How Wet is Wet?

How should we measure soil moisture with respect to the needs of our crops? There are many competing technologies for soil moisture sensors, and claims for superiority of a given technology over another. Most growers already have methods for determining how wet their soil is relative to the needs of their crop. A sensor should not replace these methods, but should be used to augment existing knowledge and automate the processing of acquiring information. Any sensor which gives repeatable readings, which can be correlated with existing processes and knowledge, should be useable in an information gathering and automation project. If as a grower, you can examine the soil and note that daily irrigation can be skipped due to enough moisture present, and a sensor can give you a reading that will repeatedly correlate to that moisture level, then that is a useful technology.