Hoard's Dairyman Editorial: Crop rotation protects us from mutant weeds

Hoard's Dairyman Editorial: Crop rotation protects us from mutant weeds

Nature always has a way to restore balance. In the chase to capture the highest possible returns, countless crop farmers turned a blind eye to Mother Nature and planted continual rotations of corn, soybeans, or a combination of the two. Now weeds are having their revenge as their herbicide-resistant offspring are besieging corn and soybean fields. Thankfully, those who milk cows for a living implement more diverse crop rotations.

High market prices have caused farmers to sprint in order to plant more corn and soybeans. Since 1991, there has been a 27 percent gain in harvested soybean acres while corn has exploded by 22 percent during the past decade. Meanwhile, growers placed a greater reliance on the combination of genetically modified seeds and herbicides to control weeds. Little attention was given to highly recommended refuge crops. With little variation in strategy, mutant weeds had their window to proliferate. The results are staggering.

The most popular herbicide choice, glyphosate, now has 13 known weeds that repel its mode of action throughout the U.S., reports the International Survey of Herbicide Resistant Weeds. It doesn’t stop there. Worldwide there are 50 weeds known to have resistance to one herbicide; 36 resistant to two herbicides; and 14 resistant to three or more.

All of us who grow crops need to become much more selective in how we use and rotate herbicides . . . with the key word being rotate. A three-way crop mix is far preferred to mono- or dual-planting options as it provides greater diversity in weed management chemistry options.

To that end, dairy producers are better suited to keep herbicide-resistant weeds at bay. On average, our readers cropped slightly over 500 acres last year. Corn led the list being raised on 83 percent of farms. It was followed closely by alfalfa, 76 percent; soybeans, 34 percent; oats, 28 percent; and then followed by a variety of other crops.

Alfalfa and other forages provide a great chance to naturally keep weeds at bay. The advice from our founder is as good today as it was when he penned it:
“There is one advantage in alfalfa in this respect. It remains longer in growth and the cutting of three crops a year is death on weeds.” — W.D. Hoard

While other farmers have succumbed to the temptation to grow only corn and soybeans, we will be best served to keep alfalfa and grasses in the mix. It makes for a better ration and it will keep resistant weeds from multiplying on our farms.

This editorial appears on page 238 of the April 10 issue of Hoard's Dairyman.