Maximize soybeans in Louisiana

In 2006, soybeans were Louisiana’s most popular commodity with acreage ranging between 800,000 and 1 million. And despite drought and ample disease, the state set a new average yield record of 35 bushels per acre.

At the recent Louisiana Soybean Association annual meeting at the Dean Lee Research Station in Alexandria, La., David Lanclos spoke on how producers can best maintain and maximize soybean production in 2007.

“Louisiana corn acreage has been sinking, no doubt,” said the LSU AgCenter soybean specialist. “We’ve been dropping acreage for the past few years. But in 2007 it appears we’ll pick all those acres back up and add some.

As for wheat, USDA has Louisiana production at about 225,000 acres. “That will factor into the scheme next year in terms of what farmers do with their double-crop acres. Will we plant cotton behind wheat? Will it be soybeans or, in some situations, milo? We’re not suggesting you should plant milo behind wheat — we don’t think it’s a very solid practice.”

Sugarcane acres are expected to remain stable.

Lanclos says rice “could see a 5 percent to 10 percent increase in acreage. However, considering the hit rice acreage took in 2006, it still won’t be a tremendous number of acres.

“We also expect grain sorghum to be back to 200,000 to 250,000 acres.

Maturity groups

Every year Lanclos fields many questions about maturity groups.

“From a pure production standpoint, we have some Group 3s being planted, primarily north from Tensas Parish. That’s exactly where they need to be. We also have some very limited Group 3 data out of the sugarcane region.”

In central Louisiana, the soybean crop is predominantly Group 4s and Group 5s. And in south Louisiana, producers are “mostly limited to Group 4s and Group 5s.”

Cobbled together from statewide Extension demonstration work, the last three years of trend data for Group 4s shows the following: south Louisiana is averaging 36 bushels per acre, central Louisiana’s average is 39 bushels, and north Louisiana is at 52 bushels.

“This shows there’s definitely a place for Group 4s. I’ve been in this job for several years now. Having watched this closely, I believe the maturity group break-line for the state is right here in Alexandria. The (agronomic) dynamics south of Alexandria drastically change.”

The data for Group 5s shows: south Louisiana averaged 40 bushels, central Louisiana averaged 52 bushels, and north Louisiana averaged 58 bushels.

“The take-home message remains the same: the further north, the less the insect and disease pressure. The northern beans are also a bit more intensively managed with irrigation and that translates to higher yields.”

As for the best varieties, Lanclos’ list of 3.8s and 3.9s includes DPL 3861, Dyna-Gro 31J39, Delta Grow 3950, Delta King 3964, and Terral 39RS31.

The best-bet for Group 4s, range from 4.1 to 4.9: Delta Grow 4150, DPL 4546, DeKalb 46-51, Terral 46R15, DPL 4724, Pioneer 94B73, Delta King 4866, Pioneer 94M80, Terral 48R14, Delta King 4967, Dyna-Gro 36M49, MorSoy 4993, Prodigy 4949 and Terral 49R12.

The best Group 5s, listed by maturity: Delta King 5161, Delta King 5366, Delta Grow 5555, Delta King 5567, Terral 55R15 and DPL 5634.

“These are all exceptional varieties. But for the last couple of weeks I’ve been strongly encouraging growers not to go much later than 5.6 to 5.7. That’s because of the late-season issues we’ve had with disease as well as the potential for Asian soybean rust. Planting later varieties is an undue, unnecessary risk.”

The LSU AgCenter won’t recommend any Group 6s for the state in 2007.

“We have only two or three commercial 6s in the state. They just aren’t working, and we need to be pushing the early-maturing beans.”

Core block studies

In late 2004, the LSU AgCenter incorporated a “core block” facet into its Crop Demonstration Program. The purpose was to evaluate soybean, corn and grain sorghum varieties across the wide range of agronomic conditions Louisiana offers. What’s been found in soybeans?

In the Group 3 core block studies last year “we had four varieties in three rotations statewide. The top yielder was Terral 39RS31, followed by DPL3861.

“As for Group 4s, the state locations numbered 11. Delta King 4866 was tops and the following tied for second place: Terral 48R14, Dyna-Gro 36M49, DeKalb 46-51 and DPL 4546.”

Broken down by regions — “when you have 11 or 12 locations statewide the discrepancies between regions begin showing up” — three locations of Group 4s in south Louisiana showed Dyna-Gro 36M49, Terral 48R14 and Delta King 4866 led the way.

“For central Louisiana, the best were Delta King 4967, Terral 49R12 and Delta King 4866. In north Louisiana, the best were DeKalb 46-51, Delta King 4967, DPL 4546 and Pioneer 94B73.”

Group 5s were studied across 14 locations: seven in south Louisiana, six in the central region and one in the north.

“Terral 55R15 led the pack at about 57.5 bushels. That was followed by Delta Grow 5555, DPL 5634, Delta King 5161 and Delta King 5567.

