Nitrogen Fertilizer Sources and Application Timing Affects Wheat and Inter-Seeded Red Clover Yields on Claypan Soils
1
Division of Plant Sciences, University of Missouri, Novelty, MO 63460, USA
2
Department of Soil, Environmental and Atmospheric Sciences, University of Missouri, Columbia, MO 65211, USA
3
Division of Plant Sciences, University of Missouri, Columbia, MO 65211, USA
*
Author to whom correspondence should be addressed.
†
These authors contributed equally to this work.
Agronomy 2014, 4(4), 497-513; https://doi.org/10.3390/agronomy4040497
Received: 7 October 2014
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Revised: 21 October 2014
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Accepted: 31 October 2014
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Published: 11 November 2014
(This article belongs to the Special Issue Towards a Better Understanding of Agronomic Efficiency of Nitrogen in Different Agro-Ecosystems)
Controlled-release N fertilizer, such as polymer-coated urea (PCU), may be a fall N management option for wheat (Triticum aestivum L.) grown in poorly-drained claypan soils. Field research evaluated (1) urea release from fall-applied PCU in 2006 and 2007; (2) broadcast fall-spring split (25%:75%) of N sources; and (3) a single fall (100%) application of PCU, urea, urea plus NBPT (N-(n-butyl) thiophosphoric triamide] (U + NBPT), ammonium nitrate (AN), or urea ammonium nitrate (UAN) at 0, 56, 84, and 112 kg·N·ha−1 on wheat yield, wheat biomass, N uptake by wheat, and frost-seeded red clover (FSC) (Trifolium pratense L.) forage yield (2004–2007). PCU applied in fall released less than 30% urea by February. Urea released from PCU by harvest was 60% and 85% in 2006 and 2007, respectively. In poorly-drained soils, wheat yields ranked PCU > AN > U + NBPT > urea ≥ UAN over the rates evaluated for fall-only application. PCU was a viable fall-applied N source, with yields similar to or greater than urea or U + NBPT split-applied. Split-N applications of AN, urea, UAN, and U + NBPT generally resulted in greater wheat yields than a fall application. Enhanced efficiency fertilizers provide farmers with flexible options for maintaining high yielding production systems.
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Keywords:
ammonium nitrate; cover crop; enhanced efficiency fertilizer; nitrogen; urea; urease inhibitor
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MDPI and ACS Style
Nelson, K.A.; Motavalli, P.P.; Nathan, M. Nitrogen Fertilizer Sources and Application Timing Affects Wheat and Inter-Seeded Red Clover Yields on Claypan Soils. Agronomy 2014, 4, 497-513. https://doi.org/10.3390/agronomy4040497
AMA Style
Nelson KA, Motavalli PP, Nathan M. Nitrogen Fertilizer Sources and Application Timing Affects Wheat and Inter-Seeded Red Clover Yields on Claypan Soils. Agronomy. 2014; 4(4):497-513. https://doi.org/10.3390/agronomy4040497
Chicago/Turabian StyleNelson, Kelly A., Peter P. Motavalli, and Manjula Nathan. 2014. "Nitrogen Fertilizer Sources and Application Timing Affects Wheat and Inter-Seeded Red Clover Yields on Claypan Soils" Agronomy 4, no. 4: 497-513. https://doi.org/10.3390/agronomy4040497
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