【摘要】 为了阐明外源有机碳对土壤碳库的作用机制,以餐厨垃圾为原料,制备了4种不同分子量级的外源有机碳,通过室内试验,研究了外源有机碳对土壤有机碳组分及土壤团聚体的影响.结果表明:(1)以分子量≤1 ku为主的小分子有机碳处理组土壤中w(DOC)(DOC为水溶性有机碳)比CK组增加了0. 383 g/kg,CO2累积释放量达到(6. 595±0. 259)mg/kg(以C计);微生物活性增强,>5 mm水稳大团聚体质量分数相对于CK组提升了25. 06%,表明小分子有机碳增强了土壤微生物活性,微生物通过菌根网络缠绕作用促进大团聚体形成,增强土壤团聚体稳定性.(2)以分子量≥5 ku的大分子有机碳为主的大分子有机碳处理组w(POC)(POC为颗粒态有机碳)为CK组的5. 65倍,0. 5～1 mm水稳大团聚体质量分数增加了10. 84%,有机碳贡献率提升了14. 79%,表明大分子有机碳通过增加土壤中w(POC),促进0. 5～1 mm水稳大团聚体形成,提高团聚体有机碳贡献率.研究显示,不同分子量级外源有机碳通过不同的方式改善土壤团聚体结构进而促进土壤有机碳固定,餐厨垃圾生物强化有机肥中各量级有机碳比例合理,能够明显提升土壤有机碳水平,增加土壤团聚体稳定性.更多还原

【Abstract】 In order to elucidate the effects of exogenous organic carbon on soil carbon,4 kinds of exogenous organic carbon with different molecular weights were prepared from kitchen waste. The effects of the exogenous organic carbon on soil organic carbon components and soil aggregates were studied through laboratory experiments. The main results are as follows:(1) Compared to the control,the dissolved organic carbon in the soil treated with organic carbon( molecular weight ≤1 ku) was increased by 0. 383 g/kg. The cumulative release of CO2(( 6. 595 ± 0. 259) mg/kg),enhanced microbial activities,and increased water-stabilized macroaggregates( by 25. 06%) were observed comparing with those of the control samples,indicating that small molecular organic carbon might enhance the stability of soil aggregates by increasing the formation of the mycorrhizal network which was resulted from the promoted microbial activity.(2) Compared to the control samples,the organic carbon in the soil treated with macromolecular organic carbon( molecular weight ≥5 ku) was increased by 5. 65 times. Meanwhile,there was about 10. 84% increase in water-stabilized large aggregates( 0. 5-1 mm) and 14. 79% increase in the contribution rate of organic carbon,which indicated that the macromolecular organic carbon could increase the organic carbon content of soil,promote the formation of 0. 5-1 mm large water-stabilized aggregates,and increase the organic carbon contribution rate of aggregates. These results have shown that exogenous organic carbon with different molecular weights improves soil aggregate structure and promotes soil organic carbon fixation in different ways. The treatment of soil with the bio-organic fertilizer with an appropriate organic carbon proportion could significantly improve the soil organic carbon level and the stability of soil aggregates.更多还原