We are planning to set this up in a friends, (who is a farmer) soy bean farm. We plan on using a set of capacitive soil moisture sensors to monitor soie moisture In the midwest we use rain as irrigation and plan on throttling downs the water leaving the field if we anticipate a dry few days. We are also looking at (eventually) putting in an propeller anemometer to get data that will help us better prediction of water loss in the field as a function of wind, humidity and temperature. We have a working arduino prototype now and are assembling a probe to get moisture at various depths, Since some of the probes may be miles away, we plan on using a electron unit on each probe.
We plan on publishing this as freeware or at least making it freely available. If we make money from it, it will be by assembling, selling and customizing the equipment. Maybe install it if local.
See this video for what they are doing with purchased water farms in the west. Since we cannot throttle the water coming in from the sky, we can only throttle the water leaving the field