The Persistence of Atrazine, Ametryne, Prometryne, and Diuron in Soils Under Greenhouse Conditions

Abstract

The persistence of Atrazine, Ametryne, Prometryne, and Diuron in 13 Puerto Rican soils was studied under greenhouse conditions, using oats (Avena sativa L. var. Kanota) as the bioassay plant. Judging from the data obtained from six successive croppings of oats, Diuron was the most persistent herbicide in most soils while Prometryne was the least so. Ametryne and Atrazine were intermediate in persistence; however, the former was found to be more persistent than the latter in most of the soils studied. Of all the soil components or properties studied, organic matter appeared to be the one most highly related to the persistence of the four herbicides. The degree of herbicide persistence was lower in soils having a high organic matter content. This may be attributed to a greater microbial detoxification capacity associated with a higher organic-matter content of the corresponding soil.