Root Growth, Calcite Precipitation, and Gas and Water Movement in Fractures and Macropores: A Review with Field Observations
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Citation:The Ohio Journal of Science. v100, n3-4 (June-September, 2000), 88-93
Recent research on the presence and dynamic nature of fractures and soil macropores has generated interest in their impact on root growth in minimally disturbed soils due to no-till or reduced tillage farming practices. The balance of water, air, and nutrients in the subsurface is, in part, determined by the structure and type of macropores. Biological systems can create and expand the network of biopores, or change the biogeochemistry within a given fracture or biopore. In the field, roots have been observed to grow preferentially through fractures. At a demonstration test pit at The Ohio State University (OSU) Molly Caren Agricultural Research Center in London, OH, networks of roots were exposed within fractures at 1.0 to 2.0 m in depth. A streambank on the OSU Waterman Agricultural and Natural Resources Laboratory in Columbus, OH, provided a natural exposure of fractures and roots preferentially growing in these fractures at depths of 1.0 to 1.5 m. A deeply incised streamcut in Batavia, OH, revealed live roots growing (at a depth of 15 to 20 m) within pre-Illinoian glacial till fractures. Microbial action upon living roots and in the degradation of dead root material can lead to calcite precipitation and infilling of fractures and other macropores. Earthworm burrowing can redistribute nutrients to the deeper subsurface, facilitating root growth at greater depths. During construction of the small test pit located near Tremont City, OH, a live earthworm was observed within a fracture at a depth of approximately 3.0 m.
Author Institution: Department of Horticulture and Crop Science, and Department of Food, Agricultural, and Biological Engineering, The Ohio State University
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