生物质炭施用量及水热条件对淹水土壤CO_2释放的影响

Effects of carbon dioxide emissions from waterlogged soils by biochar amendments and hydrothermal condition

通过模拟土柱实验,向水稻土中添加质量分数分别为0%(C0)、2%(C2)、5%(C5)、8%(C8)的生物质炭,并在不同淹水深度和温度下培养,旨在了解生物质炭的施用量及其水热条件对土壤CO2释放的影响,以期通过控制生物质炭的施炭量和改进农田管理措施,从而为农业温室气体碳减排提供依据.研究结果发现:施加生物质炭对土壤CO2释放的抑制作用明显,与对照相比,2%、5%、8%施炭量处理的土壤CO2累计释放量分别降低了5.1%、2.4%和26.5%.低施炭量对土壤CO2的释放降幅较少,而较高施炭量可能对抑制土壤CO2释放的效果更好;温度越高,土壤的呼吸作用越强,CO2释放速率也越快;在昼夜变化上,土壤夜间CO2的释放速率要高于白天;就淹水深度而言,土壤灌水深度愈深,CO2的释放速率愈低.此外,还从施炭量和水热条件对土壤CO2和CH4释放的综合排放效应进行了展望.

A waterlogged soil environment was simulated and added with mass fraction of 0 % （CO）, 2% （C2）, 5% （C5）, and 8% （C8） of biochar to paddy soils to realize the effects of carbon dioxide emissions by biochar amendments and hydrothermal condition under different irrigated water depths and culture temperature. It is aimed at decreasing agricultural green- house gases emissions by means of controlling biochar amendments and improving field management measures. The results showed that there is a significant inhibition of carbon dioxide emission from soils due to biochar amendment. Compared with the control, cumulative car- bon dioxide emissions from soils by biochar addition of 2%, 5%, and 8% were reduced by 5.1%, 2.4% and 26.5% respectively. In terms of inhibition of carbon dioxide emission from soils by biochar amendment, higher biochar amendments might be better than lower amend ments;with the higher temperature, the stronger soil respiration became, and the faster re lease rate of carbon dioxide was; on the change of daytime and nighttime about carbon diox ide emission, the former was higher than the latter; as far as irrigated water depth was con cerned, a lower release rate of carbon dioxide depends on deeper irrigated water depth. Fur thermore, the comprehensive effect on carbon dioxide and methane emissions from soils un der different biochar amendments and hydrothermal condition also were discussed at last.