Mitigation methane emission in paddy field utilizing biosilica of rice husk

The increasing of paddy production has environmental impact because paddy cultivation contributes to 46.2% of the total greenhouse gas emissions from agriculture. The paddy cultivation emission amounted to 76% of methane. Meanwhile, the grain produced by paddy consists of 16.3% to 28% husk with 18 to 22.3% silica. Silica contained in the soil can increase the oxidation power of paddy root, thus it will reduce methane emissions. The objective of this research was to evaluate the reduction of methane emission from paddy field by using silica from rice husk. This research used an experiment with randomized block design based on eight treatments with three repetitions. The dose of biosilica was equal to 200 kg ha^-1 of ameliorant in the form of ash, biochar, and compost. The methane analysis was carried out in 1, 5, 8, 12, and 15 weeks after planting. The methane was analized by GC with FID. Results showed that the ash produced from rice husk was the best single source of biosilica in paddy soil that can reduce methane emissions by 80.75%. The composition of ash, biochar, and compost (1:1:1) could increase the paddy growth and paddy production and reduce methane emissions effectively. The methane emission was reduced by adding silica to the soil through the dissolved silica mechanism. The dissolved silica increased pH and the root oxidation power of paddy.