There are many methods for predicting when and how much water plants need, and they all have their strengths and drawbacks.
Our recommendation is to use more than one method. In most of the published studies presented on this website, we compare the response of a Wetting Front Detector against a tensiometer or soil water content monitoring device.
Tensiometers and other instruments that measure soil suction are brilliant at telling you when water needs to be applied, but not always as good at identifying over-irrigation. Capacitance type meters are excellent at showing how different layers of soil are wetting and drying, but for those with less experience, mistakes can be made interpreting the data.
Methods based on weather station data and evaporation pans generally keep irrigation within broad but reasonable limits. However accuracy is dependent of knowing the relationship between crop water use and reference evaporation. If errors occur they become cumulative; there is no feedback unless a crop wilts or gets waterlogged.
The FullStop provides complementary information to the above methods. Suction measuring devices can be used to show how dry the soil is getting, and FullStops to show how much water needs to be applied. A capacitance probe gives excellent detail at one location and FullStops could be spread out at a strategic depth to cover variability. Evaporation figures allow a prediction of reasonable water requirements, but the FullStop can be used to provide feedback to show when the model diverges from reality.
We cannot overemphasize the importance of monitoring the soil solution from the FullStop and evaluating this against the irrigation strategy. Irrigation, salt and nutrient management are completely interlinked. Often knowing how the electrical conductivity or nitrate levels are changing tells you more about water management than studying a whole lot of water content data. For example nitrate levels will drop sharply if over-irrigation occurs. Depending on the quality of the irrigation water, EC levels will gradually rise during periods of under irrigation.