Simple steps solidify soybean yields

Know your soils. Keep soil fertility up, and maintain soil pH in the proper range. Pick varieties that perform well in your area, and follow a weed-control program that works. Then hope the weather cooperates. If so, the result should be respectable soybean yields.

Key Points

• Hit the bullseye on the pH target for soybeans.

• The 2009 season was an exception to early planting rule.

• Consider seeding rates, choice of seed treatments carefully.

Mike Mouzin and his father, Joe, of Vincennes, Ind., follow that recipe. It paid off in ’09 with respectable yields, especially considering their soils are primarily sandy, droughty and gently rolling to steep.

One thing they noticed in 2009 was that their varieties were flexible. “Where they weren’t crowded, it wasn’t unusual to find a plant with 150 pods,” Mike says. “In fact, we found one with 300 pods!”

Since their soils are light, the Mouzins strive to keep pH levels in the preferred range. For soybeans, that’s 6.0 to 6.5 for mineral soils, notes Shaun Casteel, a Purdue University Extension agronomist.

In some areas, pH levels may actually be too high, well above 6.5, Casteel notes. Manganese deficiency becomes possible at very high pH levels. Large deviations either way may lead to micronutrient issues. Since soils are highly variable, check with your local crops consultant or Extension adviser for proper pH target ranges for soybeans in your area.

Key steps

To build a solid foundation for respectable yields, pay attention to the basics, Casteel says.

“We’ve tried adding everything but the kitchen sink, and we don’t get much extra yield response,” says Vince Davis, Casteel’s counterpart at the University of Illinois. “That includes applying fungicides and insecticides during the season.

“We’re trying to break through yield barriers, but so far we haven’t shattered the glass ceiling,” he adds.

Here are six keys to building a solid base before you go after super-high yields.

1. Start with nutrient management. “We’ve been ignoring potassium, and deficiencies are showing up,” Casteel says. “We need to get back to basic soil testing, and then apply enough K for soybeans.”

2. Know soil properties. “Ruts and compacted soils will be issues this spring,” Casteel suspects. If compaction is severe enough, nutrient deficiency signs may appear. Plant roots simply can’t get to the nutrients. Soybeans survive such soils better than corn, but it’s not the setting for high yields.

3. Check yield trials to select varieties. Know your area, specialists advise. If there are nematode or root-rot problems, select resistant or tolerant varieties.

4. Shoot for early planting. That’s late April into early May in Davis’ area. Yields typically drop planting in late May or early June. “Later-planted soybeans yielded OK last year, but that was the exception,” Davis says.

5. Pick an adequate seeding rate. But don’t go too high — there’s no need, Davis says. “Deciding on seeding rate is much more important than a decade ago, because seed is more expensive,” he says.

6. Consider seed treatments. There may be a payoff, especially if you’re planting early, Casteel says. “If you’re using seed-coated fungicides, it’s better to have two active ingredients and two modes of action,” he adds.


SEEK BETTER YIELDS: Mike Mouzin and his father, Joe, are impressed by how much their soybean varieties branch and pod at lower populations.

This article published in the February, 2010 edition of MID-SOUTH FARMER.

All rights reserved. Copyright Farm Progress Cos. 2010.