SUMMARY
A form of increasing the efficiency of N fertilizer is by coating urea with
polymers to reduce ammonia volatilization. The aim of this study was to evaluate
the effect of polymer-coated urea on the control of ammonia volatilization, yield
and nutritional characteristics of maize. The experiment was carried out during
one maize growing cycle in 2009/10 on a Geric Ferralsol, inUberlândia, MG, Brazil.
Nitrogen fertilizers were applied as topdressing on the soil surface in the following
urea treatments: polymer-coated urea at rates of 45, 67.5 and 90 kg ha-1 N and one
control treatment (no N), in randomized blocks with four replications. Nitrogen
application had a favorable effect on N concentrations in leaves and grains, Soil
Plant Analysis Development (SPAD) chlorophyll meter readings and on grain yield,
where as coated urea had no effect on the volatilization rates, SPAD readings and
N leaf and grain concentration, nor on grain yield in comparison to conventional
fertilization.