This time of year, Ken Ferrie fields a lot of agronomic questions from farmers during grower meetings. One common question regarding soybeans that he hears frequently is when to plant early versus late maturity groups. Here’s how Ferrie, Farm Journal Field Agronomist, addressed that question recently at one meeting.
“In what we call a ‘normal’ planting window, we would recommend that you plant your early beans first and your late beans last,” he says. “The main reason for the early beans going out first is they'll quit growing when they reach R5. Flowering is triggered off of night length, and we want enough growth to close the row before this happens. We have to capture all the sunlight, and we want to keep the weeds at bay. Some of our wide-row early beans planted mid-June in 2019 struggled to close the row, leading to weed escapes and loss of yield. We had good responses to narrowing up the bean rows and, in some cases, bumping up populations.”
Because of adverse weather conditions, many farmers pulled out of their early beans this past year and went to mid- or full-season beans. “Farmers responded to the season—they narrowed up their rows and pushed up their populations as the planting season got late,” Ferrie explains.
But what if you want to plant soybeans early? What maturity group do you plant first?
“In our plots, planting any of the maturity groups early seems to improve yields from late- to early-season beans,” Ferrie answers. “I’d say plant your full-season beans first if you're going to plant early—opposite of what we normally do. Remember, the goal is to get the bean to flower pre-solstice, to hold on to those bottom pods.”
Ferrie notes that on the front side of the solstice, the nights get shorter with every passing day. A full-season bean requires a longer night to trigger the flower.
“Our goal would be to get the bean big enough to flower before the nights get too short,” he says. “If the bean doesn't get big enough before the nights get too short, it will flower after the solstice. if we plant all our beans in one week, however, it probably doesn't make much difference,” he adds.
For farmers who want to try some early April planted beans on a few fields, Ferrie recommends going with a full-season bean because time would be on your side for it to get big enough. The opposite is true, too.
“If you plant your early beans first and your late beans last, like we do in a normal planting approach, and your planting window gets stretched out from April to the end of May, your full-season beans may not get big enough to flower pre-solstice because they're the ones you'd be planting at the end of May,” he says. “This is something we typically see in May planting, when growers compare early beans to late beans. If the early beans flower pre-solstice they usually will out-yield the full-season beans.”
When can farmers start early planting of soybeans? Is there a magical date? You can get Ferrie’s answers to those questions—and his corresponding recommendations—in this week’s Boots In The Field podcast here: