Nitrogen Sources and Methods of Application for No-Tillage Corn Production
1982
Touchton, J. T. | Hargrove, W. L.
The efficiency of properly applied urea N fertilizers is generally equal to the efficiency of ammonium nitrate. Proper applications, however, most often include incorporation soon after application. In no-tillage systems where cultivation is not a common practice, these fertilizers are often applied as surface sidedress applications and are sometimes used as carriers for contact herbicides. These field studies which were conducted for 3 years on a Cecil sandy loam soil (Typic hapludult) were designed to compare the efficiency of prilled urea, urea-ammonium nitrate solution (UAN), and prilled ammonium nitrate (AN) as affected by methods of application in no-tillage corn (Zea mays L.) production. Treatments included shallow incorporated and unincorporated band applications of all N sources plus a broadcast spray application of UAN. Nitrogen rates were 90, 180, and 270 kg/ha. The results for corn grain yield showed that, in comparing the three N sources, the order of efficiency is generally urea < UAN solution ≤ ammonium nitrate. However, in comparing the three methods of application (surface band, incorporated band, and surface broadcast spray) for the UAN solution, little difference was observed between the surface or incorporated band applications. The surface broadcast spray treatment, on the other hand, resulted in considerably less grain yield and N uptake as judged from the ear leaf N concentrations. These results indicate that, at least for the conditions of this study, urea is not an efficient N source for no-tillage production systems and is especially inefficient when applied in solution as a broadcast spray.
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