Resumo

MARCHESAN, Enio et al. Alternative sources of supply in the urea nitrogen for rice production. Cienc. Rural [online]. 2011, vol.41, n.12, pp. 2053-2059. ISSN 0103-8478.  http://dx.doi.org/10.1590/S0103-84782011001200003.

Urea is the main source of N used in agriculture, but has large losses in irrigated rice. The objective of this study was to evaluate the efficiency of N sources alternative to urea for use by rice applied at different stages of plant development through the quantification of N-NH₃ and agronomic parameters. The experiment was conducted in the field in the agricultural years 2007/08 and 2008/09. The experimental design was randomized blocks with four replications. The treatments consisted of different N sources applied at seeding, tillering and at the stage of floral differentiation: control without N, urea, urea + urease inhibitor, two sources of liquid N (N-28 and N-30) ammonium sulfate and urea + sulfur. In both seasons, the volatilization of N-NH₃ at seeding was almost negligible, whereas in the V4 stage, the source that was less volatilized was the ammonium sulfate. Yield response varied among years, probably due to the availability of N in the soil and climatic aspects. When economically advantageous, the use of urease inhibitor and ammonium sulfate provide yields similar to urea supply.

Palavras-chave : volatilization; urease inhibitor; ammonium sulfate; fertilizer fluids.