Soybean South

 - Southern Specialists -

Consider Burndown Tank Mixes

Dr. Amanda Thompson, Tennessee

Tennessee harvested 1.1 million acres of soybeans in 2005, down 80,000 acres from 2004. The state average yield was 38 bushels per acre down from the state average of 41 bushels per acre in 2004.

Last year the big question for farmers was whether to spray or not with the threat of rust possibly coming to Tennessee. However, farmers were monitoring their fields and managing them better as far as fungicide sprays. We estimate that fungicide sprays went out on 30 to 40 percent of the acres, but some of the applications were to manage other types of foliar diseases.

Although planting intentions aren’t in yet, we anticipate that soybean acres will go up statewide. Part of what is driving that is high nitrogen costs in corn, whereas soybeans do not have a nitrogen requirement.

As far as variety selection, farmers are mixing their maturity groups. We have increased our acres of Group III and Group IV soybeans in the last two years and are planting fewer Group Vs. In some counties, it’s 60 to 70 percent Groups IVs, some Group IIIs and the rest Group Vs.

Another item on Tennessee farmers’ pre-season checklist is burndown. In west Tennessee, we have one glyphosate resistant weed - marestail. Farmers know that in their burndown program they have to include something in the tank mix, such as a dicamba product or 2,4-D to help control that weed. Some farmers have used Valor – a product that the weeds take up from the soil – in their burndown tank mix to give them some residual control of the glyphosate resistant horseweed.

Make the burndown application two to three weeks before planting to make sure you get a good weed kill, including the resistant weeds that are out there so you’ll have a clean field at planting.

The good news is that there was no rust found in Tennessee in 2005. We had 30 soybean sentinel plots and 10 spore traps that we scouted every week. We did find rust-like spores in the traps, but we didn’t have any infection in the field. We are advising growers to be aware of updates and be ready to spray if they have to.

To get good spray coverage, use higher volumes of water - 15 to 20 gallons. Keep the boom height above the canopy at the level that the nozzle company recommends and be sure to calibrate your sprayer.

For more information about Tennessee soybean production practices, go to This Web site has a separate rust area and a soybean specific area that contains variety data and other soybean production information.

Yields First, Rust Second

Dr. Jim Dunphy, North Carolina

North Carolina had about 1.5 million soybean acres in 2005 and averaged 28 bushels per acre. If our farmers had to decide today, that acreage would go up. The price of nitrogen and fuel for corn would be the primary motivation for the increase.

Our main challenge last year was dry weather most of the season. The eastern part of the state got too wet for a while, but most of the state was dry. Before the 2006 season starts, farmers need to think about yields first and rust second. I’m in North Carolina, not in a Gulf Coast state. If I were in Louisiana or Alabama, I would change that order.

Increasing yields in North Carolina depends on the individual farmers. A lot of them have already taken care of many of the things they can do. That’s how they survived the 80s and 90s.

Farmers need to see how close they can come to managing a field as if it were the only field they had. We have to make some compromises, but keep trying to move towards what they would do with that single field. What the key is for one grower won’t be the same as it is for the next grower.

We grow Group Vs, VIs, a significant amount of VIIs and a smattering of VIIIs in the process of spreading out work load, weather risks and harvest. About half our beans are double-cropped with wheat and those are planted in June. The full season beans primarily are planted in May.

We have not gone to the early management system that the Mid-South has because we’re dealing with a very different weather pattern. It simply doesn’t offer us the advantages that it does for them.

Burndown is becoming a common practice in our area. Most of the applications go right in front of the planter. We’re getting more no-till all the time, and that’s our alternative to tillage.

Our primary insect pests are cyst nematodes. To help control them, we recommend rotating with crops other than soybeans preferably every other year.

As far as the threat of rust in North Carolina, farmers are aware of it. It obviously can come this far north, but it would not necessarily be a major problem. It warrants some concern, so we educate farmers about the disease and show them how to look for it.

Last October, rust showed up in 18 of our counties, but it was late enough in the season that it was essentially of no economic consequence. Technically, it entered the state but was not a widespread problem.

In 2005, we estimate that about 2 percent of our acreage got sprayed with fungicides.

We get diseases fairly frequently but not necessarily the same disease at the same time. Many of them for one reason or another do not have a tremendous impact on yields as far as we know.