HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Wagenet, R. J. Articles by Nielsen, D. R. Search for Related Content PubMed Articles by Wagenet, R. J. Articles by Nielsen, D. R. Agricola Articles by Wagenet, R. J. Articles by Nielsen, D. R.

Tracing the Transformations of Urea Fertilizer during Leaching¹

ABSTRACT

The transport and transformation of urea, NH₄⁺, and NO₃^- in soil were mathematically described as functions of depth and time, subject to either steady feed or pulse application of N, using relationships derived by assuming diffusion and mass transfer as transport processes and first-order kinetics as a transformational mechanism. The mathematical model was used to study the enzymatic hydrolysis of urea, nitrification, and denitrification in laboratory soil columns. Urea hydrolysis was found to be independent of initial urea concentration and the O₂ concentration of the soil atmosphere. The rate of nitrification under transient N conditions was found to be one order of magnitude greater than the rate of denitrification when there was 20% O₂ in the soil atmosphere. Populations of nitrifiers were found to increase in response to successive applications of N.

¹ Contribution from Dep. of Land, Air and Water Resour., Univ. of California, Davis, CA 95616. Research supported by Nat. Sci. Found.—RANN no. G134733X and the Kearney Found.

² Graduate Research Assistant and Professors of Water Sci., respectively. Senior author is presently Assistant Professor, Dep. of Soil Sci. and Biometeorology, Utah State Univ., Logan, UT 84322.

Received for publication November 1, 1976. Accepted for publication May 20, 1977.

This article has been cited by other articles:

				S. L. Zhao, S. C. Gupta, D. R. Huggins, and J. F. Moncrief Tillage and Nutrient Source Effects on Surface and Subsurface Water Quality at Corn Planting J. Environ. Qual., May 1, 2001; 30(3): 998 - 1008. [Abstract] [Full Text] [PDF]