Co-inoculation of Bradyrhizobium and Azospirillum in soybean after pasture in Cerrado

Abstract

The crop-livestock integration system (ILP) stands out as a viable production alternative for the recovery of degraded areas, integrating the crop and livestock components, in rotation, consortium or succession, in the same area. One of the advantages of the system is to increase productivity in a sustainable way, both in the No-tillage System (SPD) and in the conventional system. Also noteworthy are the beneficial effects on the physical, chemical and biological properties of the soil, where its physical quality can be improved with the use of pastures for animals in farming areas, or as a straw-forming plant for subsequent cultivation. Pastures of the genus Urochloa (Syn. Brachiaria), mainly of U. brizantha cv. Marandu plants produce forage under conditions of low water availability and for a longer period, leaving more straw for continued no-till, however, due to their high C / N ratio may lead to a temporary immobilization of N to the plants in succession. Thus diazotrophic bacteria such as Azospirillum have been used for co-inoculation of soybean, together with symbiotic bacteria Bradyrhizobium, as an alternative to assist in the availability of greater amount of nutrients to the plants, due to the effect of greater root growth. Therefore, the research work will aim at evaluating the growth and productive performance of soybean in succession to the marandu grass submitted to three managements in a Oxisol, under dry conditions, in the Cerrado: fertilized with 50 kg ha-1 of N (A total of 5 cuts with 250 kg ha-1 of N), with leaf spraying at each cut with Azospirillum brasilense and in a condition without nitrogen fertilization or spraying with the diazotrophic bacteria after each cut, and In two soybean seeding conditions: inoculated only with Bradyrhizobium or co-inoculated with Azospirillum brasilense. (AU)