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NOTE: To get off this list, send email to majordomo@aqua.ccwr.ac.za with the body of the message containing the line: unsubscribe sowacs [Apologies for cross-posting, but I thought this would be of interest to sowacsers. (I wonder how many members of IRL are not members of sowacs and vice versa?) Bruce] Very interesting paper with capacitance methods versus evaporation rates. We, at the Rural Engineering Department of University of Švora, Portugal, have been using capacitance probes for several years to measure soil moisture content to schedule and evaluate surface and sprinkler irrigation on many crops with good results. We bought different capacitance probes, one of which is the Enviroscan. Unfortunately this last equipment didn't give good results in our soils. We have layered soils, with a first layer with a sandy loam texture, in which the environscans readings are more or less accurate, but within the second layer, which has a high clay content, the environscan readings are not reliable. Maybe it could work well within homogeneous soils, but our experience in layered soils is not good. We tried to calibrate the probe but it was impossible since the equipment didnĄt allow us to change the default calibration parameters. Maybe the new models have being improved and/or other investigators have other opinions. We are still using capacitance based methods which we tested against neutron probe measurements with very good results. Regards Luis Silva ---------------------------------------------------------------------------- -- Luis Leopoldo Silva Universidade de Švora Dep. Engenharia Rural Apartado 94 7002-554 EVORA PORTUGAL Fax: +351-266-711189 telf: +351-266-760800 homepage: http://www.der.uevora.pt/~luis/ ----- Original Message ----- From: Peter Broomhall <hortech@ATS.COM.AU> To: <IRRIGATION-L@LISTSERV.GMD.DE> Sent: Sunday, November 19, 2000 2:34 AM Subject: [IR-L] Comparison - Capacitance vs evaporation rates > Dear Members > > http://ats.com.au/~hortech/comparison.html > > Case study of data from two capacitance sensors (EnviroSCAN and C-Probe) > versus Plant water requirements as calculated from evaporation data. > > Regards > > Peter Broomhall >