为明确腐熟稻草、直还稻草与稻草生物质炭3种不同的稻草还田方式对滨海盐渍型水稻土中碳组分的影响，采用为期270 d的室内恒温培养试验，研究了施用等碳量的腐熟稻草、直还稻草(指稻草直接还田)与稻草生物质炭对水稻土有机碳累积及其氧化稳定性、土壤水溶性有机碳和微生物生物量碳含量的影响。稻草生物质炭处理显著提高了土壤有机碳累积量及其氧化稳定性，并增加了土壤微生物生物量碳含量，但对水稻土水溶性有机碳含量并无影响。腐熟稻草与直还稻草处理皆可在短时间内提高土壤水溶性有机碳及微生物生物量碳含量，但对土壤碳累积影响较小，腐熟稻草处理甚至会降低土壤抗氧化能力。稻草生物质炭的施用会增加土壤碳的积累，但若长期施用会降低土壤碳库活性，其可与腐熟稻草或直还稻草配施来减少这一问题。

In order to clarify the effects of three different rice straw returning modes (rotted rice straw, direct return of rice straw, rice straw-derived biochar) on organic carbon activity in the coastal saline paddy soil, an indoor incubation experiment (at 25℃ and 270 days) was designed and conducted to study the potential effect of their equivalent carbon application on accumulation and stability of soil organic carbon, the contents of microbial biomass carbon and dissolved organic carbon. Results showed that application of rice straw-derived biochar increased significantly the accumulation and stability of soil organic carbon, and improved the content of microbial biomass carbon. However, it had no effect on the content of dissolved organic carbon. The rotted rice straw and direct return of rice straw treatments increased significantly the contents of soil dissolved organic carbon and microbial biomass at the beginning of incubation experiment, while they had no effects on the accumulation of carbon. Application of rotted rice straw decreased the stability of organic carbon. In conclusion, application of rice straw-derived biochar could increase the accumulation of organic carbon in soil, but it might also decrease activity of soil organic matter after a long-term application without any application of other organic materials. However, its application combined application with rotted rice straw or direct return of rice straw can reduce this negative effect.

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公益性行业(农业)科研专项项目(201503118-10)资助。