A recent study by Virginia Polytechnic University educators sheds some light on the true cost of no-till weed control. Besides looking at herbicide costs, the study took a close look at the role that manure application rates have in determining weed-control costs.

Data was collected from 143 fields where corn was grown by 36 farmers in Virginia’s Shenandoah Valley in 2001. Analyzed by extension agents R. Clark and T. Stanley along with weed scientist S. Hagood, the data indicated that no-till weed-control costs about $3.50 more per acre than in tilled fields. However, the tilled land did not include any cost for tillage, which would more than offset this additional cost. Weed-control costs averaged $51.95 for no-tilled ground and $48.43 for tilled land.

While the majority of farmers spent between $40 and $60 per acre for weed control in corn, there was a strong relationship between the number of passes across the field with spraying equipment and weed-control costs per acre.

Rotations Vs. Continuous Corn

The rotated corn was defined in this study as not generally being in corn for more than 3 years while continuous corn was generally grown 3 or 4 years in a row.

No-tillers who rotated crops averaged $43.88 per acre in weed-control costs while farmers who no-tilled continuous corn averaged $58.94 per acre in weed-control costs. These figures are based on actual costs, including custom-application costs, a technology fee of $6 per acre for Roundup Ready corn and a $6 application fee for each pass…