By Brianna Smith
After several weeks of rain and persistent delays, many Ohio farmers face tough decisions about late planting and replanting. Taylor Dill, Ph.D. student in the Department of Horticulture and Crop Science at The Ohio State University, advised by Laura Lindsey and Osler Ortez, shared timely insight based on her work with the statewide Battle for the Belt research trials.
Dill shared that farmers need to consider their row spacing, seeding rate, and relative maturity when considering late planting.
“So, for late soybean plantings, the later you plant, the higher seeding rate we want to be planting,” Dill said. “Upping the population helps to increase yield. You need more plants physically out in the field, because late planted soybeans do not have the same opportunity for vegetative growth. In our Battle for the Belt fields, we have seen that with late planting dates both vegetative and reproductive growth are accelerated, which means that there is less time for node formation, which leads to less pods per plant.”
Appropriate seeding rates for the first half of June are about 150,000 to 175,000 seeds per acre. For the last half of June, 175,000 to 200,000 seeds per acre is recommended, and in early July, the recommendation is 200,000 to 250,000 seeds per acre. The row spacing for June planting should be no greater than 15 inches.
When it comes to planting corn later in the year, the maturity of the hybrid could impact overall yield success.
“In our plots, we have four corn hybrids ranging from 100-day to 115-day, and we have our five planting dates,” she said. “As we got later in planting, an earlier maturing hybrid usually fared better.”
Dill emphasized that this is especially important in the northern parts of the state.
“In northwest Ohio, it’s very important to consider our growing degree days up there. It is not the same as southern Ohio,” Dill said. “Those later planting dates need the growing degree days to get to the black layer before the first frost. An earlier maturing hybrid is much more likely to have that happen.”
For farmers considering replanting corn, stand counts should be the deciding factor.
“With corn, it’s really by population,” Dill said. “It’s important with corn that we have a certain number of plants by a certain date, as we begin to decrease yield potential as we delay our planting. This is because corn cannot compensate for stand loss like soybeans can.”
She noted that tearing up a field based solely on appearance could backfire.
“If you planted in April and you have a decent stand, your yield potential will still be better than planting and having your full population later in May,” Dill said.
Soybeans follow a different logic.
“Soybeans are all about plant distribution rather than necessarily a certain number of plants per acre,” Dill said. “When considering your initial seeding rate for a crop planted in May, we want to have the goal of at least 100,000 plants per acre as a final stand, especially because you’ll still canopy over.”
However, if uniformity is poor, it may be time to consider a replant.
“If you have spots that you know aren’t going to canopy and you have than 50,000-60,000 evenly distributed plants per acre, you might want to consider replanting or spotting in that field, Soybeans can handle this low of a population because of the plants ability to fill in the space by developing auxiliary branches.” she said.
Timing is also critical when deciding whether to replant. For soybeans, yield loss resulting from delayed planting ranges from 1/4 bushel to more than 1 bushel per acre per day, depending on the row width, planting date, and plant type. Corn yields decline approximately 1 to 1.5 bushels per day for planting delayed beyond the first week of May.
Given these steep yield penalties, replanting should never be automatic.
“It’s really important to go do stand counts and your actual population through your field,” Dill said. “Whether you’re going to kill it or whether you’re going to try to spot replant, make sure that you go out and do as many stand counts as will be representative of your field.”
With yield losses increasing each day after early May, Dill emphasized that replanting should be based on real data, not assumptions. “Sometimes you might be better off with a low population, because of how delayed the planting would be and the potential yield loss associated with late planting,” she said.
