AGRONOMIC EVALUATION OF NITROUSNITRIC OXIDE EMISSION BY SOYBEAN INOCULATED WITH BRADYRHIZOBIUM STRAINS COMMONLY USED AS BIOFERTILIZERS IN SOUTH AMERICA

OBANDO M; ANTONELLI C.; CASANAVE S.; MAGUIRE V.; TORRES D.; PEREZ M.G.; BAILLERES M.A.; DONADIO F.; CREUS C.; VIDELA C.; PUENTE M.; ZILLI J.; ALVES B.; RUIZ O.A.; BEDMAR E.; CASSAN F.

PLANT AND SOIL

SPRINGER

Lugar: Berlin; Año: 2022 vol. 472 p. 311 - 328

0032-079X

Nitrous oxide (N2O) contributes to greenhouse gas (GHG) emissions and global warming, and agricultural soils represent the largest source of N2O emissions globally. Argentina and Brazil are among the most important soybean world producers; nitrogen nutrition of this legume usually depends on biological nitrogen fixation by symbiotic bacteria belonging to Bradyrhizobium genus. While some Bradyrhizobium species can generate N2 from NO3− (complete denitrification), the vast majority of them carry out incomplete denitrification releasing inorganic N intermediates such as N2O. To know if there are differences among Bradyrhizobium species/strains in their GHG emissions and denitrifying capacity, some soybean productive parameters and N2O fluxes were quantified in soybean plants inoculated with 6 different strains commonly used for the formulation of soybean inoculants in Argentina and Brazil: Bradyrhizobium japonicum (E109 and CPAC15), Bradyrhizobium diazoefficiens (USDA110 and CPAC7), and Bradyrhizobium elkanii (SEMIA5019 and SEMIA587). B. japonicum caused the greatest increases in soybean growth and grain yield, but also led to higher N2O emissions compared to the rest of the inoculated treatments and the uninoculated control. Plants inoculated with B. diazoefficiens were those producing lower emission levels and lower effect on growth and yield, and B. elkanii led to intermediate responses. The identity of the strains inoculated was confirmed through the molecular analysis of nodule tissues.