1 The James Hutton Institute, Invergowrie, Dundee, DD2 5DA, United Kingdom
2 The James Hutton Institute, Invergowrie, Dundee, DD2 5DA, United Kingdom/Institute of Biological and Environmental Sciences, University of Aberdeen, Cruickshank Building, St Machar Drive, Aberdeen, AB24 3UU, United Kingdom.
We developed an automated miniature constant-head tension infiltrometer that measures very small infiltration rates at millimetre resolution with minimal demands on the operator. The infiltrometer is made of 2.9 mm internal radius glass tube, with an integrated bubbling tower to maintain constant negative head and a porous mesh tip to avoid air-entry. In the bubbling tower, bubble formation and release changes the electrical resistance between two electrodes at the air-inlet. Tests were conducted on repacked sieved sands, sandy loam soil and clay loam soil, packed to a soil bulk density ρd of 1200 kg m-3 or 1400 kg m-3 and tested either air-dried or at a water potential ψ of -50 kPa. The change in water volume in the infiltrometer had a linear relationship with the number of bubbles, allowing bubble rate to be converted to infiltration rate. Sorptivity measured with the infiltrometer was similar between replicates and showed expected differences from soil texture and ρd, varying from 0.15 ± 0.01 (s.e.) mm s-1/2 for 1400 kg m-3 clay loam at ψ = -50 kPa to 0.65 ± 0.06 mm s-1/2 for 1200 kg m-3 air dry sandy loam soil. An array of infiltrometers is currently being developed so many measurements can be taken simultaneously.
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Arriaga F.J. Kornecki T.S. Balkcom K.S. Raper R.L. 2010. A method for automating data collection from a double-ring infiltrometer under falling head conditions. Soil Use Manage. 26 61-67.
Bachmann J. Goebel M.O. Woche S.K. 2013. Small-scale contact angle mapping on undisturbed soil surfaces. J. Hydrol. Hydromech. 61 3-8.
Bowker M.A. Eldridge D.J. Val J. Soliveres S. 2013. Hydrology in a patterned landscape is co-engineered by soildisturbing animals and biological crusts. Soil Bio. Biochem. 61 14-22.
Casey F.X.M. Derby N.E. 2002. Improved design for an automated tension infiltrometer. Soil Sci. Soc. Am. J. 66 64-67.
Castiglione P. Shouse P.J. Mohanty B. Hudson D. van Genuchten M.T. 2005. Improved tension infiltrometer for measuring low fluid flow rates in unsaturated fractured rock. Vadose Zone J. 4 885-890.
Doerr S.H. Ferreira A.J.D. Walsh R.P.D. Shakesby R.A. Leighton-Boyce G. Coelho C.O.A. 2003. Soil water repellency as a potential parameter in rainfall-runoff modelling: experimental evidence at point to catchment scales from Portugal. Hydrol. Process. 17 363-377.
Hallett P. Young I. 1999. Changes to water repellence of soil aggregates caused by substrate-induced microbial activity. Eur. J. Soil Sci. 50 35-40.
Hallett P. Gordon D. Bengough A. 2003. Plant influence on rhizosphere hydraulic properties: direct measurements using a miniaturized infiltrometer. New Phytol. 157 597-603.
Hallett P. Nunan N. Douglas J. Young I. 2004. Millimeterscale spatial variability in soil water sorptivity: Scale surface elevation and subcritical repellency effects. Soil Sci. Soc. Am. J. 68 352-358.
Hallett P.D. Karim K.H. Bengough A.G. Otten W. 2013. Biophysics of the vadose zone: from reality to model systems and back again. Vadose Zone J. 12 4 doi:10.2136/vzj2013.05.0090.
Johnson D.O. Arriaga F.J. Lowery B. 2005. Automation of a falling head permeameter for rapid determination of hydraulic conductivity of multiple samples. Soil Sci. Soc. Am. J. 69 828-833.
Leeds-Harrison P.B. Youngs E.G. Uddin B. 1994. A device for determining the sorptivity of soil aggregates. Eur. J. Soil Sci. 45 269-272.
Lichner L. Capuliak J. Zhukova N. Holko L. Czachor H. Kollár J. 2013. Pines influence hydrophysical parameters and water flow in a sandy soil. Biologia 68 1104-1108.
Logsdon S.D. Jaynes D.B. 1996. Spatial variability of hydraulic conductivity in a cultivated field at different times. Soil Sci. Soc. Am. J. 60 703-709.
Madsen M.D. Chandler D.G. 2007. Automation and use of mini disk infiltrometers. Soil Sci. Soc. Am. J. 71 1469-1472.
Milla K. Kish S. 2006. A low-cost microprocessor and infrared sensor system for automating water infiltration measurements. Comput. Electron. Agr. 53 122-129.
Moret D. Lopez M.V. Arrue J.L. 2004. TDR application for automated water level measurement from Mariotte reservoirs in tension disc infiltrometers. J. Hydrol. 297 229-235.
Moret-Fernandez D. Gonzalez C. Lampurlanes J. Vicente J. 2012. An automated disc infiltrometer for infiltration rate measurements using a microflowmeter. Hydrol. Process. 26 240-245.
Or D. Tuller M. 1999. Liquid retention and interfacial area in variably saturated porous media: Upscaling from single-pore to sample-scale model. Water Resour. Res. 35 3591-3605.
Pittman D.D. Kohnke H. 1942. An automatic self recording infiltrometer. Soil Sci. 53 429-434.
Prieksat M.A. Ankeny M.D. Kaspar T.C. 1992. Design for an automated self-regulating single-ring infiltrometer. Soil Sci. Soc. Am. J. 56 1409-1411.
Spongrova K. Kechavarzi C. Dresser M. Matula S. Godwin R.J. 2009. Development of an automated tension infiltrometer for field use. Vadose Zone J. 8 810-817.
Thompson J.A. Bell J.C. Zanner C.W. 1998. Hydrology and hydric soil extent within a mollisol catena in southeastern Minnesota. Soil Sci. Soc. Am. J. 62 1126-1133.
Wooding R.A. 1968. Steady infiltration from a shallow circular pond. Water Resour. Res. 4 1259-1273.
Zhao Y. Peth S. Hallett P. Wang X. Giese M. Gao Y. Horn R. 2011. Factors controlling the spatial patterns of soil moisture in a grazed semi-arid steppe investigated by multivariate geostatistics. Ecohydrol. 4 36-48.