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 Google Scholar Google Scholar Articles by McIntosh, T. H. Articles by Frederick, L. R. Search for Related Content PubMed Articles by McIntosh, T. H. Articles by Frederick, L. R. Agricola Articles by McIntosh, T. H. Articles by Frederick, L. R.

Distribution and Nitrification of Anhydrous Ammonia in a Nicollet Sandy Clay Loam¹

ABSTRACT

A roughly cylindrical distribution of NH₃ centered at the knife openings was found when anhydrous ammonia was applied with a field applicator at a depth of 4 inches, by sampling an 8- by 8- by 2-inch cross section perpendicular to the applicator row. NH₄-N, NO₃-N and pH were determined on each 1-inch square subsample. NH₄-N decreased from a maximum concentration of 1,300 to 2,000 ppm. (pH 9.5) at the center to less than 200 ppm. (pH 8) in the area about 1 inches away from the center of the retention zone. After 2 weeks, the maximum concentration of NH₄-N was about 800 ppm. (pH 8.8) in the center decreasing to less than 100 ppm. (pH 7.0) in the area about 2 inches away from the center of the retention zone.

Nitrification initially proceeded more rapidly in the outside 2 inches of the retention zone where the concentration of NH₄-N was less than 400 ppm. Later in the original ammonia retention zone, nitrification appeared to be limited by low pH and nitrate concentration; at the end of 4 weeks the pH had decreased to a value of 5.0 to 5.5 and NO₃-N had increased until 200 to 300 ppm. were present. Ammonia applied in November just prior to freezing showed little nitrification by March. Rapid nitrification began in mid-April when soil temperatures rose above 40° F. Approximately 8 weeks were required to completely nitrify the ammonia.

¹ Journal Paper No. J-3339 of the Iowa Agri. and Home Econ. Exp. Sta., Ames, Iowa. Project No. 1070. This work was supported in part by a grant from Phillips Petroleum Co. Presented before Div. III, Soil Science Society of America, Nov. 20, 1957, at Atlanta, Ga.

² Graduate Assistant and Associate Professor of Soils, respectively, Agronomy Department, Iowa State College.

Received for publication February 14, 1958. Accepted for publication April 16, 1958.