Combined Application of Rice Husk Biochar and Lime Increases Phosphorus Availability and Maize Yield in an Acidic Soil

Biochar, a pyrogenic carbon, has been receiving incremental attention for potential contribution to soil health, agricultural productivity enhancement while mitigating climate change by sequestering carbon and reducing greenhouse gas (GHG) emissions. However, it is not well-known to us how far rice husk biochar (RHB) application rates could increase phosphorus (P) bioavailability and plant performance when co-applied with P and lime. Here, we present data of a pot experiment consisting of eleven treatments to evaluate RHB, lime, and phosphorus effect on soil phosphorus availability, CO2 emission, nutrient uptake, and yield performance of maize. Co-application of RHB (10 and 15 t ha−1) and lime (100% and 75%) was made with different rates of P (100%, 75%, and 50%). Our result revealed that, at harvest, the combined application of RHB, lime, and phosphorus fertilizer significantly increased soil pH, P availability and decreased Al and Fe toxicity relative to the control while increasing maize yield. The maximum soil pH increased by 36.75%, the highest available P increased by 158.75%, whilst, the exchangeable Al content reduced by 96.84% compared to the control treatment. However, the difference in biomass production and yield among different lime, RHB, and P were minimal, with the largest grain yield (15.50 t ha−1) was recorded in the T6 treatments (75% lime + 10 t ha−1 RHB + 100% Triple superphosphate). The increment in biomass and grain yield could have occurred due to lime and RHB mediated changes in soil properties, including enhancement of soil pH, availability of P, and other nutrients. This increased availability then increased nutrient uptake and biomass production. Our results suggest that the combined application of lime and RHB could bring favorable changes in soil properties while sacrificing some carbon from soils.