At the Farm Science Review demonstration plots, a field appears as a checkerboard: thriving green crops beside squares of shriveling beige stalks.

This was not a farmer’s bad luck. Instead, the field was intentionally sprayed with 13 different weed killers to show their effects on various crops, as well as the consequences of herbicides that drift from their intended target.

“Would a farmer do this to a field? Absolutely not,” says Harold Watters, an agronomy field specialist with Ohio State University Extension. “The purpose is to share what can happen when things don’t go as planned.”

At least seven different types of weeds common in Ohio are resistant to one or more herbicide that previously killed them, says Mark Loux, an OSU Extension weed specialist. Waterhemp, one of the more rapidly spreading weeds in Ohio, is particularly troublesome because of its resistance to so many weed killers — including glyphosate.

Watters and Loux will be among a team of OSU Extension experts who will discuss issues relevant to farmers, including weed killers, cover crops and nutrient management, during the 56th annual Farm Science Review, to be held Sept. 18-20 at the Molly Caren Agricultural Center near London, Ohio. The annual agricultural trade show is sponsored by OSU’s College of Food, Agricultural and Environmental Sciences (CFAES).

For farmers, weeds are more and more of a vexing problem, as the herbicides that used to kill them no longer work. Just about every year, at least one weed in Ohio is shown to survive a herbicide that used to destroy it, Watters explains.

The increased use of a herbicide often causes the target weed to become resistant to it, much the same way increased use of antibiotics has led to some of them no longer being effective against certain bacterial infections.

Besides illustrating the effects of various herbicides, the demonstration plots at the FSR will show how nutrient levels within a field can differ significantly.

“I can look across a field and see waves of differences,” Watters says.

One portion of a field might be low in phosphorus, while another section has enough of it — information a farmer needs to know to ensure no portion of a field is treated with too much of the key nutrient. Those differences underscore the need for a farmer to apply different rates of fertilizer or manure to different parts of a field growing the same crop to prevent the potential for runoff of those nutrients into an aboveground water source, Watters adds.

Tickets for the FSR are $7 online, at participating agribusinesses and county OSU Extension offices; and $10 at the gate. Children ages 5 and under get in free. Hours for the event are 8 a.m. to 5 p.m. Sept. 18-19, and 8 a.m. to 4 p.m. Sept. 20. For more information, visit fsr.osu.edu.

Source: OSU