You explanations only add to my confusion- is this how you communicate with your clients- they must believe you are genius! What I understand about irrigation is that farmers monitor the moisture level of their soil primarily by measuring the moisture level of their soil. I've never heard of a Davis sensor and I'm sure most on this forum have not either.
Come on Richard, try a little harder. Pretend you are talking to an 8 year old and explain in easy to understand language how you determine how much water your fruit trees need at any given time during the season, with all the variables in play (including the amount of water actually needed by the trees at any given point in fruit development).
I'm trying to learn something here, and I'm sure others are as well. When I look up university specs on monitoring irrigation needs, what I find doesn't seem to jibe with what you are writing, but then, I'm just a layman.