title: Inoculation of Bacillus sphaericus UPMB-10 to young oil palm and measurement of its uptake of fixed nitrogen using the ¹⁵N isotope dilution technique.
abstract: 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. sphaericus inoculation had significantly lower ¹⁵N enrichment than uninoculated palms that received similar N fertilizers. The dilution of labeled N served as a marker for the occurrence of biological N₂ fixation. The proportion of N uptake that was derived from the atmosphere was estimated as 63% on the whole plant basis. The inoculation process increased the N and dry matter yields of the palm leaflets and rachis significantly. Field planting of young, immature oil palm in soil inoculated with B. sphaericus UPMB-10 might mitigate inorganic fertilizer-N application through supplementation by biological nitrogen fixation. This could be a new and important source of nitrogen biofertilizer in the early phase of oil palm cultivation in the field.
authors.affiliation: Faculty of Agriculture, Universiti Putra Malaysia, Malaysia.
authors.forename: Fitri Abdul Aziz
authors.initials: FA
authors.lastname: Zakry
authors.forename: Zulkifli H
authors.initials: ZH
authors.lastname: Shamsuddin
authors.forename: Khairuddin
authors.initials: K
authors.lastname: Abdul Rahim
authors.forename: Zin
authors.initials: Z
authors.lastname: Zawawi Zakaria
authors.forename: Anuar
authors.initials: A
authors.lastname: Abdul Rahim
mesh_terms: D028023:Arecaceae / Q000378:metabolism* / Q000382:microbiology*; D001407:Bacillus / Q000378:metabolism* / Q000502:physiology; D007553:Isotope Labeling; D009584:Nitrogen / Q000378:metabolism*; D009586:Nitrogen Fixation
chemical_list: D009584:Nitrogen