Deciphering the Impact of FOMI Organo-Mineral Fertilizers on pH and Organic Carbon of the Soils under Tobacco Production in Tanzania

A study was conducted in selected tobacco producing areas in Tanzania to evaluate the impact of FOMI organo-mineral fertilizers on soil pH and soil organic carbon levels after harvesting the tobacco crop K326 from the three sites of Tumbi-Tabora, Mtanila-Chunya and Ushetu-Shinyanga in 2023/24 cropping season. The experiment involved eight treatments: an unfertilized control; standard NPK fertilizers at 500 kg ha ^-1 and CAN at 133 kg ha ^-1 ; FOMI SUPA applied at 1000, 800, and 600 kg ha ^-1 on day 7, combined with FOMI CANS at 133, 83, and 67 kg ha ^-1 on day 21; and FOMI GREEN at 650, 517, and 383 kg ha ^-1 on day 7, combined with FOMI NENEPESHA at 233, 183, and 133 kg ha ^-1 on day 21. Results showed that all FOMI fertilizers improved soil pH at all application rates without significant differences between them. The soil organic carbon content improved significantly ( p =0.001 ) to 0.21 ± 0.00% from the initial level to the depth of 20 cm when FOMI SUPA (T3) was applied at 1000 kg ha ^-1 on day 7 and FOMI CANS at 133 kg ha ^-1 on day 21. Other treatments, including FOMI SUPA (T4) at 800 kg ha ^-1 and FOMI GREEN (T6) at 650 kg ha ^-1 , improved organic carbon to 0.20 ± 0.00%, without significant differences. Conclusively, FOMI fertilizers are effective in improving soil pH and organic carbon, highlighting their potential for sustainable use in tobacco cultivation, enhancing soil health.