INFLUENCE OF NANO-ZINC OXIDE-ENRICHED BIOCHAR COMPOSITE ON THE PHYSICOCHEMICAL PROPERTIES OF CALCAREOUS SOILS AND SORGHUM (Sorghum bicolor L.) GROWTH

Abstract

This investigation sought to assess the impact of zinc oxide-enriched biochar nanoparticles on soil characteristics, nutrient assimilation, and the growth of sorghum in calcareous soils. The biochar was synthesized from a mixture of cattle manure and sesame straw via a slow pyrolysis process conducted at 400°C for a duration of 70 minutes under oxygen-limited conditions. Subsequent to its production, the biochar was analyzed for several parameters, including electrical conductivity, pH, organic matter content, organic carbon concentration, carbon-to-nitrogen ratio, and cation exchange capacity. Nano zinc oxide was incorporated into the biochar matrix at a concentration of 5%. Utilizing a completely randomized design, various treatments comprising 0, 1, 3, and 5% biochar-ZnO composites were introduced to the soil contained within 20 cm diameter plastic pots, which were subsequently planted with sorghum. The findings revealed notable enhancements in soil pH, electrical conductivity, organic carbon levels, and nutrient availability (including nitrogen, phosphorus, zinc, potassium, and iron), with the treatment containing 5% ZnO-enriched biochar nanoparticles demonstrating the most pronounced effects. In parallel, metrics such as plant height, biomass accumulation, chlorophyll concentration, protein content, and nitrogen levels exhibited significant increases corresponding to elevated application rates. These results indicate that the incorporation of ZnO-enriched biochar nanoparticles has the capacity to enhance growth metrics and soil fertility, thereby presenting a viable approach for promoting sustainable agricultural practices in nutrient-impoverished, particularly zinc-deficient, calcareous soils.