Nitrogen Source, Rate, and Application Method for No-Tillage Corn
1989
Howard, Donald D. | Tyler, Donald D.
Surface applying urea-containing N fertilizers may result in greater N losses by volatilization of NH₃ as urea hydrolyses than nonurea containing materials. The objective of this study was to evaluate the N efficiency of urea-ammonium nitrate (UAN), urea and urea-urea phosphate (UUP) at 56, 112, 168, and 224 kg ha⁻¹ N rates applied broadcast, surface banded, and injected for no-till corn (Zea mays L.). Yield, ear-leaf N concentration, and N uptake were used to estimate N availability. Broadcast ammonium nitrate (AN) and injected anhydrous ammonia (AA) were used as controls for evaluating N efficiency of urea-containing N sources and their application methods. The method of applying the urea-containing N sources has a significant effect on apparent N fertilizer availability. Injecting UAN and urea resulted in significantly higher yield, leaf N concentration, and N uptake when compared with broadcast and surface band application methods. Surface banding UAN at 168 and 224 kg ha⁻¹ resulted in higher yields than urea or UUP. Yield, leaf N concentration and N uptake differences among the three urea-containing N sources were not observed when broadcast applied. Broadcasting AN at 168 and 224 kg ha⁻¹ resulted in higher yields than UAN, urea or UUP. Injecting the N sources resulted in higher yields when compared with broadcasting AN. Research partially supported from funds provided by Fluid Fert. Found. and TVA.
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