Influence of Soil Properties on the Phytotoxicity of Atrazine, Ametryne, Prometryne, and Diuron in Puerto Rican Soils

Abstract

Thirteen soils representing a wide range of physical and chemical properties were used in this study. Four herbicides including Atrazine, Ametryne, Prometryne, and Diuron were applied at a concentration series from 0.5 to 32 p.p.m. to each soil, with the exception of Caño Tiburones soil. Kanota oat (Avena sativa L.) was chosen as an indicator plant. ED₅₀  values were obtained for the various soil types. The result indicated that ED₅₀  values varied greatly with different soil types. Simple, partial, and multiple correlations were made among ED₅₀  values and different soil properties. It was found that the organic matter was the major soil property which contributed chiefly to the phytotoxicity of herbicides. A theoretical relationship between percent soil organic matter and p.p.m.w. of herbicides required for 50-percent fresh-weight reduction of oat was obtained for herbicide dosage-prediction purpose.