Exchangeable ammonium and nitrate from different nitrogen fertilizer preparations in polyacrylamide-treated and untreated agricultural soils

Jeanine L. Kay-Shoemake, Maribeth E Watwood, Lisa Kilpatrick, Krista Harris

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High molecular weight, anionic polyacrylamide (PAM) is currently being used as an irrigation water additive to significantly reduce soil erosion associated with furrow irrigation. PAM contains amide-N, and PAM application to soils has been correlated with increased activity of soil enzymes, such as urease and amidase, involved in N cycling. Therefore we investigated potential impacts of PAM treatment on the rate at which fertilizer N is transformed into NH4/+ and NO3/- in soil. PAM-treated and untreated soil microcosms were amended with a variety of fertilizers, ranging from common rapid-release forms, such as ammonium sulfate [(NH4)2SO4] and urea, to a variety of slow-release formulations, including polymerized urea and polymer-encapsulated urea. Ammonium sulfate was also tested together with the nitrification inhibitor dicyandiamide (DCD). The fertilizers were applied at a concentration of 1.0 mg g-1, which is comparable to 100 lb acre-1, or 112 kg ha-1. Potassium chloride-extractable NH4/+-N and NO3/--N were quantified periodically during 2-4 week incubations. PAM treatment had no significant effect on NH4/+ release rates for any of the fertilizers tested and did not alter the efficacy of DCD as a nitrification inhibitor. However, the nitrification rate of urea and encapsulated urea-derived NH4/+ -N was slightly accelerated in the PAM-treated soil.

Original languageEnglish (US)
Pages (from-to)245-248
Number of pages4
JournalBiology and Fertility of Soils
Issue number3-4
StatePublished - Jun 2000
Externally publishedYes



  • Dicyandiamide
  • Nitrogen fertilizer
  • Polyacrylamide
  • Polymer-encased urea
  • Polymerized urea

ASJC Scopus subject areas

  • Soil Science

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