Influences of silicate fertilizers containing different rates of iron slag on CH4 emission and rice (Oryza sativa L.) growth

Methane (CH 4 ) is an important greenhouse gas, with a short-term greenhouse effect 80-fold that of carbon dioxide.Blast furnace slag used as a base ingredient for silicate fertilizer, and contained Fe 3+ , which acts as reduction of CH 4 emissions in flooded rice paddy.This study was evaluated the effects of the silicate fertilizer with different rates of the iron slag on CH 4 emissions and rice growth.In this study, the SF 0.0% was applied with silicate fertilizer containing 0.0% of the iron slag, while the SF 2.5% and SF 5.0% were treated with silicate fertilizer containing 2.5 and 5.0%, respectively.The CH 4 emissions during rice cropping period were assessed using a closed-chamber method and then determined by Gas chromatography.The CH 4 fluxes were reduced by 17% (SF 0.0%), 17% (SF 2.5%), and 8% (SF 5.0%) compared to the treatment with only-inorganic fertilization (control).Conversely, rice grain yield increased by 15 -30% compared to the control owing to the improvement of soil quality by silicate fertilization.In particular, soil pH, available phosphorus and available silicic acid content were increased with the increase in the iron slag rates from 0.0 to 5.0%.These contributed to a significant increase in rice growth such as 1,000-grains weight and percentage of filled grains.Consequently, these findings were indicated that the application of silicate fertilizer containing 2.5 -5.0% of iron slag would be the most effective in both CH 4 reduction and rice growth.