胶结物质驱动的土壤团聚体形成过程与稳定机制

Soil aggregates form the basic units of soil structure, similar to cells in organisms. Soil aggregates control the movement and storage of water, air, heat and nutrients in soils. Binding agents are crucial in the process of soil aggregate formation. However, there is limited information regarding the effects and mechanisms of different binding agents in soil aggregation. In this project, typical soils under different fertilization and land use from Black soil zone in northeastern China and Red soil zone in southern China (both are important agricultural areas in China), and Loess zone in northwestern China (an area with vulnerable ecology) will be sampled. Properties of soil aggregates in these samples will be measured with physical separation and chemical analysis. In this project: (1) Distribution of binding agents and key determining factors in soil aggregates from various climate zones will be clarified. The transformation of binding agents under different fertilization and land use will be detected and their relationship with aggregate stability will be discussed. (2) The effect of binding agents on aggregate formation and the stabilization mechanisms will be studied using molecular environment detection approaches and interfacial electrochemical methods. (3) Self-organization process in soil mineral→organic-mineral complex→ micro-aggregate → macro-aggregate, driven by binding agents will be proposed based on the NICA-Donnan and Struc-C model combining the self-organization principle. This project aims to promote our understanding of aggregate formation and its stabilization mechanism, soil cycling and evolution process, and to provide scientific basis to improve soil quality and productivity.

团聚体是土壤的基本组成单元，控制着土壤水、气、热及养分的保持和运移。胶结物质在团聚体形成过程中起决定性作用，但不同类型胶结物质在土壤团聚体中所起作用与机理仍不清楚。本项目选择对我国粮食生产占重要地位的东北黑土区与南方红壤区、生态脆弱的黄土高原区的代表性土壤为研究对象，采集不同施肥和土地利用条件下的土壤，结合团聚体的物理分组与相关组分的化学形态分析，研究：①不同区域土壤团聚体胶结物质自然的分布规律与主控因素，剖析人为干扰下胶结物质的转化特征；②利用分子环境手段和界面电化学方法，探讨胶结物质在土壤团聚体形成与稳定中的作用机制；③基于NICA-Donnan和Struc-C模型，结合自组织原理，建立胶结物质驱动的“土壤矿物颗粒→有机无机复合体→微团聚体→大团聚体”自组织形成过程模型。为揭示土壤团聚体的形成与稳定机制、物质循环与演化过程、提高土壤质量和生产力等提供科学依据。

本项目以不同类型胶结物质为核心，研究了胶结物质驱动下土壤团聚体的形成过程与机制。取得的主要结果有：（1）明确了人为干扰下红壤团聚体稳定性变化的力学特征，揭示了有机质和碳酸盐对钙质土壤团聚体胶结贡献、稳定性影响的差异与机制。（2）量化了腐殖酸与粘土矿物互作机制，解析了土壤团聚体胶结机理与层级结构特征，定量描述了土壤团聚体的自组织形成过程与临界特征。（3）深入剖析了AM真菌分泌的球囊霉素对水稳性团聚体的稳定机制与贡献比例，并研发了球囊霉素土壤改良剂。（4）利用地统计学和空间预测等分析，实现了快速准确获得土壤团聚体稳定性的空间分布与变异特征，阐明了团聚体形成、转化机制的共性科学问题。.这些成果加深了对土壤团聚体形成与稳定的宏观表现与微观机制的理解，为土壤改良剂的选取与应用提供了重要参考；同时，从空间尺度上进一步揭示了土壤结构退化和演变内因，为良好土壤团聚体的培育提供了策略。.相关成果已在本领域主流期刊发表论文35篇，其中SCI收录26篇，JCR分区一区论文20篇；授权实用新型专利1项、申请国家发明专利2项；先后在国际上受邀作主题报告6次，邀请国外专家7人次；成功申请举办第11届界面与污染国际会议；培养研究生14人。