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Combating pigweed takes thought and management

RICHARD JAMESON Brownsville Tenn says dealing with Palmer pigweed is one of the most stressful things hersquos ever had to do
<p>RICHARD JAMESON, Brownsville, Tenn., says dealing with Palmer pigweed is one of the most stressful things he&rsquo;s ever had to do.</p>
&ldquo;My father couldn&rsquo;t stand to see a weed out there. But, with resistant pigweed, I don&rsquo;t think &lsquo;control&rsquo; is the appropriate word. What we do is work to manage it &mdash; and we&rsquo;re doing a good job. But it&rsquo;s a headache.&rdquo;

Ride along with Richard Jameson and you don’t see many weeds in his fields. He’s quick to point them out, though: the dreaded Palmer amaranth/pigweed in field borders, sprinkled through ditches, popping up occasionally in soybean rows.

Fighting the glyphosate-resistant weed now ranks as his top agronomic frustration in soybeans and cotton.

“I sprayed three times,” he says. “And I chopped them. I pulled them when I saw them. Then I gave up. I read that weed specialists say we should have zero tolerance for pigweed.

“That’s hard — it’s a difficult thing to do,” says Jameson, who farms 2,400 acres near Brownsville, Tenn.

He’s going to try something new to perhaps minimize the weed’s encroachment in his fields. He has signed up for the Conservation Stewardship Program that’s administered by the Natural Resources Conservation Service.

Five-year contracts

It features five-year contracts, with annual payments for certain conservation practices. He chose to work with cover crops and ditchbank stabilization.

“Right now, I’m looking at a mixture of cereal rye, winter wheat and a legume, such as crimson clover,” Jameson says. “Cereal rye has some allelopathy on weeds. A biochemical in its roots supposedly has an effect on weeds.

“If that’s true, that will discourage the germination of pigweed seed. If you ask why plant cover crops, do you want to add nutrients through legumes? Do you want to get soil in better shape? The answer is yes. But, for me, the number one reason is to help manage weeds.”

He’ll plant the cover crops behind corn. Wheat can also help with pigweed, he thinks.

Wheat thwarts pigweed

“It’s another reason to plant wheat. You won’t see pigweeds come up in a good thick stand of wheat. When you combine wheat, you won’t see pigweed. What we do see is marestail.

“When we spray Harmony, about March 1, we add 3 ounces of Clarity to take care of the marestail. The main thing about wheat is that it helps to manage glyphosate-resistant pigweeds. It’s another cover crop that’s going to help.”

With a pigweed here and a pigweed there, not even the pickiest zero-tolerance agronomist could call Jameson’s fields overrun by it. But he, like most farmers, prefers perfectly clean fields that pose less risk to producing good yields.

“My father couldn’t stand to see a weed out there,” he says. “But, with resistant pigweed, I don’t think ‘control’ is the appropriate word. What we do is work to manage it, and we’re doing a good job. It’s just the headache that gets me.

“I think we could go broke if we thought we had to get every pigweed. It’s amazing, growing as fast as it does and producing hundreds of thousands of seeds. That’s a really formidable foe. We used to deal with weeds like cocklebur and sicklepod. They were bad enough, but nothing like this.”

Makes everything more difficult

In fact, pigweed makes just about everything more difficult, Jameson says.

“It’s the most stressful, anxiety-producing thing I have to deal with. We spend a lot of time on it. The crop consultant gets involved with it a lot.

“It’s toughest in cotton, so that’s a good reason to rotate to corn and soybeans. But, it’s tough in soybeans, too. The rotation gives us a chance to work on it some with different herbicide chemistries.”

He thinks corn provides the best chance to fight pigweed with herbicides.

“Corn has really good herbicides that do a fine job on pigweed. Plus, if you get a good stand, that shades the ground, and helps control it.

“Pigweed has to have light to grow. Once the corn dries down and sunlight hits the ground, pigweed comes on up late in the season. That’s why some farmers here spray fields in mid-September to keep it down.”

Rains helped with residuals

Frequent rains in 2014 may have actually helped control Palmer pigweed, Jameson thinks.

“It rained enough that we got the residual herbicides into the soil where they could go to work. That helped a lot.

“If it doesn’t rain and is bright and sunny, residuals will begin to degrade within three to five days. You need rainfall or irrigation to get the residuals into the top inch of soil.”

A no-till adherent since 1985, Jameson plants soybeans on 15 inch rows, corn on 30 inch rows, and cotton on 38 inch rows.

He shoots for a relatively high plant population. “Getting a good stand is critical, so the plant canopy will shade the ground,” he says. “When the ground is shaded, that really helps with pigweed management. We have to do everything possible to help ourselves with this.”

Just prior to planting soybeans or cotton, he applies  a burndown spray of gramoxone plus a residual herbicide. “That’s typically in late April or early May. Pigweed germinates at soil temperatures of 62 degrees or above. That’s how we time it.”

When the crop emerges, he comes back with another residual herbicide. At 18 days after emergence, he applies another residual, along with an over the top contact herbicide.

“Don’t wait until day 21 or 24 — you have to go in there at the right time, when the weed is small. Pigweed grows so fast that you can’t get distracted and let it go for a few days. Timing is everything. And you may have to do it several times.”

A bit more than half of Jameson’s acreage can be irrigated with center pivots. In this wet year, he only ran them twice, and wonders if that was a mistake.

“Yields have been so high, I don’t know if I should have done that,” he says.

This year, he had 800 acres of full-season soybeans, 550 acres of soybeans double-cropped behind wheat, 350 acres of cotton and 700 acres of corn. He’s yet to decide on next year’s crop mix.

“I have to look at net income per acre,” he says. “This year, we were lucky enough to have high-yielding crops, and I realized I don’t have enough storage. That had never been a real worry before this year.

“So, will this be the norm as we go forward? I’ve been around long enough that I would say no.”

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