“Battle for the Belt”, soybean results

By Dusty Sonnenberg, CCA, Field Leader, a project of the Ohio Soybean Council and Soybean Check-off

In the “Battle for the Belt, corn vs. soybean?” the primary question being asked is which crop should be planted first to get the greatest yield benefit. “We can also look at the other side of the question, which crop has the smallest yield penalty for delayed planting,” said Dr. Laura Lindsey, OSU Extension Soybean and Small Grains Specialist. “Can we adjust our management practices to mitigate losses due to late planting? We don’t want to plant late, but sometimes weather conditions in Ohio dictate when we plant, which can be later than we like to see.” 

Delayed planting incorporates considerations beyond the weather. “We need to look at interactions with insects, diseases, weeds, and many other factors. When you alter your planting date, you also alter the problems you may encounter in the growing season,” said Lindsey. “The planting date for both corn and soybeans is extremely important. On average in corn, we have seen a 1.75 bushel/acre/day loss if you plant after the end of April. In soybeans, we have measured about a ½ bushel/acre/day loss if you plant after the end of April. In some years the loss is more and some less depending on the year.”

Ohio soils and weather poses some unique challenges. “The spring planting window can be very narrow. This can force farmers to plant earlier or later than when they would ideally like. The planting window continues to get smaller with fewer days each spring to conduct field work. According to Kansas State University, between April 17th and May 15th in Ohio there are an average of 15 suitable field workdays,” said Lindsey. “That means suitable for any field activities, not just planting.”

“Planting date is the primary focus of this study,” said Dr. Osler Ortez, Assistant Professor, Corn and Emerging Crops. “The study is being conducted at three locations across the state with five planting windows. Those locations include Wooster at OSU/OARDC (Wayne County), the OSU/OARDC Northwest Research Station in Custar (Wood County), and the Western Research Station in South Charleston (Clark County). The planting windows include Late March-Early April, Mid-Late April, Early to Mid-May, Late May–Early June, Mid-Late June.” 

Crop Insurance also becomes a factor to consider in early planting decisions. “Being knowledgeable of your specific crop insurance recommendations and deadlines for the earliest planting dates and latest planting dates should be factored into your decision making,” said Ortez. “On top of the planting dates, we looked at two other factors. For corn, the hybrid relative maturity dates were considered. We looked at 4 different maturities. Later plantings looked at a shorter maturity hybrid and for early planting we looked at a longer maturity hybrid. For soybean the relative maturity and varieties were considered when looking at seeding rates and adjusting accordingly with higher seeding rates for later planting dates.”

For the soybean plots, there were two that performed similarly in 2023. “The Northwest and Western locations had a planting date effect, but no seeding rate effect,” said Lindsey. “Regardless if we planted 100,000 seeds per acre or 210,000 seeds per acre, the soybean yield was statistically the same. This tells us when you plant early to plant your normal target rate. In Wooster there was a planting date by seeding rate interaction. That means that based on your planting date, you should adjust your seeding rate. What we saw with the first two planting dates in 2023 is that we needed a higher seeding rate. On April 14th and 27th we noticed a definite increase in yield as we increased the seeding rate. For the more normal seeding dates, the yields were statistically the same regardless of the seeding rate.”

In the earlier planting dates, the soybean plant populations were very low. “On the April 14th planting date, we needed 210,000 seeds per acre to get a stand of 34,000 plants/acre,” said Lindsey. “The plant population from 210,000 seeds per acre on the April 27th planting date ranged from 22,000 up to 50,000 plants per acre.”

“Interestingly, 34,000 plants per acre is a very low stand, and usually would warrant a replant situation. In this case it yielded 45 bushels per acre,” said Lindsey. “This compared to the normal planting date stand which yielded in the 60’s. Research shows that the replant threshold is 50,000 plants per acre. This year in a plot that had 68,000 plants per acre, the yield was statistically the same as those with a plant stand of over 100,000 plants per acre.”

“In the later planting dates, the stands were good. What is interesting to me is that looking at the May 30 and June 21st planting dates, the plant stands were higher, but the yields were lower,” said Lindsey. “Having an earlier planting date is more important than having a perfect stand of 120,000 plants per acre. If you fall in the 75,000-100,000 plants per acre with a good planting date, those soybean plants can really compensate and maximize yield.”

In general, for what was observed in Northwest and Western Ohio, it is okay to plant early (as soon as the crop insurance date allows) if the soil conditions are right. The crop insurance date for the location in Northwest Ohio is April 15th and the date at the Western Ohio location is April 10th. In terms of the seeding rate, there wasn’t much effect. “When planting early in Northwest and Western Ohio, you may be able to go as low as 100,000 seeds per acre planting early, but it is risky,” said Lindsey.  A normal seeding rate should not be a problem when planting early. In Northeast Ohio more caution is advised if planting early. “From one year of data in this study and two years of data in a prior study we had much lower plant populations and lower yields,” said Lindsey. “It tends to be cooler than our other locations.”

Soybean growth stage development across the locations was also observed in the study. “When we plant early, we tend to have a longer vegetative stage. There is more plant growth and more nodes where pods can go,” said Lindsey. “The flowering stages of R1 and R2 are shifted later, but R3 and R4 are about the same length of time regardless of when you plant, just shifted later. The R5 and R6 growth stages tend to be elongated when you plant earlier. R5 and R6 are critical times to maximize yields. Longer grain fill periods with adequate moisture tend to help maximize the yields.”

The Battle for the Belt will be having a series of winter meetings in March. Presentations will touch on both corn and soybean production and results from the 2023 planting date trials along with other past research and research plans for the future.  

Licking County will host a meeting on March 6th from 8:45-3:00 p.m. https://go.osu.edu/24battleforthebeltlicking

Fayette County will host a meeting on March 8th from 8:45–3:00 p.m. https://go.osu.edu/24battleforthebeltfayette

Hardin County will host a meeting on March 20th from 8:45–1:00 p.m.

Phone (419) 674-2297 to register for the Hardin County Meeting.

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