Soil Moisture – ET Demonstration Project

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In the summer of 2006 the Irrigation Water Management Society launched a new educational – demonstration project to help people understand water use in the landscape. The project is now complete and is being posted on this site. We are posting the graphs of the soil moisture in real-time. This project is an educational – demonstration project, not a scientific research project. We wish to show general relationships in an easy to read format for those who are not soil scientists. The purpose is to help people understand what happens underground in the soil when irrigation and rainfall occurs.

We choose a site next to a weather station on our network and installed soil moisture sensors. We are also posting the ET data from a weather station located 25’ away. The idea being that visitors to the site can see what is happening to the soil moisture and then see what is happening in regard to the weather (ET) at the same time.

Proceed to view Soil Moisture data

We then installed a tipping rain bucket sensor in the middle of the plot to measure any irrigation and or rainfall.

We chose a 15’ x 15' area and installed 6 soil moisture sensors 2 each from Campbell Scientific, Dynamax and Irrometer. Each company has two sensors installed, one at 4" and one at 8". The 4" shows what is occurring in the rootzone of the turf and the 8” shows when over watering occurs and water goes below the active rootzone of the turf.

The area is irrigated by four 15’ spray heads (90 degree arc) in each corner. We performed an audit and the DU is 67%. The system is controlled by a conventional irrigation controller with a schedule determined by the IWMS based on historical ET and modified based on ET data from the weather station at hand.

There is one additional sensor that is installed outside of the irrigated area as a control to show the soil moisture in a non-irrigated area (it does receive rainfall).

The weather station is located about 25’ away from this project.

We download the ET data from this station and create a graph that is posted right next to the soils moisture graphs.