“Exceptional beans in south Louisiana were Terral 55R15 and DPL 5634. In central Louisiana it was hard to separate the varieties. In north Louisiana, the best were Delta Grow 5555, Delta King 5567 and Terral 55R15.”

Cultural practices

While speaking on cultural practices, Lanclos applauded Trey Koger’s work in Mississippi. Koger, a USDA soybean agronomist in Stoneville, Miss., has done “research that is extremely interesting.”

“We’ve had a lot of questions in soybeans, milo and corn on twin-row systems. I’ve never been a big proponent of twin-rows, but Mississippi has been working with twin-row soybeans and corn for several years.

“Koger has studied a 10-inch system, a 20-inch system, a twin-row and 40-inch row spacing. He found the narrow rows have a 9 percent yield increase over wide rows.

Lanclos said a twin-row system makes good beans better. But it won’t make poor beans a lot better.

“If you have 35-bushel beans, the twin-row system could bring you to 43 bushels. It won’t take 35 bushels beans to 70 bushels.”

What about seeding rate response?

“Many companies pushing the twin-row planter claim you need to increase the plant population to maximize yield. Koger compared 130,000 plants per acre to 155,000 plants per acre. The 155,000 plants did have a bit of a yield response, with the exception of the 40-inch row, where the lesser population actually did better.”

The message remains the same. “Regardless of the plant population, the 10-inch, 20-inch, and twin-row systems beat the wide row.”

Drainage, beds

Behind variety selection, Lanclos said, drainage is the most overlooked cultural practice in Louisiana.

“Soybeans don’t like wet feet. If you can keep them dry and keep them actively growing, you’ll increase yield. If they stay waterlogged and struggle, the bottom line will be hurt.”

Another message: “When you plant extremely early or extremely late, do so in narrow rows.”

There have also been a lot of questions recently on raised beds versus flat.

“I’m not saying those planting flat won’t make a good crop. But, for the last couple of years, those planting on a bed system are increasing yields.”

Again, Lanclos pointed to Koger’s work.

“He did a 40-inch hip bed and got a return of about 7 bushels per acre — about $38 per acre extra profit. When he went to an 80-inch bed, the profit dropped to $27.”

Koger believes the reason is 80-inch beds often produce a slight depression in the middle.

“So, from 40 inches all the way out to 70 inches is probably where you need to be. Going all the way to 80 inches is a bit too large and it will be hard to get uniform thickness. We need more research on this, but we’re going in the right direction with beds.”

Lanclos believes that in the next five to 10 years, “most Mid-South soybean production will be on beds. The yields are there and most production teams are moving towards them. Two southwest Louisiana farmers called me this week saying they’re buying bedding equipment for their beans.”

Plant populations

Where can producers save money in soybean production?

“Plant population is one of the first things to come to mind because, in many situations, we’re planting too thickly.”

With Group 3s in early April, producers need 120,000 to 140,000 plants per acre. With Group 4s in early April, “it’s hard to separate” between 70,000 and 155,000 plants. For Group 5s, producers need to be between 95,000 and 120,000 plants.

“In mid-April, the message with Group 3s remains very clear: higher plant populations — above 120,000 — increase yields. With 4s, you can go as low as 95,000 and still maximize yields. For Group 5s, you’ll maximize yields with 80,000 to 100,000 plants per acre.”

In mid-May, Groups 3s need higher plant populations to get higher yields.

“With those higher yields, you’ll justify the cost of adding seeds to the ground. With Group 4s, yields are maximized at 90,000 to 100,000 plants. As for Group 5s, it’s hard to separate yields with populations at 70,000 and 155,000.”

When is the best time to plant?

“You need to wait until the first of April to plant a Group 4. In years to come, that may change. But there are many other issues we’ll have to figure out before we recommend planting a Group 4 earlier than that.”

When ASR hit two years ago, Lanclos was concerned with the best date to plant Group 5s. At that time, Group 5s were typically planted at the end of May. Since then, producers moved the planting back to mid-May and then some began planting at the end of April.

“We started looking at (Group 5 planting dates) with 10 varieties in the core block. Those were planted April 4, May 4, May 17 and June 2.”

Before discussing the results, Lanclos pleaded with farmers not to plant on April 4. “This was just an interesting study that needs to be pursued much more.”

The LSU recommendation for the earliest Group 5 planting date is April 25. This makes sense because, historically, Group 5s are determinates.

“They’re very photo-period sensitive. You could end up with a bean that’s 7 inches tall.”

Regardless, despite Lanclos’ warnings, producers will no doubt be impressed with the 74-bushel yield on the test’s first date of planting.

“It was unbelievable and if we’d eliminated a bit more disease pressure, the yield would’ve been around 90 bushels. The yields decreased with subsequent planting dates. On the last planting date we had a hard time just getting the beans up.”

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