甘蔗渣和甘蔗渣炭对土壤温室气体排放的影响

在室内模拟水田环境,比较研究水田下添加甘蔗渣及甘蔗渣炭对土壤性质及温室气体排放的影响。结果表明:添加甘蔗渣炭能显著提高土壤有机碳、全氮、速效磷和速效钾的含量,而甘蔗渣只能提高土壤有机碳的含量。甘蔗渣和甘蔗渣炭都能减少N_2O排放,但由于二者对土壤Eh的影响程度差异导致N_2O减排的机制不同,甘蔗渣主要耗氧分解形成强还原不利于N_2O的产生,而甘蔗渣炭则通过增加通气性使土壤处于适宜于硝化发生的环境降低N_2O的排放。由于甘蔗渣和甘蔗渣炭都不能使土壤处于适宜CH_4产生的氧化还原电位(Eh)环境而没有导致CH_4排放。甘蔗渣和甘蔗渣炭的综合温室效应没有差异,但都显著低于CK。甘蔗渣转化成甘蔗渣炭后应用,既能改善土壤又能减排温室气体排放。

Effects of Bagasse and Its Biochar on the Greenhouse Gas Emissions of Paddy Soil under Waterlogged Condition in Hainan Province

An indoor experiment was conducted to investigate the effects of bagasse and its biochar on greenhouse gas emissions from the paddy soil under 30 ℃ and waterlogged conditions.Three treatments were arranged:bagasse,biochar from bagasse and control (CK).The results showed that the bagasse-based biochar significantly increased contents of organic carbon,total N,available P and K,whereas bagasse significantly increased soil organic carbon content.Both biochar and bagasse mitigated N2O emissions but were different in the mechanism of N2O emission mitigation due to the difference in the effect of bagasse and its biochar on soil redox potential (Eh).The bagasse consumed mainly oxygen to form a strong reduction in the soil,which was not conducive to the production of N2O,while the bagasse-based biochar mitigated the emission of N2O through soil aeration suitable for nitrification.Both bagasse and bagasse-based biochar did not create a soil Eh environment suitable for CH4 emission and had no change in CH4 emissions.There was no significant difference in overall greenhouse effect between bagasse and its biochar,but they had significantly lower greenhouse effect than CK.It was recommended to convert bagasse into biochar for application in the paddy field.Bagasse-based biochar can not only improve the soil but also mitigate the emissions of greenhouse gases.