Inoculation of Bacillus sphaericus UPMB-10 to young oil palm and measurement of its uptake of fixed nitrogen using the ¹⁵N isotope dilution technique.

There are increasing applications of diazotrophic rhizobacteria in the sustainable agriculture system. A field experiment on young immature oil palm was conducted to quantify the uptake of N derived from N₂ fixation by the diazotroph Bacillus sphaericus strain UPMB-10, using the ¹⁵N isotope dilution method. Eight months after ¹⁵N application, young immature oil palms that received 67% of standard N fertilizer application together with B.