Survival of Azospirillum brasilense after applying herbicides on Triticum aestivum L. Var. Altiplano

Abstract

Herbicides are widely used in agriculture and are applied in various amounts that may directly or indirectly influence on soil microorganisms and their processes. In order to evaluate the survival of inoculated Azospirillum brasilense in the Altiplano variety of wheat to the application of two types of commercial herbicides, an organochlorine and, the other organophosphorus, the present experiment was established in the Ecozone, of the University of the Americas-Puebla, Mexico, under greenhouse conditions in 2009. The seeds were inoculated before planting with Azospirillum brasilense and, the herbicides were applied 40 days after. The treatments were applied: 1) uninoculated plants (absolute control); 2) inoculation with Azospirillun (inoculated control); 3) inoculated with Azospirillum plus herbicide application 2, 4, D, (organochlorine); 4) inoculated with Azospirillum plus glyphosate herbicide application (organophosphate); 5) without inoculation and applying herbicide 2, 4, D; and 6) without inoculation and application of glyphosate, in a completely randomized design with ten replicates. The survival of the bacteria in the root system was recorded through the use of the most probable number technique, recording the plant height and weight. The results indicated that, the two herbicides (2, 4, D and glyphosate), did not signif icantly affected the population of Azospirillum in the root. Plants inoculated with the bacteria, with or without herbicide treatment showed increased in biomass compared to the non-inoculated plants. Biomass increased with application 2, 4, D.