土壤钙的形态特征、生物地球化学循环及其固碳调控机制OA

Calcium(Ca)is abundant in soils and performs multiple ecological functions beyond its role as an es-sential plant nutrient.However,the different forms of soil Ca,the biogeochemical cycling of Ca,and the role of Ca in regulating soil organic carbon sequestration remain poorly understood.This article reviews the species and sources of soil Ca and examines how they affect SOC stabilization through abiotic pathways such as cation bridg-ing,aggregate cementation,Ca-Fe-organic carbon(Ca-Fe-OC)ternary complex formation,and carbonate adsorp-tion and precipitation.Biotic pathways include effects on plant growth,carbon inputs,and shifts in microbial com-munity composition and metabolism.Further,we compared extraction methods for different soil Ca pools,includ-ing water-soluble,exchangeable,carbonate-associated,mineral-bound,and organically complexed Ca,to clarify their applicability and limitations.The key areas for future study include mapping the global distribution of soil Ca species,understanding the roles of exchangeable Ca and CaCO3 in soil aggregation,exploring the combined effects of Ca,Fe,and Al on carbon stabilization,and clarifying the dual roles of Ca in soil organic matter decom-position and stabilization.