To ensure soybean recommendations are fresh and up-to-date, Trey Koger and his Mississippi Extension research colleagues have done much fieldwork and studying over the last few years.
“We are constantly evaluating new technologies as well as revisiting existing technologies to make sure they are providing economical returns under our current soybean production systems,” said Koger, Mississippi Extension soybean specialist, who spoke at the National Conservation Systems Cotton and Rice Conference in Marksville, La. “Many of these recommended inputs are standard in all SMART fields (known as verification fields in other states) as well as included in enterprise budgets because they provide consistent positive net returns.”
Some of the things Mid-South soybean growers should consider:
Variety selection: Making the correct selection for factors such as soil type, irrigated versus dryland systems, and planting date is paramount. “A lot of other things I'll mention cost money whether through equipment, seed treatments, and/or pesticide inputs require an input cost in order to see an economic return, or high yield. However, (although the seed isn't free) variety selection does not cost the grower money — it's a free input.
“Growers need to pick a variety in a timely manner in the fall. It's very important to choose the right one for the soil type, planting date and environment.”
Transition of cotton land to soybeans: In recent years, the Mid-South has shifted a lot of cotton soils to soybeans. In Mississippi, “we are growing a lot of soybean on silt loam soils that historically have been growing cotton.”
In 2008, approximately 30 percent of Mississippi's soybean crop was grown on such soils. “That's a major deal.”
Currently, almost all soybean varieties are being developed by private seed companies. Ninety percent of the varieties are for mixed to heavy clay soils.
“That makes sense because, until the last two or three years, that's where the market has been” for the Mid-South region. “But when you take some of those varieties and put them on sandier soils, they have the potential for excessive growth and, in some cases, lodging. Producers should be aware of that possibility when picking the right variety.
“One thing we did with the (MSU) suggested soybean variety list in 2008, was to provide more information (see http://msucares.com/crops/soybeans). For every variety listed, the soil type it's best-suited for is included along with the plant color (is the bean red, grey or tawny?), the growth habit of the variety (a tall bushy variety or a short-statured variety?), and whether or not it is an STS variety. That will allow growers even more information when picking soybeans varieties best suited for their operation.”
Bedding systems: The importance of bedding systems is especially important for flat, deep Delta soils that have been graded for rice and soybean production. “The biggest production issue we deal with in that environment is surface drainage. It's very, very important to provide surface drainage that allows irrigation but also gets water off the field as quickly as possible.
“It's been shown repeatedly that if you're willing to spend the money to put soybeans on an elevated row — whether a 40-inch row or 80-inch bed — yields are consistently increased. That yield increase, of course, depends on the year and weather pattern. With a wetter summer, the grower will likely see bigger yields, larger net returns.
“But on elevated rows, we're seeing yield increases of 5 to 20 bushels per acre consistently.”
Row spacing: What about twin rows versus a single 38-inch or 40-inch row? Koger says research data shows yield increases of anywhere from 7 to 12 percent — across years, varieties, planting dates, maturity groups — of twin-row yields over single-row 38- or 40-inch row yields.
However, the twin-row advantage doesn't hold true against all single-row spacings. A 10- or 20-inch row will yield the same as twin-row beans “if - and this is a big if - surface drainage is provided through some type of elevated bed.”
A lot depends on the type of operation being considered. “For a rice/soybean grower farming heavy clay soils and utilizing a narrow row pattern, the biggest production issue is likely surface drainage not row spacing. That grower would probably be better off spending money on equipment to build elevated beds of some sort.
“A lot of times, we suggest planting soybean on an elevated, wide bed — a 76- or 80-inch bed. That's conducive for most narrow row patterns.
“Flip that around. If I'm a cotton/corn grower with a lot of silt loams and mixed soils, more than likely I've already got the equipment to put up an elevated row — maybe a 38- or 40-inch hipped-up row. I'd probably be better off going the twin-row route because I could plant twin-row bean or twin-row corn and use an offset hitch to plant single-row cotton.”
The “Cadillac, optimum system” is a twin-row pattern up on a 38- or 40-inch row. Using that, the producer gets the best of both worlds: the optimum row spacing and optimal drainage.
Insecticide seed treatments: At $9-per-bushel soybean prices, about 90 percent of the time, insecticide seed treatments provide Mississippi growers with a positive economic return. Mid-South entomologists “have investigated the utility and economic potential of insecticide seed treatments across a lot of environments: many crop rotation scenarios, planting dates, and soil types. And with all those options, the vast majority of the time, the use of an insecticide seed treatment results in an economic return to our soybean growers.
“I don't tell growers, ‘put a treatment on every seed.’ It's a moving target — a lot of times, you can't visually see what that treatment is providing. However, the benefits are seen at the end when the field is harvested.
“It helps with early-season pests — and in Mississippi, we see bigger net returns the earlier we plant. A dry spring may mean a lot of thrips pressure. We believe the treatments are helping with three-cornered alfalfa hoppers and bean leaf beetles, with some underground pests like grape colaspis larvae, some of the white grub worms.”
What Koger does tell growers: if you haven't tried a seed insecticide treatment, try one of the two available on a field. “Call your distributor and have them apply it to the seed for a given field. Try them on your earliest planted field or one that may have some residue that may be harboring insects. Try it on a field where you have historically seen more early insect pressure.”
Seeding rates: Until the 2009 crop Koger wasn't asked much about seeding rates. Roundup Ready seed price increases “have made that discussion necessary. We were dealing with prices around $34 per bag previously. Now, farmers are looking at $45 to $55 per bag.
“That's led to a lot of questions. ‘Am I planting the right number of seed?’”
In recent years, much research has been done on seeding rates. Group 4s and Group 5s need to be at around 100,000 to 110,000 plants per acre — “not seed, but plants. For those groups, a plant population much higher than that hasn't resulted in a yield increase and is actually resulting in us spending more money than needed.
“If you're planting more seed and not seeing a yield bump, that's lost money.”