Weed management in organic crop production is not for the faint-hearted or for wimps. Even in a good year, organic production is risky, and 2011 has highlighted those risks, says Carroll Johnson, USDA-ARS in Tifton, Ga.

Weed control is the major limiting factor in organic farm production, says Johnson, especially in peanuts. “We’ve been working on this since 2004, but this is the first time we’ve tried it at the Expo site,” he said during this summer’s Sunbelt Ag Expo Field Day held in Moultrie, Ga.

“Our intent is to try and capture some of the increasing demand for organic food staples, especially organic peanut butter. Most of these type products now are imported from other countries. There’s no reason why we can’t grow organic peanuts and sell organic peanut butter in Georgia — that’s our goal,” says Johnson.

The Expo demonstration was designed to show the feasibility of organic crop production and techniques of weed management with an emphasis on peanuts. Millet also is part of the demonstration, being grown in rotation with peanuts.

“As everyone is painfully aware, the 2011 growing season has been an absolute nightmare up to this point,” said Johnson during the first week of July. “Unusually hot temperatures created a terrible set of circumstances prior to establishing a stand. We have routinely had soil temperatures 2 inches deep that are as high as 117 degrees F. If you try to plant untreated seed — which is what you do in organic farm production — in soil that hot, you can water it all you want and it doesn’t do much good.”

Johnson was making his third attempt to plant at the Expo site since mid-May.

“We finally were able to get it in, but we ran out of untreated peanut seed. In our first attempt at planting organic peanuts here, we had less than a 20-percent stand,” he says.

One of the concepts of weed control being used in the trial is a tine weeder, says Johnson. “It’s an imported implement from Austria, and the key to weed control in any crop is to get a good stand, optimal row spacing, optimal seed placement and frequent and intense cultivation.

“Peanuts will tolerate abuse from this implement. The ideal stage for beginning cultivation for organic peanut production is at cracking. If you see any weeds at all, it is too late.”

Weed control in organic crop production is based on an integrated system of cultural, mechanical and physical weed control efforts, he says. Reliance on a single form of weed control, says Johnson, will result in failure.