Battle for the Belt: Season 3, Episode 10: Adjustments for Late-Planted Soybean

Season 3, Episode 10 of Battle for the Belt is now available:

In Episode 10, we are with Dr. Laura Lindsey, the Ohio State Extension Soybean Specialist, discussing recommendations for late-planted soybeans.

Planting season has been difficult across Ohio due to frequent rainfall, leading to delayed planting for both corn and soybean. As of May 25^th, 52% of the state’s soybeans were planted; many producers throughout the state are now put into the position of planting outside the optimal timeframe.

When soybean planting is delayed, there are a few agronomic practices that should be changed to help mitigate yield losses. Planting date is the management factor that most strongly influences yield, but that cannot always be controlled. However, there are management factors that a producer can adjust to optimize yield in a late planting situation.

The management practices that can be altered with delayed plantings are:

1. Row width
2. Seeding rate
3. Relative maturity

The row width for soybeans planted in June should be no more than 15 inches, if possible. (There may be equipment limitations.) Figure 1 demonstrates that with May planting dates, 7.5- and 15-inch rows have statistically similar yields, but 30-inch rows have significantly lower yields. As soybeans are planted later, narrow row width becomes more important.

If you are planting soybeans in the first half of June, appropriate seeding rates would be between 150,000 and 175,000 seeds per acre. With a goal of a final stand between 130,000 and 150,000 plants per acre. In the last half of June seeding rates should be adjusted even higher to between 200,000 to 250,000 seeds per acre. As planting is delayed seeding rates should be increased to compensate, at least partially, for the shorter season.

Lastly, relative maturity should be adjusted with late plantings. The maturity group that should be chosen in a late planting situation is the longest relative maturity possible that will not be killed by frost in the fall. Choosing a later maturing variety allows the plant to maximize biomass accumulation, increasing the number of nodes where pods can form, before vegetative growth slows down after reproduction begins. Consult Table 1 to choose the most productive maturity group for your region and planting date window.

Field Crop Progress Updates

Last week, two locations were able to add another planting date! At the beginning of the week, the Western location was able to plant before more rain came in, while Northwest Ohio did not receive rain and could plant later in the week (Table 2). Soil conditions were favorable for planting.

The Western location has been progressing quickly over the last two weeks. This location has accumulated the most growing degree days since planting and has now surpassed our Northwest and Wooster locations in heat units (Table 3). The first planting date of corn is at V5 (4/18), and the second planting at V1 (5/12). Sidedress applications to planting date one will be applied soon, as this is the time when plant nitrogen uptake ramps up (V6 stage). The first planting date (4/18) of soybean is at V2, with the second (5/12) at VC.

At the Wooster location, the first planting date (3/27) is at V4 and has had nitrogen applied to the first planting date. Planting dates two (4/18) and three (5/12) were at V3 and V1. For soybean, the growth stages for the first, second, and third planting dates are as follows: V2, V1, VE.

The Northwest location is the furthest behind in the growth stage, while this location has a little more GGDs than the Wooster location, the fields at Northwest are no-till, which takes more time to warm up. Therefore, growth at this location is stagnant with marginal change from last week. Planting date one for corn (3/27) is at V4, with planting date two (4/16) and three (5/12) at V3 and V1. The soybeans are still overall at V1 for the first two planting dates and VE for planting date three (Figure 2).

If you would like to learn more, check out our research updates through C.O.R.N. article updates and YouTube Videos this growing season! You can find the full video playlist of Battle for the Belt on the Ohio State Agronomy YouTube channel.