Rates of nitrification of 3 urea-based fertilizers in 4 Iowa soils. (4740)
Authors:
M. Gonzalez* - Iowa State University R.J. Killorn - Iowa State University E. Rovita - Iowa State University
Abstract:
After urea is hydrolyzed, biological oxidation of NH4+ takes place increasing the chance of denitrification and leaching of NO3-. A slow-release N fertilizer has been developed by Georgia Pacific Inc. to improve the effectiveness of urea based
fertilizers. An incubation study was performed to evaluate the nitrogen release rates of this product to compare it with regular urea in four Iowa soils. 10g samples of the soils were treated with 1 ml of solution containing rates of N equivalent to 0, 50, 100, 150 and 200 kg ha-1 and incubated at 20 C and 0.03 MPa of soil moisture for 0, 7, 15, 30, 45 and 60 d. Verhulst's equation was used to express the
accumulation of NO3- with time; the maximum nitrification rate (Kmax), duration of the lag period (t') and period of maximum nitrification were also calculated.
Kmax values were markedly different among rates and soils but were similar
among N sources. A significant interaction between N source and rate was found in three of the soils.
Speaker Information: Marianela Gonzalez, Iowa State University, 3210 Agronomy Hall Iowa State University, Ames, IA 50011-1010; Phone: 515 294-4264; E-mail:
Session Information: Tuesday, November 2, 2004, 1:00 PM-5:00 PM Presentation Start: 1:00 PM (Poster Board Number: 2653)
