My Account: Log In | Join | Renew
Search
Author
Title
Vol.
Issue
Year
1st Page

Abstract

 

This article in SSSAJ

  1. Vol. 55 No. 3, p. 716-722
     
    Received: June 18, 1990
    Published: May, 1991


    * Corresponding author(s):
 View
 Download
 Alerts
 Permissions
 Share

doi:10.2136/sssaj1991.03615995005500030013x

Interactions of Microorganisms and Soil during Fenamiphos Degradation

  1. L.-T. Ou 
  1. Soil Science Dep., Univ. of Florida, Gainesville, FL 32611-0151

Abstract

Abstract

Enhanced degradation of a number of pesticides occurs in soils with a history of previous exposure to the chemical. Little is known, however, about the duration of enhanced degradation after a single field application of a pesticide or the microorganisms responsible for the enhancement. Soil samples collected 2, 3, and 4 yr after one application of the nematicide fenamiphos [ethyl-3-methyl-4-(methylthio)phenyl (1-methylethyl) phosphoramidate] at a rate of 4.48 kg ha−1 to an experimental site planted in potato (Solanum tuberosum L.) near Hastings, FL, were used to determine mineralization rates and total-toxic-residue (TTR) disappearance rates. Both mineralization rates and TTR disappearance rates in samples collected 2 and 3 yr after field application were enhanced compared with the corresponding control samples. Half-lives for TTR in soil samples collected 2 and 3 yr after field application of fenamiphos were 22 and 89 d, respectively, while half-life values for the corresponding control samples were 131 and 130 d. During a 70-d incubation period, 67.2, 27.8, and 9.8% of applied 14C-fenamiphos was mineralized in soil samples collected 2, 3, and 4 yr after field application, while 10.8, 11.5, and 9.5% of applied 14C-fenamiphos in the corresponding control samples was mineralized. Mineralization rates in soil collected 4 yr after field application were the same as in the control sample. Microorganisms capable of degrading fenamiphos could not be isolated from the soils. A mixed bacterial culture derived from soil collected 2 yr after the field application, in the presence of a small amount of this soil, however, did mineralize fenamiphos. Without the small amount of soil, the mixed culture did not mineralize the nematicide.

  Please view the pdf by using the Full Text (PDF) link under 'View' to the left.

Copyright © . Soil Science Society of America