3 Reasons Why You Should Consider Topdressing/Sidedressing SO4
#1 Broadens Your Application Timing Window
Weather across the Midwest has gone from snow to spring quickly. If you didn’t get all your sulfur spread last fall or this spring prior to planting, you still have time. SO4 can be spread pre- and post-emergence on corn and soybeans.
The image below illustrates recommended application timing on corn.
#2 Superior Release Pattern
SO4 supplies a balanced initial sulfur release and a steady supply throughout the growing season. AMS is 300x more soluble than SO4 and may release sulfur too quickly leaving the plant deficient later in the growing season.
#3 No Risk of Plant Burn
Some commonly used topdress fertilizers have a high salt index, which is what leads to plant burn – AMS (salt index of 69), and urea (salt index of 75) being prime examples. SO4, which is calcium sulfate or gypsum, has a very low salt index of 8, and therefore, has no risk of burning the plant when topdressed. Click here for more details on salt index.
SO4 is the only sulfur source that you can apply with confidence, knowing it will not burn the plant.