Soybean varieties perform best when placed in the right environment and soil that they are best adapted to. Seed companies talk about variety placement and farmers practice it as best they can, often based on recommendations from their seed dealers. But how well do farmers really understand how placement works?
I realize it is a challenge to do this right and takes an understanding of both the soil and environment you farm in (something a farmer knows best), as well as the characteristics of individual varieties (something seed dealers know best). Placing varieties is a collaboration between the farmer and seed dealer.
Kelli Bassett, regional agronomist with Pioneer, has been helping growers in Illinois better place their soybean varieties and recommends they focus on four areas including the environment, soil type, cropping history and known soil limitations.
Recognize the Environment: First thing to recognize is whether you are planting in a high- or low-yield environment. Growers know that with corn you place the racehorse variety in the best environments. Same goes for soybeans. Bassett recommends planting offensive varieties in fields with high-yield potential. “In low-yielding environments, growers should plant defensive varieties with a strong disease package to offset disease issues or drought risk in the area.”
She adds that soil type and planting date influence the environment. “A black soil has more water-holding capacity than a timber soil does. A timber soil is lighter, shallower and more prone to drought unless it rains weekly. And planting early increases disease risk and requires more genetic resistance and seed treatments compared to late planting.”
Row spacing impacts the environment and should determine variety characteristics. Bassett suggests that if you farm in 30-inch rows, then select bushy varieties that will close the canopy over the row sooner. If you drill or plant 15-inch rows, plant canopy width and characteristic is not as important since rows will close sooner on their own.
Know Your Soil Type: I always considered the soil the most important element of variety placement. Questions to ask yourself when considering your soil types include:
- Are they well or poorly drained?
- Is the texture predominately sand, silt or clay?
- Is the predominant landscape a heavy boot or clay knob?
- Does the soil originate under prairie or timber?
Bassett recommends selecting varieties for the predominant soil conditions in the field. “For the soil type, focus on height,” says Bassett. “For lighter soils you typically need more height, so select taller varieties. Taller plants mean more nodes, branches and pod-bearing sites. For heavy soils, where soybeans can grow too tall and lodge, consider a more compact plant type for variety selection.”
Recognize Your Cropping History: With lower corn prices, many growers are more interested in growing more acres of soybeans. Bassett points out that in fields that having been in continuous corn for more than five years there is good yield potential and the opportunity to manage for high yields. “There is reduced SCN, less diseases pressure and there can be residual nutrient carryover resulting in greater yield potential.” However she points out that under these environments there is greater risk of lodging, so be prepared.
And in the instances where growers plant continuous soybeans (two or more years in a row), Bassett suggested planting a different variety with a strong defensive package the next year.
Know Your Soil Limitations: Each field has some limitations that need to identified and planned for, either with variety selection or agronomic management. Bassett points out that you need to recognize issues like iron chlorosis, routine drown out spots, past disease issue, SCN hotspots, white mold risk, etc. “Select varieties and management practices that lessen the risk that yield will be reduced.
Agronomist Dr. Daniel Davidson posts blogs on agronomy-related topics. Feel free to contact him at firstname.lastname@example.org.