Macropore and surface seal interactions affecting water infiltration into soil

Using Webster clay loam (Typical Haplaquoll) and Port Byron silt loam (Typical Hapludoll) soils, this study examined the effect of simulated rainfall on water infiltration into soils with earthworm and artificial macropores. Comparison of infiltration rates between bare and covered treatments showed that a surface seal developed on bare soils, which was effective in sealing visible macropores varying in diameter from 2 to 5 mm. Subsequent measurements with a disk permeameter showed that open maropores at the surface were ineffective in conducting water to deeper depths because they lacked continuity below the surface. Likewise, much of the increase in water flux due to earthworm macropores was contributed by only a few of the visible macropores. The description of macropore size and number by themselves may be insufficient for developing models of water entry into soils containing earthworm macropores. -from Authors