Corn yield response to polymer and non-coated urea placement and timings

Document Type: Research Paper


1 Dept. of Soil, Environmental and Atmospheric Sciences, Univ. of Missouri, Columbia, MO 65211.

2 Div. of Plant Sciences, Univ. of Missouri, Novelty, MO 63460.


Poorly drained claypan soils can increase the importance of tillage and N
management for corn (Zea mays L.) production. Field research in 2008, 2009 and
2010 (high rainfall years) near Novelty, MO (40° 1' N, 92° 11' W) sought to
determine the effect of polymer-coated urea (PCU) placement [strip-tillage (ST) deep
banded and no-till (NT) broadcast] and application timing (fall, early preplant and
preplant) on red clover (Trifolium pratense L.) biomass and corn response compared
to non-coated urea (NCU) and anhydrous ammonia (AA) in the presence and
absence of nitrapyrin a nitrification inhibitor. Strip-tillage reduced clover dry weights
20% in 2008 and 2009 and early preplant ST reduced dry weights 40 to 45% in 2010
compared to NT. Corn plant population was 8,100 to 8,400 plants ha-1 greater with
ST compared to NT. Preplant applications of AA plus nitrapyrin, AA, ST placement
of PCU and NCU increased grain yields 1 to 1.2 Mg ha-1 compared to fall
applications of these fertilizer sources. Fall and preplant ST placement of PCU
increased grain yields 1.2 Mg ha-1 compared to NCU. Strip-till placement of PCU
and NCU increased yields 2.1 to 3.2 Mg ha-1 over broadcast applications of these
fertilizer sources. Strip-till placement of PCU synergistically increased yield over
NCU and broadcast applications of PCU or NCU due to increased stands and
possibly due to better plant utilization of the banded N fertilizer utility.