proudly sponsored by
|
archiving of SOWACS proudly sponsored by |
|
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 Dear Tom: The matric potential measured by Watermark and volumetric water content measured by D2K are linked by so-called water release curve and it is soil type dependent. However, you might find a curve that mateches the soil type you are working on. There are lots of this kind of work being published. Jason Sun Ph.D. Research Scientist ESI Environmental Sensors Inc. 100-4243 Glanford Ave. Victoria, BC, Canada Tel: 250-479-6588 Fax: 250-479-1412 ----- Original Message ----- From: <owner-sowacs@aqua.ccwr.ac.za> Sent: April 3, 2000 11:59 AM Subject: Volumetric vs Gravimetric > 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 > > I have done some moisture monitoring with Watermarks in the past and now > have use of a Diviner 2000 from Sentek. I wish to be able to compare > previous years data to current data. One problem I see off the bat is that > the Watermarks read in centibars while the D2K reads in mm of water in a > profile. I am curious how I might easily convert between the two without > doing some gravimetric testing to establish the soil true capacity. Even > then, without testing through many matric potentials to establish a proper > curve, how could I be sure that each unit was responding to soil moisture > in a similar fashion?? > Tom Thomson Northwest Agricultural Consulting > 1275 Oak Villa Road tomt@teleport.com > Dallas, Oregon 97338 Phone/FAX 503-623-0468 > > "The only difference between a problem and a solution is that > everyone understands the solution." Charles Kettering > > [Why not compare the two sensors directly in a test bed and allow it to dry > across the range? Bruce]