Vol. 16—1962 - NorthEastern Weed Science Society

75
EFFECT;OFCOMPOSITIONANDVOLUMEOF ORGANICSOLVENTS
ONPERSISTENCEOF CARBAMATES IN SOILS
ANDONGRANULAR CARRIERS
(Abstract)
L. L. Danielson and W. A. Gentner !I
Earlier studies (Danielson et aI, Weeds 9:463-476. 1961) showed that
technical ethyl N,N-di-n-propylthiolcarbamate [EPTC]had long, intermediate,
and short persistence when applied in 40 g/A of acetone, No. 2 ruel oil, and
kerosene, respectively, in soil-incorporation studies.
Continuation of this research to evaluate the effect of volume of kerosene
on persistence of soil-incorporated EPTCshowed that persistence is
short at 40 g/A and increases as the volume decre .... s. The period of per.
sistence is not affected in the range of 40 to l38s/A.
Measurable but limited differences in persistence of soil-incorporated
isopropyl N-(3-chlorophenyl)carbamate [CIPC] and 2-chloroallyl diethyldithiocarbamate
rCDEe] were observed in greenhouse studies when the herbicidesvere
applied in 40 g/A of acetone, benzene, xylene, No. 2 ruel oil, and kerosene.
Persistence of soil-incorporated ethyl N,N-di-n-butylthiolcarbamate (R-1870)
was similar to that of EPTCwhen the same-solvents were used.
Fourteen liquid petroleum fractions were evaluated as carriers for
impregnation of EPTCon uncalcined 30/60 attapulgite applied as surface and
soil-incorporated treatments in greenhouse experiments. Persistence was
differentially affected by sol~ents and placement.
Four petroleum waxes were used at 2, 4, 8, and 16 olb/A in a continuation
of the study ()f petroleum fractions as carriers for impregnation of EPTCon
40 lb/A of 3O/60-mesh uncalcined granular attapulgitefor use as soil-surface
treatments. The persistence of EPTCwas differentially affected by the amounts
and composition of the waxes. Persistence of EPTCwas inversely related to the
amounts of waxes used.
11 Plant Physiologists, Crops Research Division, Agricultural Research Service,
u. S. Department of Agriculture, Beltsville, MaryIand.