ISSN: 0041-3216

ISSN: 0041-3216 (Online), 0041-3216 (Print)
Volume 67 Number 1
Research Papers
Measuring soil hydraulic properties after clearing of tropical rain forest in a Costa Rican soil
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The crust test and a desorption method using undisturbed samples placed in porpous cups were applied to measure hydraulic conductivity (K) and moisture retention data of a Humoxic Tropohumult. The crust test measures infiltration rates through a series of man-made crusts with different resistances and subcrust pressure heads. Each rate corresponds to a K value at unit hydraulic gradient. Crusts are applied on top of an undisturbed colour of soil carved out in situ and covered with mortar, allowing use of the method in stony soil. Multiple measurements in forest and in three-year-old pasture indicated a very strong decrease of K-sat from 1000 cm day-1 to 50 cm day-1, respectively. Totally porosities were not different but the forest topsoil contained more continuous macropores in the form of compound packing voids while the pasture soil contained less continuous accommodated planar voids.
Keywords: Crust test; Hydraulic properties; Tropical rain forest; Costa Rica