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Water Infiltration and Redistribution in a Silt Loam Subsoil with Vertical Worm Channels
Author(s) -
Bouma J.,
Belmans C. F. M.,
Dekker L. W.
Publication year - 1982
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1982.03615995004600050006x
Subject(s) - macropore , infiltrometer , infiltration (hvac) , loam , ponding , soil science , saturation (graph theory) , soil water , hydrology (agriculture) , geology , hydraulic conductivity , chemistry , materials science , geotechnical engineering , drainage , composite material , catalysis , mesoporous material , ecology , biochemistry , mathematics , combinatorics , biology
Infiltration and redistribution of water in a fine silty, mixed, mesic Fluventic Eutrochrept with macropores (dominantly vertical worm channels) were studied with physical and morphological techniques. Infiltration rates in individual worm channels were measured and channel morphology was studied by excavation after adding methylene blue and gypsum. Three different steady infiltration rates corresponded with different channel morphology. One channel occurred per 200 cm 2 of soil. The measured, dominant infiltration rate in a channel was used to calculate ponding time on and the associated water movement in the soil matrix after adding 2 cm of water. The latter was calculated with an existing simulation model for one‐dimensional infiltration in homogeneous soil using K‐θ and h ‐θ data. Calculations of h indicated lack of soil saturation. This agreed only with in‐situ measurements when small tensiometer cups were used. Large cups intercepted water‐conducting macropores, erroneously suggesting saturation of the entire soil matrix. Addition of a 5‐cm thick layer of sand to the surface of infiltration made the macropores discontinuous and induced saturated conditions, as measured and simulated. Measurement of infiltration rates into individual macropores, rather than calculation of those rates, is recommended when macropore morphology is irregular.