Methane emission mitigation in paddy field utilizing rice husk biosilica

The increasing of paddy production give an environmentally impact, because paddy cultivation contributes 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 root oxidation power of paddy, thus it will reduce methane emissions. The objective of this research was to evaluate the reduction of methan emissiom from paddy field by using silica from rice husk. This research used experiment with randomized block design and has eight treatments with three repetitions. The dose of biosilica is equivalent with 200 kg ha-1 of ameliorant in the form of ash, biochar, and compost. The methane analysis was carried out at 1, 5, 8, 12, and 15 weeks after planting. The methane was analized by GC with FID. The result of the research show that the ash produced from rice husk is 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) can increase the paddy growth and paddy production as well as reduce methane emissions effectively. The reduction of methane emission by giving silica into the soil is happened through the dissolved silica mechanism. The dissolved silica causes the increasing of pH and the root oxidation power of paddy.