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 Keeney, D. R. Articles by Bremner, J. M. Search for Related Content PubMed Articles by Keeney, D. R. Articles by Bremner, J. M. Agricola Articles by Keeney, D. R. Articles by Bremner, J. M.

Effect of Cultivation on the Nitrogen Distribution in Soils¹

ABSTRACT

The effect of cultivation on the nitrogen distribution in soils was studied by determining total N, nonexchangeable ammonium N, nonhydrolyzable N, and hydrolyzable (total, ammonium, hexosamine, amino acid, unidentified) N in 10 virgin soils and their cultivated analogues.

Cultivation led to a marked decrease in all forms of N, excepting nonexchangeable ammonium N, but, on the average, had little effect on the percentage distribution of N. The average percent loss of total N on cultivation was 36.2%, and the average losses of different forms of N, calculated as percentages of the loss in total N, decreased in the order: hydrolyzable N (70.5%) > amino acid N (29.8%) > nonhdrolyzable N (29.5%) > unidentified hydrolyzable N (20.0%) > hydrolyzable ammonium N (17.1%) > hexosamine N (3.5%) > nonexchangeable ammonium N (0.5%).

On the average, cultivation led to small increases in the proportions of total N as nonexchangeable ammonium N, Hydrolyzable N, hexosamine N, and hydrolyzable ammonium N, and to small decreases in the proportions as nonhydrolyzable N, amino acid N, and unidentified hydrolyzable N. The average percent losses of different forms of N on cultivation decreased in the order: amino acid N (43.0%) > nonhydrolyzable N (39.4%) > total N (36.2%) > total hydrolyzable N (35.2%) > unidentified hydrolyzable N (34.5%) > hydrolyzable ammonium N (28.6%) > hexosamine N (27.6%) > nonexchangeable ammonium N (0.2%).

¹ Journal Paper No. J-4819 of the Iowa Agr. and Home Econ. Exp. Sta., Ames. Project No. 1450.

² Research Associate and Professor in Soils, respectively.

Received for publication March 14, 1964. Accepted for publication April 27, 1964.