Ask Don Garlow about his days "walking beans" and the Concordia, Kan., farmer's back almost aches in memory.
It used to be the only practical way to rescue a soybean field from weeds was by walking the rows and yanking the invaders by hand.
"We don't walk beans anymore," Garlow said. "We have a better way."
Now, in testimony to the wonders of biotechnology, the same fields are pictures of uniformity. Rarely do weeds take hold where genetically modified crops — laboratory-designed to withstand the powerful herbicides that make history of common weeds — have been planted.
That wonder has been good not just for farmers such as Garlow, a study from the National Research Council reported Tuesday, but also for the environment. Cleaner water. Less soil erosion. Lower fuel consumption. Smaller doses of carbon dioxide belched into the atmosphere.
The report, though, warned about too much of a good thing. It said the overuse of the biotechnology nine of every 10 U.S. acres planted in corn or soybeans is now home to genetically tinkered plants is whittling away its advantages.