No-till corn yields comparable to those achievable with chemical nitrogen fertilizer can be produced with liquid dairy manure as the only nitrogen source — if the manure is incorporated at application, according to studies by two Ohio State University researchers.
However, yields from non-incorporated manure applications were significantly lower than those achieved with incorporated manure, say the researchers, extension agents Ernest Oelker Extension and Gary W. Graham.
After 2 years of study on the Myron Wehr farm in Columbiana County, Ohio, the researchers also concluded that equipment and application methods are available to incorporate liquid dairy manure on no-till fields while maintaining adequate residue for no-tilling.
They also found that manure applications did not result in significant compaction, probably due in part to the improved carrying capacity of no-till soils. And there was no significant interaction between the method of application and the season of application on subsequent corn populations. However, they suggest that no-tillers consider increasing seeding rates after spring incorporated manure applications.
In 2002, Oelker and Graham measured the effects of fall and spring manure applications, incorporated and surface-applied, on plant population, soil nitrogen, plant tissue composition and no-till corn yields. An Aerway manure distributor pulled behind a 2,600-gallon Husky tank was used to apply 11,800 gallons of liquid dairy manure per acre.
Extremely dry weather limited yields to an average of 69.4 bushels per acre. Spring incorporated manure plots produced severely reduced plant populations averaging 13,115 plants per acre, compared to an average of 26,924 plants…