Mike Reicherts applied 141 lbs of purchased nitrogen and compared that to corn sidedressed with the same amount of manure nitrogen. Only about half the nitrogen in unincorporated liquid manure is available to the crop. Despite this, the sidedressed corn yielded at least as well as corn with purchased N. The manure system came out ahead financially as well, if only spreading costs were charged against the crop.
Dick Svoboda also compared manure and purchased nitrogen. The manured corn yielded significantly better, even though there was less available N applied with the manure. Leaf tissue tests from the trial show significantly higher potassium with the manure. In the past dry years some early season potassium deficiency symptoms have appeared on the farm. Dick has been helped in the trial by Alan Britten, Extension coordinator of the Benton County manure project.