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 Skewes, Mark (PIRSA) writes: ===8<============== Ken, My summary is that there are minimal differences in terms of accuracy in most of the commercially available soil water monitoring devices on the market, certainly the differences are not significant for irrigation scheduling (the differences may be significant in the context of research work). The Gopher and Diviner are both Capacitance sensors, and in my opinion there is no difference in accuracy, as long as the access tube installation is carried out correctly (always the major issue with Capacitance). I would rate the robustness of the Gopher and Diviner as similar, but I have little field experience with Gopher. The major difference is in terms of cost effectiveness. The Gopher is a little over half the up front cost of the Diviner. However, there is a difference in the data collection process, whereby the Gopher must be held at each depth at which a reading is required, whilst the Diviner uses "Swipe and Go" technology, which just means that the operator simply inserts the wand at a steady rate into the access tube, and the readings are taken automatically at 10cm intervals. The bottom line is that the Diviner is quicker to use, giving savings in operating costs, which will quite quickly add up to cover the difference in up front cost. This factor of the cost of labour is often overlooked in comparing different scheduling tools. Those are my thoughts, but I am happy to be corrected on any points where I may be lacking. Regards to the list members, Mark Skewes Senior Water Management Consultant Irrigated Crop Management Service Primary Industries and Resources SA PO Box 411, LOXTON, SA, 5333 Phone 08 8595 9149 Fax 08 8595 9180 Mob 0408 800 681 E-mail skewes.mark@saugov.sa.gov.au -----Original Message----- From: owner-sowacs@aqua.ccwr.ac.za [mailto:owner-sowacs@aqua.ccwr.ac.za] Sent: Thursday, 14 March 2002 16:58 Subject: Soil moisture measuring equipment Ken Flower writes: ===8<============== We are about to purchase some equipment for measuring soil moisture. This is for irrigation scheduling. The options that I am considering are the Gopher (dielectric constant)and the Diviner 2000 (capacitance). If possible, I would like an/some opinions on which is the most accurate, robust and cost effective of the options. ===8<=========== [Bruce comments Ken I have left your email address off so that all replies come back through this forum. Anonymous comments will be posted, but preferably be bold enough to put your name under comments! Bruce] ===8<===========