Within the region, minimal differences have been observed between April and May planted soybeans, although cooler weather and disease may reduce yields with earlier planting. Another issue uncovered in recent DSB research projects is the effects of Al and Fe uptake on reducing early planted soybean yields. One way to reduce the effects of these metals is maintaining a higher soil pH, reducing the solubility of Al and Fe. By increasing soil pH, soybean producers may find that earlier planting on our coastal soils can take advantage of a longer pre-solstice growing season and obtain greater yields.

Alternatively, higher pH may reduce the availability of other metal micronutrients, including Mn, Zn and Cu. It may also give rise to greater edge site cation exchange capacity, allowing for greater leaching of B and SO4 from the soil surface. Rather than having a net sum reduce the effectiveness of liming, we must determine the liming effects on all nutrients taken up in these soils.

1) Lime soils at five rates to observe soybean growth and yield

2) Plant soybeans at two different timings within the lime plots to observe Al uptake

3) Compare the effects of lime and planting timing on yield

Using a regional farmer field, we will establish 10 by 30-foot plots to receive lime treatments as a randomized complete block design (RCBD). There will be five lime rates (0, 0.25, 0.5, 0.75, and 1.0 tons acre-1), two planting timings (April and late May), and three replications for a total of thirty combined plots. Lime treatments will be hand applied in the spring prior to soybean planting. Soil samples will be taken prior to lime application to establish each plots baseline. Soybean tissue samples will be taken at V3 and R1 to establish nutrient uptake over the season. All samples will be submitted to the UD soil testing lab for analyses. Yield will be collected at the end of the growing season using a plot combine. Tissue nutrient content will be correlated to yield and initial soil nutrient levels. Using SAS statistical software, we will compared the plot data as a factorial RCBD to determine treatment effects. Results will be reported to the board as well as at regional extension meetings.

Updated July 28, 2023:
Plots were laid out on a farmer cooperator site near Laurel, DE in the spring of 2023. Lime applications were made on the appropriate spots and then turbo tilled to enhance incorporation. Following this soybeans were planted in April 2023 and monitored through drone imagery and scouting. As this was the earliest planted field in the region, deer damage and feeding was extensive. The "early" planted plots were therefore replanted in late May and the "late" planted plots were pushed back into June. Deer repellent applications have been made to reduce damage and encourage feeding in the nearby soybean fields. Drone imagery has been collected as soybeans have emerged from all plots and tissue sampling has been made at the V3 stage for all treatments.