Urea is the main nitrogen fertilizer used in topdressing in corn, however, it has a high susceptibility to N losses due to volatilization of ammonia. An alternative is the treatment of urea with urease inhibitor or coating with layers of polymers, classified as enhanced efficiency nitrogen fertilizers. In this context, the present study aimed to evaluate the application of increasing rates of enhanced efficiency nitrogen fertilizers and urea topdressing in corn. A randomized block design was used in a factorial scheme 3 x 4 + 1. The following sources were tested: common urea, urea treated with urease inhibitor and polymer coated urea, tested at rates of 32.5, 65, 130 and 260 kg ha-1 of N. The mass of one hundred grains and shoot dry weight increased linearly with rates of N. The nitrogen content in the leaf and corn yield were higher in case of urea treated with urease inhibitor or coated with polymers, especially at rates of 130 and 260 kg ha-1 of N. In this context, the use of enhanced efficiency nitrogen fertilizers not only improves the supply of N to the corn but also increases the grain yield.
Zea mays; ammonia volatilization; urease inhibitor (NBPT); polymers coated fertilizers; grain yield
