NITROGEN FERTILIZATION IN CORN WITH DIFFERENT SOURCES OF NITROGEN

Abstract

Nitrogen is one of the nutrients most needed in greater quantity by the corn crop, the coverage system that precedes it must be designed in order to avoid losses, in addition to having the capacity to supply external nitrogen to the system. The objective of this work is to analyze which source of N provides greater productivity with nitrogen fertilization in corn in the second crop, regarding its sources and possibilities to reduce N loss. The experiment was carried out at Santana farm, Vianópolis, GO. The experimental design adopted was randomized blocks, with four treatments and four replications. The treatments were divided as follows: T1 – control, without the use of fertilizer; T2 – 267 kg ha^-1 of granulated urea and 100 kg ha^-1 of KCl; T3 – 267 kg ha^-1 of protected granulated urea and 100 kg ha^-1 of KCl; T4 – 445 kg ha^-1 of ammonium nitrate and 100 kg ha^-1 of KCl. Plant height, stem diameter and productivity were used as evaluation parameters. The results were submitted to analysis of variance, and when significant differences occurred, identified by the F test (P<0.05), Tukey's test of means was applied. There is no effect on corn productivity due to the protection of urea, as long as there are no water restrictions for the corn crop in the off-season. Ammonium nitrate does not perform better than urea, as long as there is no water restriction for safrinha corn. Nitrogen fertilization is essential for corn productivity.