ABSTRACT Brazil is known for its extensive livestock production in pastures, supporting the world's second‐largest herd of cattle and being the leading beef exporter. However, livestock farming in Brazil has frequently been associated with soil degradation and greenhouse gas (GHG) emissions. We evaluated the effects of using plant growth‐promoting (PGPR) elite strains of Azospirillum brasilense and Pseudomonas fluorescens to improve pastures of Urochloa ruziziensis (Ruzi grass) and Megathyrsus maximus (Zuri guineagrass). A 2‐year field study was performed with both grasses to assess the effects of inoculation on soil enzyme activity, root traits, forage mass and nutritive value. In the first year, inoculation was via seed treatment; in the second, foliar spraying was used on the same treatments. Inoculation of U. ruziziensis with A. brasilense and P. fluorescens improved root traits related to water and nutrient uptake, including root dry weight, length density, volume, and root‐hair incidence. A. brasilense increased U. ruziziensis forage accumulation by 10.3%, while M. maximus increased 9.2% with P. fluorescens . Remarkable increases were observed for U. ruziziensis inoculated with A. brasilense in the nutrient content and for M. maximus inoculated with P. fluorescens , with average increase by 21.4% for N, 22.8% for P, and 10% for K. These results demonstrate the potential of PGPR to enhance tropical pasture production but highlight the need to study specific host genotype–PGPR interactions. Given the limited global efforts in sustainable tropical pasture strategies, PGPR may provide a feasible alternative to increase production efficiency.
Guimarães et al. (Thu,) studied this question.