlich-3 (M3P) agronomic tests, and by the Fe-oxide impregnated filter paper (FeP), anion-exchange resin membrane (RP), and water (WP) environmental tests. Soil P at a 15-cm depth ranged from deficient to 15 times optimum levels for crops. Extracted P was highest for BP, M3P, and RP, intermediate for OP and FeP, and lowest for WP. Relationships between soil P extracted by the tests were linear, trends were similar for manured and unmanured plots, and correlation coefficients were ≥0.70 (correlations were poorest for WP). There was no conclusive evidence for differences between tests in detecting manure-derived soil P at most sites. However, in some conditions BP, M3P, OP, and RP may extract proportionally more manured-derived P than FeP and WP. Only the agronomic tests were significantly correlated (0.42 for M3P, 0.44 for BP, and 0.47 for OP) with plant P uptake across sites. Agronomic soil tests would predict plant P availability for crops better than environmental P tests in soils receiving liquid swine manure.

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Copyright © 2002. Soil Science SocietyPublished in Soil Sci. Soc. Am. J.66:1696–1705.