2014 年 5 巻 1 号 p. 58-64
Today biochar research in agriculture is worldwide interested to mitigate greenhouse gas emission. Application of biochar in anoxic condition to different textured paddy soils was proposed to study. We gave hypothesis that biochar rates in paddy soils will correlate to the changing of CH4 production, soil labile organic carbon (LOC), pH and electrical conductivity (EC), and their interactions. Biochar amendment rates, 6.25, 12.50, 18.75 and 25 t ha-1 were anaerobically incubated in loamy, clayey and loamy sand soils for 28 days. At the end of incubation, biochar amended loamy soils gave the highest cumulative CH4 production followed by clayey and loamy sand soils. CH4 production was enhanced by biochar amendment in loamy and clayey, but suppressed in loamy sand. The highest cumulative CH4, 47.03 mg CH4-C kg-1, was produced from loamy soil with 12.50 t ha-1 of biochar. The highest LOC was in clayey soil followed by loam and loamy sand in all rates of biochar amendment. Biochar had tendency to enhance soil pH in loam, but not in clay and loamy sand. In addition, highest EC was in clay, especially with 25 t ha-1 of biochar amendment, followed by loam and loamy sand. Through the whole of incubation, biocahar amendment rates significantly negative correlated to CH4 production rates in all soil textures. The positive correlations between LOC and biochar rates were found in clayey and loamy sand soils, while the former was highly significant. However, fluctuated correlations were manifested in loamy soil. Furthermore, in loamy sand, the stronger correlation between biochar rates, and both pH and EC, compared to loamy and clayey soils. Biochar amendments suppressed CH4 production in loamy sand, but enhanced in loamy and clayey soil under anaerobic incubation. Further studies on biochar feasibility should be trialed in paddy-field condition.
