Not enough water for established crops.

Satisfactory for young crops or after fertigation when it is important to eliminate leaching. Apply more water to established crops at each irrigation or shorten the interval between two irrigations.

Wetting front has penetrated into the lower part of the root zone.

Much of the time this is the desired result. However during hot weather or when the crop is at a sensitive growth stage irrigation should be increased. The deep detector should respond from time to time, showing that the entire root zone is wet.

The wetting front has moved toward the bottom or below the root zone.

Both detectors should respond when irrigating to satisfy high demand for water. However if this happens on a regular basis, particularly in the case of sprinkler irrigation, over-watering is likely. Reduce irrigation amounts or increase the time interval between irrigations.

Soil or irrigation are not uniform or the soil surface is uneven.

Ensure the soil is level over the detectors and water is not running towards or away from the installation site. Check uniformity of irrigation or location of drippers.