Effect of pH on Metribuzin Activity in the Soil

Abstract

Metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazine-5(4H)one] applied preemergence resulted in increased phytotoxicity with increasing soil pH. In the field, fall panicum (Panicum dichotomiflorumMichx.) control, number of dead corn (Zea maysL.) and soybean [Glycine max(L.) Merr.] plants, and crop injury ratings increased, and plant height and grain yield decreased as the soil pH increased. In the greenhouse, corn and soybean grown in soil showed decreased dry weights due to metribuzin as pH increased. By contrast, the pH response to metribuzin was not evident in nutrient-sand culture, indicating that, in soil, pH affected the availability of metribuzin for plant absorption.

The effect of soil ph on the activity of oryzalin and metribuzin on five common weeds in no‐till crop production

“…This agrees with Ladlie et al (14) who showed that the activity of metribuzin was significantly less at pH 4.6 than at 6.7. In the opinion of Bailey and White (5) the surface pH level is probably the most important soil property in determining the activity of basic organic compounds such as metribuzin.…”

“…Considerable work has shown that many herbicides exhibit better activity at higher soil pH, particularly the triazines (12,13,14) and dinitroanilines (9,10,11,15). Hartwig (8) found with atrazine and simazine that control of fall panicum (Paniem dicotomiflorm Michx.)…”

Applications of Metribuzin for The Control of Rigid Brome (Bromus rigidus) in No-Till Barley Crops of Southern Australia

“…The differences in the level of barley damage reported between Warooka and Rudall locations at the highest rate of metribuzin (270 g/ha) are likely to be due to lower clay and organic matter content at Rudall (Table 1). These soil characteristics have been shown to be associated with increased metribuzin activity and crop phytotoxicity (Ladlie et al 1976;Blackshaw et al 1994). In contrast, the heavy textured soil at Warooka is likely to adsorb and bind more metribuzin, reducing its influence on the crop.…”

Methiozolin sorption and mobility in sand-based root zones

“…Sorption to soil also influences herbicide soil mobility. As a herbicide becomes sorbed to soil colloids, it generally becomes less mobile in the soil . Uncharged herbicides with high water solubility and low K ow tend to be poorly sorbed to soil and are therefore more mobile owing to their greater affinity for the water phase.…”