Kinze planter in field

(Photo: Iowa Soybean Association / Joclyn Bushman)

Four planting tips to help achieve maximum yield

March 11, 2024 | Kriss Nelson

A successful harvest begins at planting

Seed selection has been made. Now is the time to do everything possible to give that seed the best possible start this spring.

1. Planter setup

“For the first day of planting, patience is the name of the game,” says Iowa Soybean Association (ISA) District 2 Director Sam Showalter. “It includes dozens of trips in and out of the cab and a lot of time on your hands and knees digging up plants to check depth, auto-shutoff settings, populations and spacing.”

Every pre-plant checklist for the Showalter farm near Hampton begins after planting the previous year’s crop.

“We note any lingering issues that need addressing in the offseason; we give the planter a bath and a grease before we put it in storage for the rest of summer/winter,” says Showalter.

Every winter, Showalter pulls the planter out of storage and revisits last spring’s notes. He’ll tackle as much of the routine maintenance as he can.

“When it leaves the shop in the winter, our goal is that it’s ready to head to the field,” he says. “Once we get to actual planting season, the checklist is manageable.”

2. Planting conditions

Optimal planting conditions call for soil temperatures to be 50 degrees at the four-inch depth and trending warmer.

“If it’s early and the soil temp is still below that 50-degree mark and it’s dry, and there will not be rain for the next two weeks, I would probably hold off on planting,” says Drew Clemmensen, ISA Research Agronomist. “If there’s rain forecasted within the next week, especially in drought conditions, I feel more confident planting that seed.”

What happens to the seed if it is planted in cold soil and receives cold rain?

“When the seed takes on water and initiates mesocotyl growth and suddenly takes on cold water, the plant cells become more ridged and can burst, which can cause erratic growth underground,” says Clemmensen.

Sometimes, the seed can correct itself and emerge, but that isn’t always the case.

“That plant has a challenge of getting out of the ground. If it gets far enough behind, it essentially becomes a weed and doesn’t produce as it should,” says Clemmensen. “There aren’t guidelines that fully explain what happens under certain temperatures or rainfall; sometimes it’s based on luck.”

3. Planting depths

An even, timely emergence starts with a uniform planting depth with good seed-to-soil contact.

Planting soybeans deeper than the 1½ inch depth can put the seed in more uniform soil temperatures.

“It gives us an opportunity for all the seeds to germinate and emerge uniformly,” Clemmensen says. “The topsoil also acts as a buffer to protect the seed from some of those spring temperature influxes.

For corn, Clemmensen says literature advises a planting depth of 1½-1¾ inches, but he suggests planting deeper, at two inches.

“A deeper planting depth allows brace roots to form and be more productive than at a shallower seeding depth,” he says. “Err on the side of planting deeper; I have even seen better stands at a four-inch planting depth versus some of those planted shallower.”

Get out of the tractor and check what is happening behind you.

“We all get into that ‘I have to keep this planter running’ mentality. We set the planter, and we go. The monitor tells you the spacing and depth are right, but get out and physically check as you go across the field,” he says. “Soil types change, field conditions change, and that can affect seeding placement.”

4. Seeding rates

General recommendations for soybean seeding rates are planting 120,000 to 140,000 seeds per acre, aiming for a final plant stand of 100,000 to 120,000 per acre.

Preliminary results from 2023 seeding rate trials show a 2-2.5 bushel to the acre yield boost from planting 170,000 or 140,000 seeds per bushel versus 80,000 seeds per bushel.

Results in trials comparing 110,000 seeds per acre to 170,000 seeds per acre and 110,000 seeds per acre to 140,000 seeds per acre show little difference in yield.

Variable-rate seeding is another option as farmers head to the fields. This technology can adjust the seeding rate to accommodate field conditions. ISA’s Soybean Variable Rate Planting Simulator Tool, located on the ISA website, helps farmers understand how adjusting seeding rates could yield profitable outcomes.

ISA Spatial Data Analyst Josh McDanel says the tool uses three years of historical soybean yields, seed costs and expected yield responses to simulate different variable planting rate scenarios to maximize return and minimize cost.

“We are going to continue these trials in 2024 and we hope to get enough data from these to implement what we learn from them into the soybean variable rate seeding simulator,” McDanel says.

A pre-plant checklist

Replace worn bearings and bushings

Determine wear in disk openers and gauge wheels to minimize variability

Gauge wheels

“We are just looking for worn-out tires,” says Showalter. “The impact of no-tilling soybeans is the leftover stover from the previous corn crop is harder on tires. Eventually, we’ll see cracks; stalks will get caught inside, catch different wires or hoses, and just cause problems.”

Disk openers

Disk openers are measured and checked for consistency for every row. “These are what sets the depth of seeding when we are planting,” says Showalter. “Over time, these disks wear and get smaller, and there is a threshold where they need replaced.”

Bulk planters

Drew Clemmensen, ISA research agronomist, says understanding how your bulk planter can change from fully loaded to almost empty and what adjustments need to be made. Monitoring equipment should make these adjustments — but you do not know for sure unless you get out and check.

Level the planter

The planter should be parallel to the ground. “All the benefits of precision attachments go out the window if the toolbar is not level,” says Clemmensen. “In my opinion, planting is the most important task in the entire crop year,” says Showalter. “If the planter is not functioning properly, in adequate conditions, we are not doing our part to have a successful crop."