Augmentation of the fertilizer values of compost through beneficial microbes amid rock phosphate amendments during curing stage

Chemical and biological parameters of ninety days old rice straw compost under incubation were monitored through inoculation of nitrogen (N) fixing and phosphate solubilizing bacteria (PSB) amid rock phosphate (RP) amendments. The fertilizer values and biological stability of the compost produced during the bioprocesses were also assessed to evaluate the quality. Inoculation of nitrogen-fixing and PSB led to intense organic matter (OM) mineralization of the compost and stabilized the carbon to nitrogen (C: N) ratios of both solid (10.03–12.39) and liquid phase (0.09–0.05). The microbial biomass carbon (MBC) attained a range of higher values in between 4039.70 and 4424.61 μg./g./24hrs. and drop of respiration (13.66 μg. CO₂-C/g./24hrs.) indicate a good degree of maturity after incubation. Higher level of stabilized dehydrogenase (DH) (3543.36 and 3763.57μg.TPF/g./24hrs.), phosphomonoesterase (PMEase) (1746.40–3549.63 μg. p-nitrophenol/g./hr.) as well as fluorescein diacetate (FDA) hydro lase (4.13–7.42 μg. fluorescein/g./hr.) were observed at the end of the incubation period. Elevated and reasonably stabilized specific populations of Azospirillum (157.80–121.45 x10⁵ cfu./g.), Azotobacter (92.09–126.62 x 10⁵ cfu./g.) and PSB (7.79 x 10⁵ cfu./g.) at the end of incubation, were related to the added microorganisms. pH values stabilized in between 7.5 and 7.87, electrical conductivity (EC) drop off to 3.57 dS./m., cation exchange capacity (CEC) evolution to 55.42 c mol(p+)/kg. and NH₄⁺ -N shrinked to a minimum of 0.024%, during incubation. The additive strategy of N-fixing and PSB with RP incompost at curing stage visibly showed higher total N (1.85–1.97%), P (1.03–1.15%) and K(0.81–0.91%) in the final product.