The enhanced weathering technology of basalt can promote the fixation of atmospheric carbon dioxide in the form of carbonates/bicarbonates in soils. Earthworms can promote mineral weathering, further contributing to carbon fixation. In this study, we selected red and yellow-brown soil as research subjects and set up three treatments [i.e., control (CK), adding basalt powder (B), and adding basalt powder and inoculating earthworms simu-ltaneously (BE)], and explored the impact and potential mechanisms of earthworm-mediated basalt weathering on Amaranthus tricolor growth, soil respiration, microbial abundance, Ca2 and Mg2+, soil total organic C, inorganic C and mineral-bound organic C in the field. The results showed that B and BE treatments significantly increased soil pH and Mg2+ content of both soils, but significantly increased Ca2+ content, soil respiration, aboveground and belowground biomass of A. tricolor only in the red soil. B and BE treatments significantly reduced reactive Fe and Al minerals in both soils and NH4+-N content of the yellow-brown soil, but did not affect NO3--N content of both soils. BE treatment significantly increased bacterial abundance of the red soil, but did not affect fungal abundance of both soils. BE treatment significantly increased inorganic C content only in the yellow-brown soil, but significantly reduced Fe/Al bound organic C of the yellow-brown soil, and had no significant effect on total C and organic C of both soils. In addition, BE treatment had no significant effect on soil organic C, inorganic C and Fe/Al bound organic C of both soils compared with B treatment. The random forest model analysis revealed that fungal abundance is the key factor regulating organic carbon accumulation in red soils, while active aluminum minerals and iron-aluminum minerals are respectively identified as the critical determinants controlling the accumulation of organic carbon and iron-aluminum bound organic carbon in yellow-brown soils. Our results indicate that adding basalt powder to soil can significantly promote plant growth in the short term, but did not affect soil organic C formation. The role of earthworms in promoting basalt weathering and soil organic C sequestration in the short term is limited.
玄武岩增强风化技术可促进大气中的二氧化碳以碳酸盐或碳酸氢盐的形式固定在土壤中,蚯蚓会促进矿物的风化,进一步促进土壤有机碳的固定。本研究选择红壤和黄棕壤为对象,分别设置对照(CK)、添加玄武岩粉(B)、添加玄武岩粉并接种蚯蚓(BE)3个处理,在田间条件下,探究蚯蚓调控玄武岩风化对苋菜生长、土壤呼吸、微生物丰度、钙镁阳离子、土壤有机碳、无机碳和矿物结合有机碳的影响及潜在机制。结果表明: 与CK相比,B和BE处理显著提高了两种土壤的pH和镁离子含量,但仅显著提高了红壤的钙离子含量、土壤呼吸和苋菜的地上、地下生物量;B和BE处理显著降低了两种土壤的活性铁铝矿物含量和黄棕壤的铵态氮含量,但是对两种土壤的硝态氮含量没有显著影响;BE处理显著增加了红壤的细菌丰度,但对两种土壤的真菌丰度没有影响;BE处理显著增加了黄棕壤的无机碳含量,但是显著降低了黄棕壤铁铝结合有机碳含量,对两种土壤总碳和有机碳含量没有显著影响。此外,与B处理相比,BE处理对两种土壤的有机碳、无机碳和铁铝矿物结合有机碳含量均没有显著影响。随机森林模型分析表明,真菌丰度是调控红壤有机碳积累的关键因子,活性铝矿物和铁铝矿物分别是调控黄棕壤有机碳和铁铝结合有机碳积累的关键因子。综上,向土壤中添加玄武岩粉短期内可以显著促进植物生长,但是对土壤有机碳的促进效果不显著,且蚯蚓在短期内对玄武岩风化及土壤有机碳固存的促进作用也较为有限。.
Keywords: Fe and Al oxides; basalt; earthworm; soil organic carbon; weathering.