Better Weed Control In Organics

Weeds are the primary enemy of the organic peanut farmer,
but a new control regime is finally achieving success.

By Amanda Huber

Organically grown products are more in demand than ever before. Be it for health reasons or to be sure you are eating something in its purest form or just going along with the trend, organically grown fruits, vegetables, animal-based products and, now, even row-crop commodities line the shelves of the grocery stores.

Naturally, this has lead to an increased interest in growing organic peanuts.

Organic farmers face many of the same problems that conventional farmers face. The difference is that organic farmers have fewer solutions to combat those problems. For instance, the primary limiting factor to successful organic peanut production is weed control.

But organic farmers, like all farmers, do not give up easily. Their dedication to producing crops through sustainable methods gives new meaning to the phrase, “If there’s a will, there’s a way.” They study, experiment, toil, glean bits of information from experts and other growers – deeply appreciating every effort made by others to help them grow things just a little bit better than they did last year.

Enter Relinda Walker, the daughter of a traditional row-crop farmer, who never imagined that she would become a farmer.

“It really started when I developed a passion for food and a desire to be part of a healthier food system, which lead me back to agriculture,” she says.

On A Mission
Today, Walker Farms is a certified organic farm with 40 cultivated acres of Vidalia onions, melons, peanuts, various organic vegetables, rye and soybeans and lots of cover crops.

“These 40 acres are part of the land my grandfather, Frank Lafayette Walker, bought in 1925 and which my father, Frank Alston Walker, farmed for more than 60 years,” Walker says.

“My dad was recognized for both successful production and good stewardship of the land,” she says. “He was also among the first in the region to grow watermelons and cantaloupes commercially, and his roadside sales attested to the quality of these crops.”

Walker says the evolution of Walker Farms to an organic enterprise began when she returned to the farm to start growing specialty produce for restaurants, stores and local customers. To her, Walker Farms is both a mission and an enterprise, and she strives to balance the two.

“The process has been one of intensive learning: from my father about the basics of growing and from a remarkably generous network of farmers, researchers and Extension folks willing to share experiences and work together to improve our ways of growing.”

Growing And Learning
In 2005, the farm was officially “certified organic.”

Her goal is to make Walker Farms sustainable as a farm and as a business and to have her farming contribute to a healthier environment and a strong regional food system.

As sometimes happens when you are trying to learn something new, Walker became involved with organizing workshops and field days as the South Georgia program coordinator of Georgia Organics, a role she took on in late 2002.

“I was growing in my own knowledge and facilitating the learning of others interested in organic and sustainable farming methods,” she says.

Through this, Walker Farms became a test ground for research in organic Vidalia onions, weed management, no-till vegetable production, improved use of cover crops and commercial organic peanut production.

Enter Carroll Johnson, a weed scientist with the United States Department of Agriculture’s Agricultural Research Service based in Tifton, Ga., at the Coastal Plain Experiment Station who works extensively with peanuts, both conventional and, now, organic.

“Organic peanuts is really a work in progress.” Johnson says. “There are some real challenges we are facing, but we’ve come a long way.”

Teaming Up Against Weeds
Weed control has come a long way because farmers like Walker and researchers like Johnson team up to find a better way.

“We can manage weeds much better now than we could just three years ago,” Johnson says.

On Walker’s farm the primary weed problems are pigweed, morningglory and evening primrose. She also has a little wild mustard and nutsedge in some plots.

“In general, tillage and hand-weeding have been the order of the day for organic peanut efforts, except for my no-till experiment, which was overwhelmed by nutsedge,” Walker says.

However, tillage wasn’t as useful as it could be until they found the right implement to use.

“One of the difficult things was learning how to cultivate and what implements work best,” Johnson says.

He also says one of the best implements they have found is more often used in Europe. It is the flex-tine cultivator or weeder, which is a light-weight, high-speed cultivator with multiple rows and gangs of adjustable spring tines. Tines in the row middle are set with aggressive tension, while tines over the drill are adjusted to less or no tension, depending on the stage of crop growth. Essentially, the tines are tough, but still flexible.

“They do not disturb the soil as much, but they vibrate, controlling small seedlings and non-emerged weeds,” Johnson says. But, after finding the right implement, there was still a matter of learning how and when to cultivate.

“If you see weeds, it is really too late. You have to cultivate just before weeds come up,” he says.

“A lot of this is nothing really new. It’s the way weeds were controlled 50 years ago, but we’ve had two or three generations since then,” Johnson says.

Success For The First Time
Putting the implement and know-how together, Johnson says the best regime is the tine weeder right at true “ground crack,” cultivating over the seed drill and also in the middles. This was repeated one week later when peanuts were just beginning to come up.

“The next week we had to adjust the tines over the peanuts. Then we cultivated once a week for seven weeks, getting less aggressive each time and lifting tines over the row,” he says.

The weed control regime does not eliminate hand weeding, but makes it easier and less costly.

Walker says in the beginning, she hoed weeds that were missed in the row just one time, and later just hand-pulled weeds for probably four times over the season.

“The hand weeding was not onerous, and it got easier and more casual as the season progressed,” she says. “The plot was very clean.”

But Johnson says the flex-tine cultivation is not doing as good a job on the large-seeded broadleaf weeds such as cocklebur, sicklepod and morningglories. “The major weed problems we were going to have were annual grasses, and this weeder did a good job on those.”

Walker says the weed control provided through Johnson’s research was a great improvement over previous methods.

“It’s the first time we were actually successful,” Walker says. “I expect to follow the same regime for the most part, although Carroll [Johnson] has some ideas he wants to experiment with.”

New Variety Another Asset
Besides weed control, Walker says another key issue in organic peanut production is simply getting a stand.
“Without seed treatments, getting a good stand can be a problem,” she says. “This year we addressed our insufficient stand by going back over and planting additional rows, effectively twin rows.”

But Walker says the new variety, Georganic, developed by peanut breeder Corley Holbrook at the Coastal Plain Experiment Station in Tifton, has a disease resistance package that really helps.

“I used no fungicides at all, not even organically approved products, and my crop was generally healthier than the oft-sprayed conventional crops of my neighbors,” Walker says.

Walker’s rotation puts peanuts behind her organic Vidalia onion crop, which she says is pretty intensively managed.

“I think that’s a good strategy and will also put in a crop this year after onions,” she says.

Walker got a yield of just over 3,000 pounds per acre for her peanuts in 2007, a feat she says she would be pretty happy to repeat.