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 Dubey, H. D. Articles by Rodriguez, R. L. Search for Related Content PubMed Articles by Dubey, H. D. Articles by Rodriguez, R. L. Agricola Articles by Dubey, H. D. Articles by Rodriguez, R. L.

Effect of Dyrene and Maneb on Nitrification and Ammonification, and Their Degradation in Tropical Soils¹

ABSTRACT

The effect of 2,4-dichloro-6-(o-chloroanilino)-s-triazine (dyrene) and manganese ethylene bisdithiocarbamate (maneb) at 0, 15, 60, 240, and 960 ppm on nitrification of 100 ppm applied NH₄-N, and on ammonification of soil nitrogen, and the degradation of these fungicides, were studied in a lateritic clay and a fertile loam incubated at 24C for 16 weeks.

Inhibition of nitrification by the fungicides was lesser and of shorter duration in the rapidly nitrifying loam than in the slow nitrifying lateritic soil. The chemicals inhibited the ammonia oxidizing bacteria but not the nitrite oxidizing bacteria. Maneb was several times more toxic to the nitrifying organisms than dyrene, and its effect lasted even after the chemical was degraded. Ammonification was inhibited only at 960 ppm of the fungicides. There was no synergistic effect with regard to inhibition of nitrification or ammonification when the soil received both the fungicides. The fungicides were degraded faster in the rapidly nitrifying soil than in the slow nitrifying soil. Maneb was decomposed earlier than dyrene.

¹ Contribution from the Department of Agronomy and Soils, Agr. Exp. Sta., University of Puerto Rico, Mayaguez Campus, Río Piedras, Puerto Rico. This work was supported in part by the Expt. Sta. Hatch project H-189 and the Regional project S-62.

² Associate Soil Microbiologist.

Received for publication September 30, 1969. Accepted for publication February 12, 1970.