The use of rice husk charcoal in agriculture is expected to reduce greenhouse gas emissions and support sustainable agricultural production. While numerous studies have examined the soil-improvement effects of rice husk charcoal, few have quantified its effects on plant growth, soil nutrients, and microbial activity simultaneously for a comprehensive assessment of these factors as a plant-soil system. In this study, a three-week experiment was conducted, in which soybean seedling growth (above-ground and root biomass), soil chemical properties (soil pH, total carbon, total nitrogen, plant-available phosphorus, exchangeable potassium), and soil microbial biomass (microbial biomass carbon, microbial biomass nitrogen) following the addition of rice husk charcoal to soil.
The results showed that soybean seedling growth and microbial biomass were higher in soil amended with rice husk charcoal. Furthermore, the addition of rice husk charcoal significantly increased soil pH, total carbon, and exchangeable potassium cation concentrations. These results indicate that adding rice husk charcoal to soil improves plant growth, soil properties, and microbial abundance.