Efficacy of mechanical cultivation with and without herbicides in broccoli(Brassica oleracea), snap bean (Phaseolus vulgaris), and sweet corn (Zea mays)

Five cultivation implements (two flex-tine cultivators, brush hoe, and roll ing and shovel cultivators) were evaluated for weed control and effect on b roccoli, snap bean, and sweet corn yield. Each implement was used alone or in combination with flex-tine cultivators. Standard broadcast herbicide tre atments were: broccoli, metolachlor at 2.3 kg ai/ha posttransplant; snag be an, metolachlor preemergence (PRE) at 2.3 kg ai/ha followed by fomesafen po stemergence (POST) at 0.4 kg ai/ha; sweet corn, atrazine at 1.1 kg ai/ha pl us metolachlor at 2.3 kg ai/ha PRE. In the snap bean trials, an additional treatment consisted of metolachlor at 2.3 kg ai/ha PRE applied in a 25-cm b and over the crop row followed by fomesafen POST at 0.4 kg ai/ha directed a t the crop row, with a subsequent shovel cultivation. In the sweet corn tri als, all cultivation treatments received an application of atrazine at 1.1 kg ai/ha plus metolachlor at 2.3 kg ai/ha PRE in a 25-cm band over the crop row. In broccoli, weed control and yields with all cultivation treatments were comparable to those with broadcast herbicide. In snap bean, flex-tine cultivators failed to control weeds and prevent yield reductions compared t o the broadcast herbicide treatment. When either the brush hoe or the shove l cultivator was preceded by flex-tine cultivation, weed control and snap b ean yield were comparable to those with broadcast herbicides. Banded herbic ides followed by shovel cultivation also controlled weeds and prevented yie ld reductions. In sweet corn, banded herbicides controlled in-row weeds, an d despite variable between-row weed control, all cultivation treatments yie lded as well as the broadcast herbicide treatment. Relative performance of the cultivators was influenced by soil type and rainfall as well as crop ca nopy characteristics.