Why doesn’t SWAN schedule from actual soil moisture probes?

Soil moisture probes (SMP) are valuable tools to monitor your soil moisture status, however their accuracy can vary and is dependent on many factors. Because of this SWAN does not include SMP data to generate an irrigation schedule.

The factors that may affect the accuracy of your SMP data include:

• Location of the SMP in the field. SMPs provide information about one single point in your farm, which means conditions such as soil type variations, air pockets around the probe, soil impermeable layers or simply SMPs installed far from the root zone, could supply misleading information about the actual soil moisture status.
• Unlike SMP data, SWAN’s model considers how your crop water use is affected when your crop is subjected to stress factors. It then uses this information to generate an accurate irrigation schedule.
• Some probes may not be calibrated to be used in a specific soil type, which could lead to inaccurate soil moisture readings.

Other factors to consider are:

• Not everyone has SMPs in every field.
• Probes cannot give information on future soil moisture status.
• Probes can stop working.