The hot topic of irrigation in the Delta along with the concurrent issue of the declining water level in the Delta alluvial aquifer brings many irrigation and water conservation subjects to the forefront.

One such subject is how to schedule irrigation so that the least amount of water is used to gain the most crop benefit.

I realize that we have entered the realm of using sophisticated models and soil sensors to do this.  However, there may be opportunity to do the same job with simpler devices and tools.

There is a school of thought that pan evaporation may be the simplest approach to estimating just how much water has been used by a crop since the last rain or irrigation.  However, pan evaporation devices are generally located at weather stations that are too distant from an individual field site to provide accurate information for that site.

There is a device developed by the University of Georgia that may overcome this.  It is called the UGA EASY Pan Irrigation Scheduler, and may be a tool worth considering for irrigation scheduling on individual fields in the Delta.

I have neither personally used this device nor can I vouch for its utility for Delta irrigators.  However, Drs. Steve Thomson and Ken Fisher at the USDA-ARS facility at Stoneville have evaluated it and published an article with their findings.  Basically, they found that the device can be calibrated and adjusted in-season to more effectively schedule irrigation.

Again, I am not in a position to endorse the value of this device for irrigation scheduling.  However, it may be worth trying by those producers who want to move beyond the subjective method of field manager recommendations for irrigation without assistance from scheduling aids.

Composed by Larry G. Heatherly, Aug. 2013, larryheatherly@bellsouth.net