Аннотация:Using enhanced efficiency fertilizers, such as polymer-coated urea (PCU), may be a good nitrogen (N) management option for increased corn (Zea mays L.) grain productivity, improved grain quality and N apparent recovery efficiency. The objective of this study was to evaluate the effect of N application timings (pre-emergence or topdress), N rates (0, 84, 126 and 168 kg N ha−1) and ratios of PCU with non-coated urea (NCU) (100:0, 75:25, 50:50, 25:75 and 0:100) on corn growth, grain yield, quality and N-use efficiency. Grain yield and protein concentration increased with increasing rates of N for both topdressed and pre-emergence timings. The topdressed treatments produced greater grain yields with higher grain protein concentration than pre-emergence applied treatments in most years. Grain N removal and apparent recovery efficiency was higher from topdressed than the pre-emergence timing. The use of PCU over NCU and topdressing over pre-emergence N application was evident.
