节水灌溉对稻蟹共作多环芳烃降解的驱动机制及其生态调控效应

Driving Mechanism and Ecological Regulation Effect of Water-saving Irrigation on Degradation of Polycyclic Aromatic Hydrocarbons in Rice-Crab Co-cultivation

摘要:

揭示了节水灌溉对稻蟹共作系统多环芳烃（PAHs）降解的驱动机制及其生态调控效应。通过对比常规淹灌（CF）、浅湿灌溉（SWD）与干湿交替灌溉（AWD）模式发现：节水灌溉模式（AWD、SWD）显著提升土壤菲（Phe）降解率至95.36%和82.99%，较CF（66.68%）分别提高43.01%与24.46%。AWD处理在减少稻蟹系统下菲生物积累量更为优异，显著降低水稻根、茎、叶菲积累量35%~55%，蟹体菲富集量较CF下降52.08%，系统性阻断污染物食物链传递风险。此外，节水灌溉（AWD、SWD）有效改善了土壤环境质量。通过重塑土壤团粒结构与土壤氧含量提升多环芳烃好氧降解；通过改善土壤氧化还原酶及水解酶活性能激活多环芳烃代谢分解反应；通过改良土壤营养元素促进土壤微生物群落增殖与结构优化，多因素协同作用共同驱动了稻蟹系统土壤多环芳烃代谢增强。本研究阐明稻蟹共作模式下节水灌溉驱动的菲多界面协同降解机制，可为生态农业污染治理与资源协同优化提供创新范式。

Abstract:

The driving mechanism and ecological regulation effect of water-saving irrigation on the degradation of polycyclic aromatic hydrocarbons (PAHs) in rice-crab co-cultivation system was revealed. By comparing the conventional submerged irrigation (CF), shallow and wet irrigation (SWD) and alternate dry and wet irrigation (AWD) modes, it was found that the degradation efficiency of soil phenanthrene was significantly increased by 95.36% and 82.99% under water-saving irrigation (AWD\\SWD) treatments, which was 43.01% and 24.46% higher than that of CF (66.68%), respectively. AWD treatment was more excellent in reducing the phenanthrene bioaccumulation of rice crab system, significantly reducing the accumulation of PAHs in roots, stems and leaves by 35%~55%, and the enrichment of phenanthrene in crab body was decreased by 52.08% compared with that of CF, systematically blocking the risk of contaminant food chain transmission. Furthermore, water-saving irrigation (AWD\\SWD) effectively enhanced soil environmental quality, which was achieved through reshaping soil aggregate structures and increasing oxygen availability, which promoted aerobic degradation of phenanthrene, activation of PAH metabolic decomposition pathways via improved redox enzymes and hydrolases, enrichment of soil nutrients that stimulated microbial community proliferation and structural optimization. The synergistic interactions of these factors significantly strengthened phenanthrene metabolism in rice-crab system soils. The research result elucidated the multi-interface collaborative degradation mechanism of phenanthrene driven by water-saving irrigation under rice-crab co-cropping mode, and provided an innovative paradigm for pollution control and resource collaborative optimization in ecological agriculture.