Livestock producers across the state are dealing with manure storages that are extremely full. Wet weather last fall, poor winter conditions for manure application, and a wet spring will have many livestock producers needing to apply manure and plant crops at the same time when fields become suitable.
Liquid dairy and swine manure can be applied to both newly planted corn and soybean fields. If applied while the seed is protected by a layer of soil, both corn and soybeans will emerge through surface applied manure.
Corn is more tolerant of manure than soybeans. In research plots and on-farm trials, we have applied swine and dairy manure to corn using a drag hose from just after planting to the V3 stage of growth. The manure did not seem to hamper corn emergence and growth. The only obvious damage to the emerged corn plants was when the tractor wheels crushed them. These plants are always slightly behind the remainder of the field but still produce ears.
Soybeans can be easily killed by swine finishing manure when emerging from the soil or already emerged. We have wiped out double-crop soybean stands using swine finishing manure rates of 5,000 gallons per acre. I have had livestock producers tell me they have applied sow manure and nursery manure to soybeans without a problem. Other livestock producers have said they have reduced soybean yields when manure has been applied to established soybeans. Based on one year of data, we know a drag hose (no manure applied) does not damage soybeans enough to reduce yields at stages V1, V3, and V5.
If you think you will be working with a commercial manure applicator to apply manure to newly planted crops, be sure to contact them well in advance. Commercial applicators I have spoken with are stretched extremely thin with all their regular customers with full manure storage facilities.
Surface applied manure is at risk to runoff caused by pop-up thunderstorms. Be sure to print out rainfall forecasts when starting the manure application and check with your SWCD office about setbacks from ditches and streams.