Herbicide resistance challenges no-till

Date:01-14-2011

Weeds that stand up to glyphosate and other herbicides are causing some no-till farmers to do the unspeakable. They are going back to deep plowing and cultivating fields long in conservation tillage in order to control herbicide-resistant weeds.

That negates years of effort to build soil structure and organic matter as well as minimize erosion. The situation forces farmers to weigh one benefit against the other.

Strip-till and Lamar Black are synonymous in southeast Georgia. His farm near Millen, Ga., has been the showplace for the conservation-tillage practice almost since he started doing it in 1993. He was one of the first to grow rye as a cover crop and roll it down as heavy residue before planting corn, cotton and peanuts.

"We need to strip-till rather than no-till because we have to subsoil for a hardpan 12 to 14 inches deep," Black says.

The advantages of strip-tilling into the rye cover are numerous, he says. The rye helps control weeds of all types and adds soil tilth.

Georgia farmers' struggles with glyphosate-resistant Palmer amaranth are well documented. Black remains unconvinced that tillage is a solution.

"A lot of good would disappear in one year of tillage," Black says. "We were dealing with pigweed and other weeds before Roundup Ready crops came along. I may go back to a cotton system of using a hooded sprayer with MSMA and Cotoran. I'd rather do that than use a cultivator."

In addition, he'll probably use a preemergence herbicide like Reflex or Prowl. "I tried some this year and it looked good," Black says. "I'm using Ignite on LibertyLink cotton. Glyphosate is not used on peanuts. And on corn, there are other herbicides that can control pigweed."

Source: kfgo.com