The IAS Advanced AutoStart™ can use feedback from soil moisture sensors to automate irrigation in two different ways.  Customers can use the soil moisture level directly by setting the system to start based on a soil moisture level.  With this method, a specific time period can be blocked out, so that irrigation does not happen during the heat of the day, for example.  The second method is to use normal schedule irrigation, but allow the scheduled irrigation to use the soil moisture threshold as a check to not irrigate if soil moisture is high enough.  This is probably the most consistent method.