Inoculation in the sowing furrows enhanced Bradyrhizobium japonicum competitiveness for soybean nodulation in the presence of naturalized soil rhizobial populations

LÓPEZ GARCÍA, SILVINA; ALEJANDRO PERTICARI; PICCINETTI, CARLOS; VENTIMIGLIA; ARIAS; DE BATTISTA; ALTHABEGOITI, MARIA JULIA; MONGIARDINI, ELIAS JAVIER; PÉREZ GIMÉNEZ, JULIETA; QUELAS, JUAN IGNACIO; LODEIRO, ANIBAL

AGRONOMY JOURNAL

Año: 2008

0002-1962

Trabajo enviado para su publicación, ver adjuntoRhizobial position in the soil profile in relation to developing soybean roots wasregarded as a main determinant in the problem of competition between inoculants andsoil rhizobia for root nodules occupation. Since soil inoculation might better distributeinoculant rhizobia in the surface soil than seed inoculation, we compared the competitive performance of Bradyrhizobium japonicum inoculated with equivalent doses in the sowing furrows or on the seeds. Comparisons were made for nodules occupation, grain yield, an N grain contents. The assays were carried out with three strains at two crop seasons covering four Argentinean soils with naturalized populations ranging from 1.0 104 to 6.0 105 soybean-nodulating rhizobia g of soil–1. As a general trend from the four field assays we observed that in-furrow inoculation gave mean increases of 50% in inoculant’s nodule occupancy and 9% in grain yield, both in relation to seed-inoculation. Grain N contents were similar, indicating that yield was defined at the grains number level.