Long-life inoculation contributes to current brazilean soybean production

BUSO, P.H.M; BONFANTE, F G; RAMOS, MARÍA LAURA; DIAZ ZORITA, MARTIN

Puerto Varas. Región de Los Lagos. Chile

Congreso; RELAR2019- XXIX. Reunión Latinoamericana de Rizobiología; 2019

Fac. de Ciencias Agropecuarias y Forestales, Universidad de La Frontera - Centro Biotecnologico de Estudios Microbianos, CEBEM

SUMMARY: Under field conditions of Paraná, Goiás and Mato Grosso States of Brazil, this work pursued to establish the contribution on soybean productivity of seed inoculated with Bradyrhizobium elkanii strains applied at different days of pretreatment before planting. In the 2017/18 season, fifty soybean field trials with seven seed treatments were established [i) seeds without inoculation; ii) fertilization with 200 kg ha-1 N without rhizobia inoculation; iii) seeds inoculated with rhizobia at planting; iv) to vii) seeds inoculated with rhizobia and biological protectants applied at planting and at approximately 38, 52 and 66 days before planting. All the treatments where in combination with five seed treatments using the following active ingredients: Imidacloprid, Thiodicarb; Carbendazim, Thiram; Chlorantraniliprole; Cyantraniliprol; Abamectin; Thiametoxan; Metalaxyl-M, Fludioxonil; Fipronil, Pyraclostrobin, Thiophanate-metyl. Plant nodulation and grain yield components were evaluated, and the data analyzed based on ANOVA and regression procedures. Also, in the 208/19 season, 62 strips plots comparing inoculation at planting and long-term before planting were established at grower?s management conditions. Independently of the moment of inoculation, the combined use of the inoculant with a specific formulated protectant, provided greater responses in nodulation (increased 10.4% the nodules located on the main root) and increases 212 kg ha-1 (6.1 %) the mean grain productivity compared with the non-inoculated control. The field strips also showed 18.1 % more main root nodules with positive responses in 79% of the sites. These results validated that pretreatment of seed with inoculant from 26 to 78 days before planting, using a formulation containing strains of Bradyrhizobium elkanii, combined with different chemicals and a specially formulated microbial protectant, is as effective as the inoculation applied at planting, under regular current Brazilian soybean crops.