Residual Monuron, Diuron, and Simazine in a Vineyard Soil

Abstract

One year after the last of six annual applications of 3-(p-chlorophenyl)-l,l-dimethylurea (monuron) at 2.4, 3-(3,4-dichlorophenyl)-l,l-dimethylurea (diuron) at 2.4 and 7.2, and 2-chloro-4,6-bis(ethylamino)-s-triazine (simazine) at 1.0 and 3.0 lb/A in a furrow-irrigated vineyard on Warden silt loam, a bioassay using oats (Avena sativa L., var. Kanota) as the indicator showed that 1.6, 2.8, 10.6, 0.6, and 2.0 lb/A, respectively, remained in the surface 12 in of soil. Of the total, 62 to 89% was located in the surface 2 in and 86 to 100% was in the surface 4 in. Three years after the last of four annual applications of monuron at 7.2 lb/A, 0.8 lb/A remained in the surface 12 in.

Residues of atrazine, simazine, linuron and diuron after repeated annual applications in a peach orchard

“…Residues of herbicides were not detected below the 15 cm depth of the soil profile and the greatest concentrations were in the top 5 cm. This is in agreement with the results of Dawson et al (1968), Fryer & Kirkland (1970), and Bowmer (1972 who determined that residues of simazine, linuron and diuron were confined essentially to the top 15 cm of soil with the majority being found near the soil surface. Over shorter term experiments, similar mobility was observed for atrazine (Birk & Roadhouse, 1964;Burnside et al, 1969).…”

“…These results show that accumulation of herbicide residues did not occur after nine consecutive annual applications of relatively high rates of atrazine, simazine, linuron, and diuron to uncultivated orchard soil, although varying quantities of herbicide were detected in the late autumn of the last 3 years of treatment. Our observations confirm those of previous studies where high rates of simazine, diuron and linuron were applied to the same soil for 6 years and no significant accumulations of residues were observed (Dawson et al, 1968;Fryer & Kirkland, 1970;Bowmer, 1972). In addition, the present investigations indicate that atrazine should not pose a problem so far as residue accumulation is concerned even in situations where it is applied at high rates for many years.…”

“…The amount of herbicide measured the year following the last of six consecutive applications was between approximately 50 and 100% of the annual application rate for simazine and diuron in the studies of Dawson et al (1968) and for diuron in the experiments of Bowmer (1972). Fryer & Kirkland (1970) found that the annual carry-over of high rates of simazine and linuron averaged approximately 20% and 30%, respectively, of the amount applied.…”

“…Also in agreement with our experiments, other studies on repeated herbicide applications have indicated that diuron is more persistent than simazine. Bowmer (1972) found that diuron was approximately ten times more persistent than simazine on a soil of pH 4-6-4-7 but Dawson et al (1968) found a much smaller difference in persistence at a soil pH of 7-3.…”

Detection of triazine and urea herbicide residues by various characteristics of oat seedlings in bioassays

“…The effects of the herbicide residues are generally assessed by measuring differences in the dry weight of the oat seedlings 3-4 weeks after planting. This has allowed detection of triazine herbicides to minimum concentrations of approximately 005-0-10 ppm (Talbert & Fletchall, 1964;Dawson et al, 1968) and urea herbicides to 0I-0-3 ppm (Dawson, Bruns & Clore, 1968;Horowitz, 1970). Where chemical analysis has been used to confirm the results obtained by bioassay, there has been relatively close correspondence between the two methods (Santelmann, Weber & Wiese, 1971;Bowmer, 1972).…”