Soil structure development in a five-year chronosequence of maize cropping on two contrasting soil textures

Abstract

The development of soil structure is a complex process driven by the interplay of physical, biological, and chemical factors. Plant roots play an important role in shaping the porous soil architecture; however, their relative contribution is hard to quantify. This study assessed root-driven structural (bio-)pore formation, its impact on hydraulic properties (e.g., infiltration capacity), and how it is influenced by soil texture (loam vs. sand). We combined X-ray computed tomography and machine learning-based segmentation to analyze 720 soil cores from a five-year chronosequence of maize cultivation without tillage. With this methodology, we showed that soil texture was the primary driver of soil structure development and the dynamics of root-derived organic matter. In loam, rapid root decomposition left an interconnected biopore network, enhancing infiltration despite soil settlement. In sand, a greater accumulation of root-derived particulate organic matter resulted from more vigorous root growth, larger diameters, and slower root decomposition. In sand, soil settlement reduced the infiltration capacity over time. These findings underscore the need to integrate organic matter dynamics into soil structure studies, with implications for sustainable land management and carbon storage strategies. Expanding this approach to diverse soils and climates could improve soil process modeling and soil management globally. • Soil texture is a key factor governing soil structure development. • Machine learning segmentation can differentiate living from dead root tissues in 3D X-ray CT images. • Plant roots increase the infiltration capacity of fine-textured soils. • Root necromass accumulates in coarse-textured and carbon-poor soils. • Biopores are prone to collapsing in coarse-textured soils.

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