Abstract
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 language | English (US) |
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Pages (from-to) | 245-248 |
Number of pages | 4 |
Journal | Biology and Fertility of Soils |
Volume | 31 |
Issue number | 3-4 |
DOIs | |
State | Published - Jun 2000 |
Externally published | Yes |
Keywords
- Dicyandiamide
- Nitrogen fertilizer
- Polyacrylamide
- Polymer-encased urea
- Polymerized urea
ASJC Scopus subject areas
- Microbiology
- Agronomy and Crop Science
- Soil Science