REDUCED INPUT CORN WEED-CONTROL - THE EFFECTS OF PLANTING DATE - EARLY-SEASON WEED-CONTROL, AND ROW-CROP CULTIVATOR SELECTION

Concerns of pesticide detection in ground and surface water and the desire to lower external or off-farm inputs have renewed interest in mechanical weeding to reduce herbicide use and weed control costs. Field research was conducted to evaluate weed control using S-tine, minimum-till, rolling, and C-shank row-crop cultivators in corn (Zea mays L.) planted 25 April, 5 May, and 15 May. Rotary hoeings or a 10-in. band of atrazine plus metolachlor PRE herbicide were used for early season in-row weed control. The field had a silt loam soil and high annual weed pressure and the previous crop was corn. Weed control was excellent with banded herbicide at all planting dates. Weed control with the rotary hoe was less than that of the banded herbicide but improved as planting was delayed. Banded herbicide resulted in better weed control, higher corn yield, and less corn population reduction than rotary hoeing. Weed control, corn population reduction, and corn yield were similar for all row-crop cultivators. Early planted corn treated with banded herbicide and cultivated twice gave the highest economic return.