The degradation of 2,4-D in forest litter

Abstract

These studies have shown that 2,4-D is rapidly degraded in forest litter and that the rate of degradation varies with the type of litter, herbicide formulation and the presence of DDT. The degradation of 2,4-D varies slightly in litter from different vegetation types when incubated under similar environmental conditions. Greater variation in herbicide degradation rates may be expected in the field; but this will be due primarily to differences in the site microenvironment, rather than inherent differences in the litter.Various formulations of 2,4-D are degraded at different rates in forest litter although we believe this to be more a function of constituents of formulation than a direct effect of the technical acid, salt or ester.Finally, these experiments have shown that up to 4 gallons per acre of diesel oil has little or no effect on the decomposition of 2,4-D isooctyl ester, while 1 lb./A. of DDT appears to stimulate herbicide degradation.

Relative persistence of di‐and tri‐chlorophenoxyalkanoic acid herbicides in Saskatchewan soils

“…It is almost impossible to calculate the rates of herbicidal breakdown from these studies; although an exception is that of Kirkland & Fryer (1972), who observed the soil half-life times for dichloprop and fenoprop in moist soils at 23°c to be approximately 10 days. These times are in good agreement with the present data (Table 3), Norris (1966) andFoster &McKercher (1973) used [i*C] labelled 2,4-D and 2,4,5-T in their experiments to facilitate analysis. Breakdown of both chemicals was noted in forest litter soil by Norris (1966), with almost 90% ofthe 2,4-D, but only 23% of the 2,4,5-T, being degraded in 2 weeks.…”

“…These times are in good agreement with the present data (Table 3), Norris (1966) andFoster &McKercher (1973) used [i*C] labelled 2,4-D and 2,4,5-T in their experiments to facilitate analysis. Breakdown of both chemicals was noted in forest litter soil by Norris (1966), with almost 90% ofthe 2,4-D, but only 23% of the 2,4,5-T, being degraded in 2 weeks. The studies by Foster & McKercher (1973) indicated that in moist Saskatchewan soils at 26°C the half-life times for ["*C]2,4-D ranged from 14 to 41 days.…”

“…Although these chemicals are applied postemergence to weeds, a part of the treatment does come into contact with the soils whence such residues are degraded by microbiological processes (Alexander & Aleem, 1961;Audus, 1964;Loos, 1975). Many studies have been conducted on the soil persistence of 2,4-D (DeRose & Newman, 1947;Brown & Mitchell, 1948;Newman, Thomas & Walker, 1952;Burger, MacRae & Alexander, 1962;Norris, 1966;Altom & Stritzke, 1973;Foster & McKercher, 1973;Plumb, Norris & Montgomery, 1977), and 2,4,5-T (DeRose & Newman, 1947;Newman et al, 1952;Burger et al, 1962;Norris, 1966;Altom & Stritzke, 1973;Foster & McKercher, 1973;Plumb et al. 1977;Walker & Smith, 1978).…”

Adsorption of the Herbicide 2,4‐d on Goethite

“…The chemical is relatively quickly degraded by soil micro-organisms, but complications may arise through adsorption on to soil articles or mineral soils very low in organic matter. Although there has been much work on the interaction between 2,4-D and clay minerals (Frissel, 1961 ;Weberet al, 1965 ;Bailey and Rothberg 1968), soil organic matter (Norris and Greiner, 1967;Haque and Sexton, 1968) and activated charcoals or carbons (Weber et al, 1965;Ward and Getzen, 1970), there has been no systematic study of the interaction with oxide minerals, which also constitute an important fraction of many soils (Bailey and White, 1970). Hence, the adsorption of 2,4-D on to a well-characterized iron oxide, goethite, was studied here.…”

Phenoxy Herbicide Residues and Their Persistence

“…Norris (1966) and Norris and Greiner (1967) of forest trees: Douglas; fir, big leaf maple, vine, maple, Ceanothus and ret; alder. These little samples were treated with 3 lb/acra equivaleat of (1) and 3% at 70, 85 and 100 o F, respectively.…”