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Ian Woodhead writes: Peter Broomhall writes: >Does the Aqauflex have the capability to distinguish spatial >variation in the SMD along the ribbon length? ............. Thank you Peter (Broomhall) for your considered questions and comments. As it is currently configured, Aquaflex provides a mean moisture content integrated along the length of the 3 metre cable, but does not provide an indication of the variability. As you have pointed out, multiple point measurements would provide further information on the moisture distribution, and that a 3 metre long sensor may be non-representative of large scale variations in moisture content. However in most instances, a 3 metre long sensor will frequently give a significantly more reliable indication than one or two point measurements. The question of whether the mean moisture content is as practically useful as a full knowledge of the distribution will be moot in many instances. In the example you cite, irrigation to suit the ponded area would probably adversely deplete the adjacent area and vice versa, so only spatially programmable irrigation with a very high spatial resolution would resolve this issue. Until that becomes common, we will continue to follow solutions which are pragmatic in terms of what can be implemeted as a result of the measurements which are made. Hence our advice is to just collect sufficient data on which to make intelligent water management decisions. In summary, Aquaflex provides a reading of soil moisture content that is integrated over the zone around the sensing cable (as a consequence of its approximately linear response). Aquaflex's advantages include a reduction of the impact of smaller scale soil moisture variations on irrigation management - large scale variations require other management tools. Ian Woodhead Lincoln Technology Lincoln University New Zealand Ph +064 3 3253721 FAX +064 3 3253725 EMAIL woodhead@lincoln.ac.nz WWW http://www.lvl.co.nz/dielectric.htm