Resposta produtiva do fracionamento de nitrogênio em genótipos de arroz na fronteira oeste do Rio Grande do Sul

Abstract

Nitrogen fertilization is one of the main pillars to occur maximum response in the productive potential of each rice genotype. Differences in the application in whole or fractional dose of nitrogen in rice genotypes may form themselves into promising strategy to maximize the best use of this macronutrient. The objective of this study was to evaluate the productive response regarding full or fractional application of nitrogen in different growth stages of hybrid and conventional rice genotypes on the western border of Rio Grande do Sul. The experiment was conducted in two growing seasons 2013/14 and 2014/15, assessing six genotypes of rice, four hybrids (Avaxi Cl, Inov Cl, Cl XP 102, XP 111 Cl) and two conventional cultivars (PUITA Inta Cl and Guri Inta Cl), being subjected to the division of the application of nitrogen (N). The Fractionation is in three ways: i) an application (100% N) in dry soil 15 days after emergence; ii) two applications (70% + 30% N) being the first in dry soil with 15 DAE and the second in the differentiation of floral primordia; and iii) three applications (50% + 30% + 20% N) the first without dry soil with 15 DAE, the second in the DPF and the third at the end of flowering. The fractionation factor and its interaction with genotype, crop, and genotype x crop were not significant. Thus, the application of nitrogen in a whole or in divided doses two or three times does not differ. Thus a complete application before the water intake is an alternative to reduce production costs for farmers. The genotype x season was significant in the harvest 2013/14 the effect of genotype was significant for the variable grain yield, with the hybrid XP 111 Cl superior to the other, as compared to the 2014/15 season, all hybrid genotypes They were higher than the conventional cultivars.