稻田生态综合种养模式对土壤活性有机碳组分特征的影响

Influence of comprehensive ecological farming model on characteristics of soil active organic carbon components in paddy fields

【目的】通过研究生态综合种养模式下0~40 cm土层活性有机碳组分含量,明确该模式下稻田土壤有机碳组分的敏感性和碳库管理的特征,旨在为研究生态综合种养模式下稻田固碳和养分管理提供理论基础。【方法】以广州市增城区农业生态环境野外工作站3种水稻种植模式[生态综合种养模式(EIM)、水旱轮作模式(RVM)和常规水稻种植模式(CRM)]下的土壤为研究对象,测定土壤总有机碳(TOC)、溶解性有机碳(DOC)、易氧化有机碳(EOC)、颗粒态有机碳(POC)和微生物量碳(MBC),并探索稻田土壤活性有机碳库变化的影响因素。【结果】EIM模式土壤TOC为10.55 g/kg,DOC、EOC、POC和MBC 4种活性有机碳的含量分别为0.29、1.38、2.09和0.11 g/kg,明显高于RVM和CRM模式土壤;土壤微生物熵也以EIM模式最高,与RVP和CRP模式相比,分别提高51.11%~85.72%和46.04~223.99%;3种种植模式0~10 cm土壤有机碳组分以MBC最敏感,而10~20 cm土壤则以EOC最敏感;EIM模式显著提升了土壤各碳库管理指标,其中MBC是土壤碳库管理指数变化的重要有机碳组分因子;冗余分析结果表明,土壤有机碳组分的变化主要受土壤容重和pH的影响。【结论】MBC既是土壤有机碳组分变化的敏感性指标,也是土壤碳库管理指数变化的重要影响因子。生态综合种养模式主要通过影响土壤容重和改变土壤微生物活性,从而提高土壤有机碳库。生态综合种养模式可显著提高土壤有机碳库水平,是水稻土壤固碳的有效种植模式。

[Objective]In order to investigate active organic carbon components in 0-40 cm soil layer under comprehensive ecological farm-ing pattern,the sensitivity of active organic carbon(AOC)and characteristics of carbon pool management were examined to provide a theo-retical basic for carbon sequestration and nutrient management in paddy field under this pattern.[Method]The soils under three farming pat-terns,i.e.,comprehensive ecological farming mode(EIM),rice-vegetable crop rotation mode(RVM),and conventional rice farming mode(CRM)at the Agricultural Ecological Environment Field Station in Zengcheng District,Guangzhou City,were selected to determine total organic carbon(TOC),dissolved organic carbon(DOC),oxidized organic carbon(EOC),and microbial biomass carbon(MBC),and to explore the factors influencing changes in soil active organic carbon components.[Result]In EIM,TOC was 10.55 g/kg,DOC EOC POC and MBC contents were 0.29,1.38,2.09 and 0.11 g/kg,respectively,and those were significantly higher than that of RVM and CRM.Soil microbial entropy was the highest in EIM,and increased by 51.11%-85.72%and 46.04%-223.99%,respectively,com-pared with RVM and CRM.The most sensitive AOC within the O-10 cm layer was MBC,whereas within the 10-20 cm layer,EOC exhibi-ted the highest sensitivity.EIM significantly improved soil carbon pool management indexes,with MBC being an important component factor of soil carbon pool management index.The results of redundancy analysis showed that the variation of soil organic carbon components was mainly affected by soil bulk density and pH.[Conclusion]MBC serves as a sensitive indicator of changes in AOC components and a signifi-cant influencing factor in soil carbon pool management indexes.The comprehensive ecological farming mode enhances soil AOC components mainly by affecting bulk density and microbial activities,significantly elevating soil carbon storage.In conclusion,comprehensive ecological farming mode is an effective practice for carbon sequestration in paddy field.