Abstract:
This study evaluated the effectiveness of using Streptomyces naganishii, a
phosphorus-solubilizing bacteria (PSB), with Eppawala Rock Phosphate (ERP) as a
potential replacement for Triple Super Phosphate (TSP) in maize cultivation. The
experiment was conducted at the Sustainable Agriculture Research and Development
Center, Makandura. The design of the field experiment was a randomized complete
block design (RCBD) with nine treatments and three replicates. Treatments included
T1 as a control (100% DOA recommendation + Compost 10 t ha-1, T2 (70% DOA
recommendation + Compost 10 t ha-1), T3 (70% DOA without TSP + Compost 10 t
ha-1), T4 (T3 + ERP 0.2 t ha-1), T5 (T4 + bio fertilizer PSB), T6 (T3 + PSB), T7
(Compost 20 t ha-1 + ERP + PSB), T8 (Compost 20 t ha-1 + PSB), and T9 (no
fertilizer). Results indicated that T2 achieved the highest seed yield at 10.3 t ha⁻¹,
followed by T5 with 9.95 t ha⁻¹, significantly surpassing (p<0.05) the control, which
reported 9.8 t ha⁻¹. This indicates that ERP combined with PSB could provide a viable
alternative to TSP for optimizing seed yield. Treatment 5 demonstrated a considerable
increment in root volume and cob girth, highlighting the beneficial effects of ERP and
PSB on nutrient uptake. Treatments with PSB and ERP reported high postharvest
phosphorus availability, indicating long-term soil health benefits. The study
concludes that ERP combined with Streptomyces naganishii offers an effective
substitute for TSP, reducing reliance on imported fertilizers and supporting
sustainable maize production in phosphorus-limited soils.
