INITIAL WEED-FREE PERIOD AND SUBSEQUENT YELLOW NUTSEDGE POPULATIONS DENSITY AFFECT TOMATO YIELD

摘要

An experiment was conducted to determine the effect of yellow nutsedge (Cyperus esculentus L.) times of emergence and densities on tomato (Lycopersicon esculentum Mil!). Densities of 0, 25, 50, and 100 yellow nutsedges per m2 were planted in tomato plots at 0,1, 3, 5, 7, 9,11, and 13 weeks after transplanting the crop (WAT). Tomato yield decreased as yellow nutsedge emerged earlier in the season and as nut-sedge density increased. Large and extra large fruit yield was reduced by 50% when yellow nutsedge emerged at densities between 50 and 100 plants per m2 and interfered with tomato season-long. Total marketable yield loss was 25, 55, and 65% whon yellow nutsedge emerged at the densities of 25, 50, and 100 plants per m2, respectively, and interfered with the crop during the entire season. At densities of 25 to 50 yellow nut-sedges per m2, yellow nutsedge suppression for the first 8 WAT would be necessary to prevent >5% total marketable yield loss.