SUMMARY The objective of this work was to study the combination of Azospirillum argentinense Az39 with pre and post-emergent herbicides, Acetochlor and Dicamba, for its application both in vitro, and in germination and vegetative stage in maize plants. Az39 survival was determined in the presence of the herbicides added to the culture medium, with and without the addition of carbon or nitrogen sources. In maize seeds, treated with both herbicides, with and without bacterial inoculation, the effect on early development and morpho-physiological variables in stage V5 was evaluated. The tests determined that Az39 survived the presence of both herbicides and used Dicamba as a carbon source. The germination percentage decreased when Acetochlor was applied, while Dicamba inhibited root development. In V5, a decrease in the dry weight of the aerial and root parts of plants treated with Acetochlor was observed, even in the presence of Az39. Bacterial inoculation and/or herbicide application did not show changes in membrane damage, total chlorophylls and carotenoids. This new knowledge promotes the use of native bacterial strains that promote plant growth for their complementary benefits in the development of sustainable practices in crop production.

RESUMEN El objetivo de este trabajo fue estudiar la combinación de Azospirillum argentinense Az39 con herbicidas pre y post-emergentes, Acetoclor y Dicamba, para su aplicación tanto in vitro como en germinación y estadio vegetativo en plantas de maíz. Se determinó la supervivencia de Az39 en presencia de los herbicidas agregados al medio de cultivo con y sin la adición de fuentes de carbono o nitrógeno. En semillas de maíz, tratadas con ambos herbicidas con y sin la inoculación bacteriana, se evaluó el efecto en el desarrollo temprano y variables morfosiológicas en estadio V5. Los ensayos determinaron que Az39 sobrevivió a la presencia de ambos herbicidas y utilizó a Dicamba como fuente de carbono. El porcentaje de germinación disminuyó con la aplicación de Acetoclor, mientras que Dicamba inhibió el desarrollo radical. En V5, se observó una disminución del peso seco de la parte aérea y radical de las plantas tratadas con Acetoclor, aun en presencia de Az39. La inoculación bacteriana y/o la aplicación de herbicidas, no evidenciaron modificaciones en el daño de membranas, clorofilas totales y carotenos. Estos nuevos hallazgos promueven el empleo de cepas bacterianas nativas promotoras del crecimiento vegetal por sus beneficios complementarios en prácticas sustentables en la producción de cultivos.

The aim of this research was to estimate the leaf and twig temperature and moisture content of yerba maté branches (Ilex paraguariensis Saint Hilaire) during heat treatment, carried out in a rotary kiln dryer. These variables had to be estimated (modeling the heat and mass transfer) due to the difficulty of experimental measurement in the dryer. For modeling, the equipment was divided into two zones: the flame or heat treatment zone and the drying zone. The model developed fit well with the experimental data when water loss took place only in leaves. In the first zone, leaf temperature increased until it reached 135°C and then it slowly decreased to 88°C at the exit, despite the gas temperature, which varied in this zone from 460°C to 120°C. Twig temperature increased in the two zones from its inlet temperature (25°C) up to 75°C. A model error of about 3% was estimated based on theoretical and experimental data on leaf moisture content.