Manure may be a viable alternative to high-priced nitrogen fertilizer, says Jim Gerwing, South Dakota State University (SDSU) soil specialist.
For example, Gerwing says, liquid manure from typical hog finishing barns usually contains 55 lbs nitrogen per 1,000 gallons.
About 50% is inorganic nitrogen — the same as fertilizer nitrogen. The other 50% is in the organic form, a third of which will become available to plants the first year after application. So about 37 of the 55 lbs can directly replace fertilizer when incorporated into the soil.
SDSU nitrogen recommendations call for 110 lbs/acre for a 150-bu corn crop following 35-bu soybeans and having a 2' nitrate soil test of 35 lbs.
At 37 lbs of available nitrogen per 1,000 gallons of hog manure, 3,000 gallons/acre would entirely replace the fertilizer requirement.
The actual nitrogen content of manure varies greatly, depending on the animal species and other factors. So have it tested to determine the proper rate to adequately replace fertilizer and prevent nitrogen losses to the environment, Gerwing recommends.
