EFFECT OF HERBICIDES AND WEEDS ON YIELD OF `EXCEL' SWEETPOTATO.

Abstract

Effects of herbicides and weeds were demonstrated by exposing `Excel' sweetpotatoes to a randomized complete block design of 3 replications of various treatments ranging from phytotoxity to no weed control in 1991 & 1992. Plots were either left unweeded, hoed clean or treated with herbicides (sethoxydim, clomazone, metolachlor, imazethapyr) or selective hand weeded to remove broadleaf weeds. Hand weeded treatments were hoed twice. After 120 days weeds remaining in each plot were cut at ground level, dried and weighed. At 125 days the plots were harvested. The roots were cured, graded and weighed. Weed dry weight ranged from zero to nearly 6.5 cwt/A. Weed dry weight as a % of total marketable sweetpotatoes ranged from zero to 34.5% in 1991 and zero to 19.8% in 1992. Competition from grasses reduced sweetpotato yield more than broadleaf weeds. Total marketable sweetpotato yields ranged from zero to 426 cwt/A in 1991 and from 210 cwt/A to 289 cwt/A in 1992.