COMPARATIVE EFFICACY OF UREA FERTILIZATION VIA SUPERGRANULES VERSUS PRILLS ON NITROGEN DISTRIBUTION, YIELD RESPONSE AND NITROGEN USE EFFICIENCY OF SPRING WHEAT

Abstract

The impact of urea prills (1–2 mm) versus urea supergranules (USGs, ∼10 mm), placed at different depths, on the growth and nitrogen (N) use efficiency of spring wheat was investigated under greenhouse conditions. The amount of fertilizer ¹⁵N derived from either form was 50% greater in the top soil than at lower depths. The comparatively slower release and distribution of USG-N resulted in enhanced dry matter production and fertilizer-N uptake during the later growth stages that were also associated with a higher translocation of fertilizer-¹⁵N into the grain (34.9% versus 28.7% for the prills). Deeper placements of USGs (5.0–7.5 cm) resulted in greater fertilizer-N recovery in the crop (70.5–78.0%) compared to the use of prills (56.6%). Our results strongly suggest that the proper application of USGs can increase yields and fertilizer-N utilization of wheat and simultaneously decrease N losses compared to equivalent use of prills, and therefore presents important agronomic advantages.

Keywords:

• ¹⁵N-urea
• urea granule sizes
• N use efficiency
• spring wheat
• priming effects

ACKNOWLEDGMENTS

We gratefully acknowledge the Alexander von Humboldt Foundation, Germany for awarding a research fellowship to the senior author to carry out this research. We thank Mrs. Christine Haas and Claudia Schütz for providing analytical support in the laboratory and Mr. Reinhold Manhart for his help in conducting these experiments. We also thank Professor Olaf Bininda-Emonds for improving the English of this manuscript.

Notes

*Ndff_c = nitrogen derived from fertilizer in crop; FNR_c = fertilizer N recovery by crop; PU = urea prills; USG = urea supergranule; LSD_0.05 = least significant difference at 5% level. Crop parameters followed by the same letter do not vary significantly to one other.