Plant Full-Season Soybeans by Mid-May to Prevent Yield Loss

(Updated: May 12, 2023, 6:16 a.m.)

Using the right soybean planting date is one of the most important management decisions in soybean production.

We have been generating data since 2019 to help growers make decisions about soybean planting date across production situations (regions, maturity groups, seeding rates, yield environments) in North Carolina. We have conducted this research in diverse production environments (n=15) over the past four years.

We have consistently seen that delaying planting date past mid-May decreases soybean yield in our state (Figure 1). Yield loss per day as planting date is delayed is not constant as time progresses but generally we are losing anywhere from 0.45 to 0.87 bu/A/d by delaying planting past May 20.

Delayed planting impact on soybean yield across NC regions: In general across maturity groups, the yield loss from delayed planting is greater in the Tidewater region than the Coastal Plain or the Piedmont region by about 0.1 bu/A/d.

Delayed planting impact on soybean yield across maturity groups: In general across regions, the yield loss from delayed planting is greater for earlier maturing varieties (MG 3 and 4) than later maturing varieties (MG 5-7) by 0.1-0.2 bu/A/d.

The last USDA -NASS report estimated that only 15% of North Carolina soybeans were planted by May 7, 2023. Based on our wheat acreage estimates (510,000 acres) and our soybean acreage estimates (1,750,000 acres), our double crop soybean acres will be no more than 30% of our total soybean acres (USDA-NASS). So we have a lot of full season soybeans to plant over the next week!

Figure 1. Soybean yield loss as planting date is delayed past mid-May for different NC regions and maturity groups