XtendFlex® Soybeans: The Latest on Seeding Rates and Planting Dates

Despite its recent availability to producers, XtendFlex Technology has undergone 2 growing seasons in farmer-managed trials and is currently its first year of commercial availability.

The objective of this study was to determine the effect of planting date and seeding rate on three XtendFlex® soybeans products in response to different agronomic practices and weather conditions.​

• The trial was arranged as a randomized split-plot design with planting date as the whole plot, seeding rate as a sub-plot and soybean product as the sub-sub-plot.
• Planting dates:
• 4/5/2021, 4/19/2021, 5/1/2021, 6/7/2021 and 6/21/21

• Seeding rates:
• 40,000, 80,000, 120,000, 160,000, 200,000 and 240,000

• Soybean products:
• 2.5 maturity group (MG) XtendFlex soybeans product
• 2.7 MG XtendFlex soybeans product
• 2.9 MG XtendFlex soybeans product

• Soybeans were irrigated throughout the growing season.
• 60 pounds of phosphorus (P) per acre, 25-pounds of sulfur per acre, and 0.25 pound of zinc (Zn) per acre were applied through strip-tillage application prior to planting.
• Weeds were controlled uniformly across the study. 
• Harvest dates:
• 9/27/2021, 9/28/2021, 9/29/2021, 10/10/2021 and 10/16/2021

• The highest soybean yields were consistently observed with early planting dates (especially in April and May) (Figure 1).
• The longer MG products (2.7 and 2.9 MG) had higher yields on April 5 and April 19 planting dates compared to the shorter MG soybean product (2.5 MG) (Figure 1).
• There was no difference in yield between the 2.7 and 2.9 MG products regardless of planting date (Figure 1).
• The June 21 planting date had a negative impact on yield on all soybean products (Figure 1).

• Soybean seeded at 40,000 seeds per acre had the lowest yields across all soybean products (Figure 2).
• The 2.5 MG soybean product had similar yields within the range of 80,000 to 240,000 seeds per acre (Figure 2).
• The 2.7 MG soybean product’s average yield increased steadily within the 80,000 to 200,000 seeds per acre range and then declined significantly at the higher seeding rate of 240,000 seeds per acre (Figure 2).
• No difference in yield was observed from 80,000 to 200,000 seeds per acre for the 2.9 MG soybean product. The highest average yield was obtained with the 240,000 seeds per acre rate (Figure 2).

• Plots planted at the earlier planting dates had higher yields across all soybean products, especially in the 2.7 MG and 2.9 MG.
• Late planting (June 21) had a negative impact on yield regardless of soybean MG.
• Depending on the soybean product, irrigated XtendFlex soybeans planted in the range of 160,000 to 240,000 seeds per acre helped maximize yield potential.​

• This trial was a split-plot design with planting date as the whole plot, seeding rate as the sub-plot and soybean product as the sub-sub-plot.
• Planting dates:
• May 20, 2020
• June 12, 2020
• Seeding rates:
• 40,000 seeds per acre
• 80,000 seeds per acre
• 120,000 seeds per acre
• 160,000 seeds per acre
• 200,000 seeds per acre
• 240,000 seeds per acre
• Soybean products by maturity group (MG):
• 2.3
• 2.5
• 2.7
• Trial was sprinkler irrigated.
• Nutrient application included 27.5 pounds of nitrogen per acre, 15 pounds of sulfur per acre and 70 pounds of phosphorus per acre, all strip-till applied prior to planting.
• Weeds were controlled as needed and no additional fungicides or insecticides were used.
• The May 20 planting date was harvested on October 2, and the June 12 planting date was harvested on October 9. Total weight, test weight and moisture content were collected to calculate yield per acre.