Nitrogen and molybdenum fertilization and inoculation of common bean with Rhizobium spp. in two oxisols

Adubações nitrogenada e molíbdica e inoculação com Rhizobium spp. no feijoeiro-comum em dois latossolos

ABSTRACT.

The aim of this study was to evaluate the effects of foliar application of molybdenum and small dose of nitrogen at planting on common bean production when using seed inoculation with rhizobia. Two field experiments were conducted, applying a randomized block design and a factorial arrangement (3x2x2) + 1, with three replicates. Treatments consisted of inoculation with Rhizobium spp. (strain CIAT 899^T, strain UFLA 02-100, and uninoculated), foliar application of molybdenum (0 and 80 g ha^-1), and fertilization with N-urea at planting (0 and 20 kg ha^-1), with an additional N treatment of 40 applied at planting and 40 kg ha^-1 applied as topdressing. The foliar application of molybdenum did not favor the nodulation, but its effect on yield was dependent on the chemical soil characteristics, providing highest yield in soil at Patos de Minas with pH more acid and with higher phosphorus and organic matter concentrations. Small dose of nitrogen applied at planting did not reduce nodulation of bean inoculated with rhizobia, but it can reduce the seeds emergence, thus negatively affecting yield. The native rhizobia promoted nodulation, the plant growth, shoot N accumulation and yield similar to the treatments that received inoculations of rhizobia strains.

Keywords:
Phaseolus vulgaris L.; biological nitrogen fixation; nutrients.