Variable-rate populations maximize potential
The momentum behind variable-rate populations has never been greater. As farmers seize the opportunity to efficiently position plant populations for maximum yield, the industry is in lock step, offering multiple packages and platforms. The connectivity between data-driven decisions and in-field capabilities is only growing with programs such as Monsanto FieldScripts, Pioneer Field360 and the Winfield R7 tool.
When a field is planted to a uniform population, the farmer is settling for the happy medium, explains Farm Journal Associate Field Agronomist Missy Bauer. If they increase or decrease populations, they’ll see a bell curve showing some areas would like a higher or lower population.
"By using what we know about our management zones, farmers can prescribe planter populations for maximum yields with more confidence," Bauer says. "This is no different than manually lowering populations on the sand hills, for example. When we use prescriptions overlaid with management zones, it’s much more precise."
When mapping management zones, the same factors are taken into consideration to help guide variable-rate population decisions.
"To start, farmers should factor in their soils, yield history and productivity of the zone," Bauer says. "Is it a high-, medium- or low-yielding zone? What’s your soil data, cation exchange capacity, organic matter and water-holding capacity? The overall philosophy is to enable farmers to increase populations where there is higher water-holding capacity and decrease population where there’s lower capacity."
There are two ways to gain yields using variable-rate hybrids: Maximizing the good ground and reducing population in poor soils. Variable-rate population can maximize a soil’s water-holding capacity—lower populations on lighter soils and higher populations on heavier soils.
For some farmers, the end goal of adopting zone management is variable-rate population. Like training for the big game, 90% of your preparation is done before game day.
"With today’s technology and machinery, variable-rate populations by management zone have never been easier to execute," says Jack Hardwick, regional agronomist with AgriGold Hybrids in Missouri and Illinois. "In fact, it’s setting up your management zones and layering data that requires most of the work and time."
Hardwick advocates that farmers seek out advice and help from a local team of experts, whether that be the dealer who sold the desktop software, an ag retailer, a consultant or your seed rep.
"For example, when you write your population prescription map with your seedsman, you’re drawing on their expertise, as well. Together, you can really bring out the potential of a field," he adds. "It’s not an easy task to bring all of the pieces together. Farmers shouldn’t hesitate to ask for help with file transfer from their desktop to the tractor cab. File compatibility can cause a lot of frustration, and it’s better to manage it on the front end."
The first step in variable-rate populations is working with a seed representative to select the right hybrid.
"First, I have the farmer tell me all they can about the history of the field. Knowing things like yield environment and soil types help us then walk through the hybrid capabilities of stress tolerance, ear style and drainage tolerance," Hardwick says. "That is what will increase our success when varying the population."
Know your hybrids. Since variable hybrid systems aren’t commercially available yet, farmers should select a hybrid that will perform best across a majority of their management zones.
Without proper hybrid selection, farmers might be surprised by how their variable-rate populations perform in the field.
- March 2014