Metolachlor, applied to the surface of leaching columns as dicalcium p
hosphate tablets, was recovered over a period of 25 d compared with 2
and 3 d for emulsifiable concentrate and granular formulations, respec
tively. In similar studies, approximately 27% of napropamide was recov
ered from tablets during the same period. Adding an adjuvant to the na
propamide tablet mixture increased the recovery rate to 55%. Tablet ha
rdness and size had little effect on the release rate of napropamide.
Tablets containing 4% al napropamide released greater amounts of herbi
cide at a single collection period than did tablets containing 1% ai.
Adding an adjuvant to the napropamide tablet mixture significantly imp
roved Italian ryegrass control in the area adjacent to herbicide place
ment.