1 Contribution from the All India Co-ordiiidled Research Programme on Weed Control, Directorate of Research, University of Agricultural Sciences, GKVK Campus, Banealore-560 C65 Karnataka.
The movement of four herbicides namely dicamba, 2,4-D, napropamide and simazine in red sandy loam soil was determined by growing maize and cucumber after 12 hours of application in plastic tubes of 22 cm (length), 3.5 cm (diameter) in 1978,83 and 85. Bioassay studies revealed that simazine, 2,4-D Na salt and dicamba moved upto 20 cm soil depth, where as napropamide moved upto JO cm. Top JO cm soil layer showed higher retention of herbicides ranging from 25 to 28% in 2,4-D, 25 to 33% in dicamba, 15% in napropamide and 23% in simazine. In all 45 to 54% of applied 2,4-D. 65 to 67% of dicamba, 25% of napropamide and 3°% of simazine were held in the soil column upto 20 cm depth
