Resumo

CARRILLO ROMO, Regina et al. Inoculation and nitrogen fertilization for forage production in annual ryegrass, oats and wheat. Rev. mex. de cienc. pecuarias [online]. 2010, vol.1, n.2, pp.131-143. ISSN 2448-6698.

The objectives were evaluating the combined effects of different rates of both inoculum (Rhodococcus fascians) and nitrogen on forage production of grasses and to perform a cost - benefit economic analysis. The species analyzed were Avena sativa L, Lolium multiflorum Lam, and Triticum durum L through the following treatments: inoculation, nitrogen fertilization (0, 30, 60 kg N ha^-1) and a combination of inoculation and fertilization. The species were established under irrigated conditions in a clay loam soil with 6.7 pH, and 0.34 % organic matter. The microorganism was sprayed on the seed and later, on the plants after each forage harvest. Forage production was evaluated in terms of metric tons (t) of dry matter (DM) ha-1. The economic study was performed using marginal analysis, where the indicators were cost variables, forage production and net benefits. The experiment was carried out using a completely randomized design with a 2x3x3 factorial arrangement with four replications, where the first factor was inoculation; the second factor, species; and the third factor, N rate. The results show that the combined use of an inoculum and 30 kg N ha^-1 produces 50 % more DM (approximately 11 t) than when only N is used, especially in Avena sativa L. and Lolium multiflorum Lam. The economic analysis showed that the best treatment was inoculation plus 30 kg N ha-1 for Avena sativa L, presenting a marginal return rate of over 60 %.

Palavras-chave : Inoculum; Fertilization; Avena sativa; Triticum durum; Lolium multiflorum; Forage production; Rodococcus fascians; Economic analysis; Cost - benefit.