Geographic variations of pore structure of clayey soils along a climatic gradient

• Published in: Catena (Giessen) 2023-03, Vol.222, p.106861, Article 106861
• Main Authors: Wu, Xinliang, Yuan, Zaijian, Li, Dingqiang, Zhou, Jinxing, Liu, Tong
• Format: Article
• Language: English
• Subjects: Pedogenic process; Pore size distribution; Pore structure; Soil structure
• ISSN: 0341-8162; 1872-6887
• DOI: 10.1016/j.catena.2022.106861

Soil pore structure over a wide range of pore sizes regulates soil functions and relies heavily on pedogenic processes. To date, limited knowledge is available on the spatial variations of soil pore structure and underlying mechanisms over a broad geographic scale. Herein, seven typical zonal soils with increased status of soil development in heavy-textures were collected at different genetic horizons under forests along the mid-temperate to tropic climate gradient in eastern China. Pore size distribution (PSD, 0.006 ∼ 800 μm) of aggregates (sized ∼ 1 cm3) and other pore structure characteristics (void ratio, pore area and average diameter) were determined by mercury intrusion porosimetry. Differential PSD displayed tri- or bi-modal patterns and different pore size classes followed diverse geographic trends. Textural pores most influenced by soil type exhibited larger void ratio and pore area in highly than in moderately developed soils; structural porosity most influenced by soil horizon overall decreased with increased soil depth, indicating the decreased levels of hierarchical aggregation whatever soil type. Relative to soil texture and total organic matter (0.70≤|r|≤0.92), total and textural pores were more related to inorganic cementing agents (0.71≤|r|≤0.95, p