蒙脱石、高岭石与玄武岩对土壤碳固存的影响

Effects of montmorillonite, kaolinite and basalt on soil carbon sequestration

为了明确玄武岩风化及其风化过程中形成的蒙脱石与高岭石类黏土矿物对土壤碳固存的影响,采用田间微区试验,研究了玄武岩、蒙脱石和高岭石施用下土壤颗粒结构、pH值,及速效养分、可溶性有机碳(DOC)、微生物生物量碳(MBC)、有机碳和无机碳含量的变化。结果表明,与单施山核桃壳有机肥的处理相比,在其基础上配施玄武岩、蒙脱石或高岭石显著(P<0.05)降低了土壤MBC含量,降幅分别为8.7%、10.3%和9.7%;配施玄武岩的处理土壤pH值显著提高0.80,土壤DOC、有机碳、无机碳含量分别显著增加9.4%、3.6%和939.2%;配施蒙脱石处理的土壤交换性钙、镁含量和阳离子交换量分别显著增加77.3%、471.7%、80.2%,土壤有机碳与无机碳含量分别显著增加2.5%和543.2%;配施高岭石处理的土壤水稳性大团聚体(粒径≥0.25 mm)占比显著提升了2.3百分点,土壤有机碳与无机碳含量分别显著增加2.8%和646.3%。此外,除配施玄武岩或蒙脱石的处理显著提升了土壤速效钾含量外,配施3种矿物对土壤其他速效养分(碱解氮、有效磷)含量无显著影响。综上,蒙脱石、高岭石与玄武岩对土壤有机碳有固定作用,玄武岩对土壤无机碳的固定作用最强。施用蒙脱石、高岭石和玄武岩可以实现对土壤有机碳-无机碳的协同固定。

To investigate the impact of basalt,montmorillonite,and kaolinite on soil physicochemical properties and carbon pool components,a field micro-plot experiment was conducted to assess their effects on soil particle structure,pH,and contents of available nutrients,dissolved organic carbon(DOC),microbial biomass carbon(MBC),organic carbon,and inorganic carbon.It was shown that compared to the treatment using pecan shell organic fertilizer alone(H),the treatments of co-application of pecan shell organic fertilizer+basalt(BH),pecan shell organic fertilizer montmorillonite(MH),or pecan shell organic fertilizer+kaolinite(KH)significantly(P<0.05)reduced soil MBC content by 8.7%,10.3%,and 9.7%,respectively.The BH treatment significantly increased soil pH value by 0.80 and elevated soil DOC,organic carbon,and inorganic carbon contents by 9.4%,3.6%,and 939.2%,respectively.The MH treatment significantly boosted the soil exchangeable calcium and magnesium content and cation exchange capacity by 77.3%,471.7%,and 80.2%,respectively,and increased the soil organic carbon and inorganic carbon contents by 2.5%and 543.2%,respectively.The KH treatment significantly enhanced the proportion of water-stable macroaggregates(particle size≥0.25 mm)by 2.3 percentage points,and raised the soil organic carbon and inorganic carbon contents by 2.8%and 646.3%,respectively.Except for the significant rise in available potassium content under BH and MH treatments,BH,MH and KH treatments had no significant impact on the contents of the other available nutrients(alkali-hydrolyzable nitrogen and available phosphorus).In conclusion,applications of basalt,montmorillonite,and kaolinite combined with organic fertilizer could stabilize the soil organic carbon,which achieved the synergistic stabilization of both organic and inorganic carbon,and the application of basalt combined with organic fertilize showed the best effect on the inorganic carbon sequestration.