Evaluation of porous cup soil-water extractors: Physical factors

The performance and characteristics of small, porous cup, soil-water extractors, installed in a soil with known water-transmission properties, are described. Cup conductivities decreased sharply during an 8 week period and, in the absence of other flux limiting factors, would limit water entry in the permeable topsoil but not in the slowly permeable subsoil. Measured cup water uptake however was much less than that predicted from either cup conductivity or soil water transmission properties. This is attributed to flow impedance near the cup walls. Under these conditions flow distribution in a soil with extractor cups would be much closer to that of an unextracted soil than is predicted from soil water flow theory.

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Measuring Water Transmission Parameters in Vadose Zone Using Ponded Infiltration Techniques

Journal of Agricultural and Marine Sciences [JAMS] ◽

10.24200/jams.vol7iss2pp17-22 ◽

2002 ◽

Vol 7 (2) ◽

pp. 17

Author(s):

D.E. Elrick ◽

W.D. Reynolds

Keyword(s):

Soil Water ◽

Vadose Zone ◽

Plant Nutrient ◽

Industrial Chemicals ◽

Transmission Parameters ◽

Primary Mechanism ◽

Soil Water Flow ◽

Constant Head ◽

Water Transmission ◽

Infiltration Techniques

The flow of soil water is characterized by water transmission parameters, field-saturated hydraulic conductivity, matric flux potential and sorptivity. Soil water flow is, in turn, the primary mechanism by which soil contaminants, such as excess plant nutrient, bacteria, viruses, salts, and industrial chemicals are transported. Consequently, knowledge of soil water transmission parameters is essential for understanding, preventing and remediating the contamination of soil water and ground water. This paper describes steady-state and transient methods for obtaining soil water transmission parameters from ponded infiltration under constant head and falling head conditions in surface rings and shallow auger holes. Also discussed are the conditions under which the various methods are most appropriate.

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Water transmission properties of a sandy-loam soil estimated with Beerkan runs differing by the infiltration time criterion

Journal of Hydrology and Hydromechanics ◽

10.2478/johh-2021-0010 ◽

2021 ◽

Vol 69 (2) ◽

pp. 151-160

Author(s):

Vincenzo Bagarello ◽

Gaetano Caltabellotta ◽

Massimo Iovino

Keyword(s):

Soil Water ◽

Sandy Loam ◽

Water Pressure ◽

Soil Surface ◽

Sandy Loam Soil ◽

Water Volume ◽

Transmission Properties ◽

Time Criterion ◽

Loam Soil ◽

Water Transmission

Abstract The Beerkan method consists of a ponded infiltration experiment from a single ring inserted a small depth into the soil. Fixed, small volumes of water are repeatedly poured into the ring to maintain a quasi-zero head on the soil surface. According to the standard Beerkan infiltration run, a new water volume is poured on the infiltration surface when the previously applied volume has completely infiltrated and the soil surface is entirely exposed to air (ta criterion). However, water could also be applied when the soil exposition to air begins (to criterion) or half the soil surface is exposed to air (tm criterion). The effect of the infiltration time criterion on determination of the water transmission properties of a sandy-loam soil was tested. As compared with the standard ta criterion, the two alternative criteria (to , tm ) yielded higher and/or more variable estimates of soil water transmission properties. The saturated soil hydraulic conductivity, Ks , was the most sensitive property to the infiltration time criterion. However, statistically significant differences for Ks were not practically substantial since they did not exceed a factor of 1.7. Infiltration time effects likely occurred due to differences between ponding depth of water, soil water pressure head gradient, air entrapment and soil mechanical disturbance. The standard ta criterion was suggested for performing a Beerkan experiment in the field since it appears to yield the most reliable estimates of a mean value. However, the to criterion could be considered in dual permeability soils to maintain macropores active. Factors that could appear minor in the context of an experiment can have statistically relevant effects on water transmission properties.

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