Tips for great soybean stands
March 30, 2023 | Kriss Nelson
In 2022, some Iowa farmers achieved less-than-ideal stands in their soybean production.
These lower-than-optimal stands reduced overall yield potential and allowed sunlight for late-season weeds to thrive.
“However, while poor weather can reduce soybean stand establishment, there are management practices that improve the likelihood of achieving optimum stands, even in cold and wet weather,” says Scott Nelson, Iowa Soybean Association’s (ISA) research agronomist.
The optimum planting depth for soybeans in Iowa is 1.5 inches.
“This is much deeper than many common planter settings, but planting at this depth provides even emergence as it assures the seed is placed into moisture,” says Nelson.
In no-till or following cover crops, this is especially important.
“Last year, at many sites, we observed large gaps in no-till soybean stands where we placed the soybean seed just below the residue, and it never received sufficient soil moisture for germination,” he says. “Also, planting deeper can help prevent crop injury from some soil-applied herbicides.”
Optimize seeding rates
In a two-year study at a single site, ISA research observed significant increases in profitability of $25 per acre for farmers using variable rate seeding.
In these trials, the lowest seeding rate was 60,000 seeds per acre. This low seeding rate is risky because if any weather or management event reduced stands occurred, seeding rates would not be optimal for yield.
ISA’s general guideline for soybean seeding rates is to target sufficient seed to realize a final stand of 100,000 plants per acre.
“Many farmers are experiencing success at lower final stands than 100,000, but we are unclear on the yield stability and weed control pitfalls for these lower seeding rates,” says Nelson. “ISA’s Research Center for Farming Innovation has a large effort in 2023 better to understand the stability of these lower seeding rates.”
Avoid crop injury from soil-applied herbicides
Sometimes crop protection chemicals can cause early stunting or stand loss in soybeans.
In most cases, this early season crop injury is cosmetic and does not affect final yield.
“If this cosmetic injury is a concern for you, something you can do is to apply soil-active herbicides a week to ten days ahead of planting,” says Nelson. “This tends to lessen the crop response.”
Another practice you can follow is to work with your seed provider for varieties that are more tolerant of the herbicides you need to use.