干湿交替下土壤团聚体稳定性研究进展与展望

Soil Aggregates as Affected by Wetting-Drying Cycle: A Review

团聚体是土壤结构的基本单元,对土壤系统功能(如结构稳定和肥力保持等))至关重要。而干湿交替是导致土壤团聚体演变的重要环境因子,显著影响团聚体稳定性。本文回顾了70多年来干湿交替对土壤团聚体稳定性影响的研究历程,总结了干湿交替条件下土壤团聚体粒径分布和水稳性的变化特征,着重阐述了干湿交替对团聚体稳定性的影响机制,以及影响干湿交替条件下团聚体稳定性的主要因素,并比较分析了近80年来土壤团聚体稳定性研究的主要方法。通过梳理发现,尽管目前报道了大量有关干湿交替对不同类型土壤团聚体稳定性的影响,但是相关研究多集中在单一的土壤系统中,鲜有从复合生态系统的角度探索干湿交替复合作用过程与多重影响机制。同时,由于不同研究所采用的方法差异较大,导致其结果往往可比性较差。由此,本文提出了该领域今后潜在的研究方向:(1)敏感脆弱区干湿交替下土壤团聚体形成和演变机制;(2)干湿交替对土壤团聚体中化学污染物迁移转化的影响;(3)新技术,如电子计算机断层扫描技术(computed tomography,CT))等在团聚体研究中的应用;(4)植物群落与土壤团聚体周转交互作用过程与机理等。

Aggregates, as the basic unit of soil structure, play a fundamental role in ecosystem function such as soil stability and fertility. Wetting-drying cycle is the most common environmental factor affecting the properties of soil aggregates, particularly soil aggregate stability. This paper reviewed the research advances in soil aggregates affected by wetting-drying cycle over the past 70 years, and summarized the characteristics of soil aggregate size distribution, dynamics of water stability, influential factors and their function mechanisms. In addition, this review compared the different methods in measuring soil aggregate stability in the last 80 years. Although different soil types were investigated by studies focusing on soil aggregates affected by wetting-drying cycle, most of the studies were conducted focusing on soil system individually and few on influential mechanisms across ecosystems. In addition, because of the difference between study methods, the obtained results are diverse and lacking of comparability. This review also proposed several perspectives in future studies： 1） dynamics of soil aggregate distribution and formation affected by wetting-drying cycle in fragile ecological zones; 2） the influences of wetting-drying cycle on migration and transformation of heavy metals and toxic chemicals during the turnover of soil aggregates; 3） the application of computed tomography（CT） in studying soil aggregates; 4） the interaction between plant community and soil aggregates.