Eco-friendly utilization of rice husk ash for amending acid soils

Rice husk ash (RHA) contains appreciable amounts of exchangeable cations and plant nutrients which can be used as liming material for acid soil reclamation. Hence, the present study was carried out to assess the potential of rice husk ash for soil acidity reclamation and its effect on related soil properties. RHA was collected from a modern rice mill and its physical and chemical properties were assessed. The results confirmed the alkaline nature of RHA with a pH of 8.30 at 1:10 RHA-to-water suspension. An incubation experiment was conducted with five levels of RHA viz., 10, 20, 30, 40 and 50 t ha-1; compared with the treatments without liming material and the lime application as per lime requirement. Soil sampling was performed at 15, 30, 45 and 60 days after incubation (DAI) and analysed. The results indicated that the application of RHA 50 t ha-1, 40 t ha-1,30 t ha-1 and lime (100% lime) were comparable in enhancing the soil pH, effective cation exchange capacity and percent base saturation and reduced the total acidity and exchangeable Al. With all levels of RHA and lime application, favourable effects on soil properties related to acidic soil reclamation were observed over time. Exchangeable Ca and Mg were the highest in the 100% lime requirement, followed by RHA at 50 t ha-1. Exchangeable K and Na were the highest in rice husk ash at 50 t ha-1. The results emanated from this study ensured the potential of rice husk ash as a source of lime for acidic soils reclamation.