Concern about the effects of pesticides on the environment and the desire to reduce purchased inputs are stimuli to reduce herbicide use. Field research was conducted at two locations for two growing seasons to identify integrated weed management practices in corn that are effective and economical. Weed control treatments included PRE application of a herbicide mixture of 1.8 kg ai ha−1of atrazine plus 2.2 kg ai ha−1of metolachlor alone, this mixture broadcast or band-applied at a reduced rate in combination with mechanical weeding, and mechanical weeding alone. Weed control, corn yield, and economic returns were generally higher in treatments combining herbicides and mechanical weeding than those using only mechanical measures. Without herbicides, timeliness of rotary hoeing was critical. Herbicide use can be reduced 50 to 75% in integrated systems with minimal risk of yield loss due to uncontrolled weeds.

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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 rowcrop 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. Research Question Corn producers seek weed control methods that reduce herbicide use to minimize potential surface and groundwater contamination. Mechanical weed control is not new, but has received little attention following the advent of highly selective and effective herbicides. The objective of this study was to compare two early season weed control strategies (banded herbicide and rotary hoeing), followed by two cultivations with four row‐crop cultivator models, over a range of corn planting dates in a reduced tillage system. Literature Summary Mechanical weeding was a standard practice in corn production until recently. Even when weeds are controlled with herbicides, cultivation often improves corn yield. Planting date and soil tillage affect cropweed interactions. Delayed planting allows corn to germinate after the peak germination period of some weed species and also enhances corn's competitiveness because seeds are planted in a warmer soil. Rotary hoeing and band‐applied herbicides try to control early emerging in‐row weeds, which is the row‐crop cultivator's main weakness. Iowa data show that banded herbicides, complemented with cultivation, reduce chemical inputs by two‐thirds without decreasing corn yields. Relatively little research on row‐crop cultivation has been done in recent years. Study Description The study was conducted in 1990 and 1991 at the University of Wisconsin Arlington Research Station on a Plano silt loam soil. Corn was planted in 30‐in. rows and cultivated twice. The study was set up as a complete factorial with three factors. Factor 1. Early season in‐row weed controlBanded herbicide (applied preemerge in 10‐in. bands)Rotary hoeing (twice) Factor 2. Planting date25 April5 May15 May Factor 3. Row‐crop cultivator design S‐tineMinimum‐tillRollingC‐shank Applied Questions How do banded herbicide and rotary hoeing compare as methods to lower corn weed control inputs and does date of planting...

Many fanners are reevaluating their weed management practices to see if their use of herbicides can be modified. Since 1989, we have done work on reduced herbicide rates in com. A total of 11 trials with preemergence herbicides and one with preplant incorporated products have been done. A trial in soybeans with preemergence and postemergence products was done in 1991. We achieved a reduced use of chemicals by either lowering the rate of a broadcast, preemergence or postemergence spray or by applying a preemergence herbicide in bands over the crop row.