Effects of rice straw biochar soil amendment on soil properties and environmental impact of opening burning

Abstract Traditional agricultural practices have various ecological and environmental challenges. This study examined the effects of rice straw biochar on the physico-chemical properties and water retention capacity of sandy soil under rain-fed lowland rice cultivation using FARO 44 and FARO 52 rice varieties. The study also considered the environmental impact of open-burning, emphasizing the need to transit to cleaner technology. The experiment was conducted using complete randomize experimental design. The biochar-soil mixture was applied at various rates (biochar: 0 g/5 kg, 20 g/5 kg, 60 g/5 kg, 100 g/5 kg, 120 g/5 kg) for the physicochemical characterization and replicated four times. 0 g/5 kg, 20 g/5 kg, 60 g/5 kg and 100 g/5 kg experimental mixture biochar and soil was used for water content and plant growth parameters experiments. The impact of biochar was assessed on various soil properties such as organic matter, soil bulk density, pH, cation exchange capacity (CEC), and macro-nutrients, also data on the plant performance such as tiller number, plant height, root biomass and shoot were collected. Statistical analysis was conducted on the result using analysis of variance, also significant means were separated using Tukey HSD test at 0.05 significance levels. The result revealed that the 100 g/5 kg treatment showed the best output, achieving 97.7% water retention and a pH of 7.00 ± 0.57. Both rice varieties had improved growth and biomass yield, with FARO 44 reaching an average plant height of 2.32 ± 0.46 m. The study also showed a significant reduction in the emission of the GHGS from adoption of biochar technology compared to open field burning method indicating a more environmentally friendly method of disposing the rice straw. These results highlight rice straw biochar as a sustainable soil amendment that improves sandy soil fertility, environmental friendly and enhances rice productivity.