in-field sensors & monitoring
How to read a sensor graph
Learn to read a soil moisture sensor chart in 3 minutes
BOTTOM OUTIf no irrigation takes place, the stair steps become so shallow that the curve flattens or “bottoms out,” indicating that the plant has used all available water at that depth
STEEP INCLINEShallow sensors typically show a steep incline at the start of an irrigation. This shows the moisture level changing very quickly from low to high.
DRAINAGESmooth drops typically indicate that moisture is draining. Check the sensor below, it probably shows moisture increasing.
STAIR STEP - DEEPStair step drops show daily plant use, i.e. root pull. You can see the plant “drinking!” Deep steps mean high plant use - plentiful water and/or hot days
STAIR STEP - SHALLOWShallow steps mean low plant use - little water and/or cool days
IRRIGATION PEAKShallow sensors typically show a sharp peak at the start of an irrigation. This shows that the irrigation system is shut off and the soil is draining.
INFILTRATION DELAYShallow sensors show immediate moisture increases at the start of an irrigation. Deeper sensors take longer to show moisture increases due to the time it takes for the water to infiltrate.
IRRIGATION PLATEAUIf the irrigation system is left on after the shallow sensors have reached saturation, instead of a peak, you’ll see a plateau.
LITTLE-NO CHANGEPeriods where the line is flat show that there’s little-to-no change in the moisture level at that depth. Irrigations aren’t reaching that depth, and roots aren’t pulling from that depth.
IRRIGATION EVENT BOXThe line that makes box-like shapes at the bottom is from the pressure switch. Each box marks when the irrigation system was running so you can track the times and system pressures for each irrigation event.
This chart includes data from three soil moisture sensors, at 12”, 24” and 36”. Each sensor is represented by a different colored line so you can clearly see the moisture changes at each depth. At the bottom of the chart is the reading from the pressure switch, telling you when your irrigation system has run.