Nitrogen Fertilizer Source, and Method and Time of Application Effects on No-till Corn Yields and Nitrogen Uptakes1
- R. H. Fox,
- J. M. Kern and
- W. P. Piekielek2
The increasing use of both no-tillage corn (Zea mays L.) production and ureasontaining fertilizers makes it imperative that we develop management strategies that maximize economic return from applications of these fertilizers to no-till corn. A 3-yr experiment was conducted on a Murrill silt loam (fine-loamy, mixed, mesic Typic Hapludult) to determine the relative efficiencies (yield and N uptake per unit of N applied) of three common N sources [NH4NO3 (AN), urea, and urea-ammonium nitrate solution (UAN)] used on no-till corn. They were applied either as a surface band or as an injected band at or near the time of planting, or as a sidedress 26 to 31 days after plant emergence. Surface-banded AN, injected AN, and injected urea all produced similar no-till corn yields and N uptakes. The apparent NH3 volatilization loss from surface-banded urea was strongly influenced by the number of days after application until a total of 10 mm of rain fell. Apparent losses ranged from less than 50 g kg−1 of applied N with 10 mm of rainfall within 2 to 3 days after application, to over 300 g kg−1 with 5 to 7 days of dry weather after application. Both surface-banded and injected UAN were less efficient than AN or injected urea. Sidedress applications of N resulted in more efficient N fertilizer utilization with all sources, but particularly with urea-containing sources. Shorter rain-free periods after sidedress applications may have contributed to this effect. Surface applications of an experimental fertilizer, 31 urea/urea phosphate, produced greater ear-leaf at silking N concentrations than did surface-banded urea. Amending urea with KCI, or UAN with ammonium thiosulfate, did not result in yields, ear-leaf N concentrations, or N uptakes significantly different from those obtained with their unamended surface-applied counterparts in the one year that each was tested.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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