Whether using reclaimed or potable, overwatering in the landscape is easily preventable

By Bernard Cardenas

Some homeowners with automatic irrigation systems are over-watering their lawns in Florida without even knowing it. To cope with this issue, researchers at UF have been testing different soil moisture sensors, a promising technology that can potentially reduce waste of irrigation water.

Examples of widely available soil moisture sensor devices

Purple Pipes Among Us

In Florida, an important number of homes use reclaimed water to irrigate their landscape. Using soil moisture sensors in this context could present a problem because reclaimed water may contain more salts than potable water, and these salts could alter sensor readings when measuring the soil water content.

Therefore, irrigation specialists evaluated the functionality of four soil moisture sensor brands under both reclaimed and potable water, and quantified their potential irrigation savings. They also analyzed the consistency of each brand to control irrigation and, finally, they compared the brands to see if all of them were effective, or not.

Research Mode

The study was carried out in Gainesville in turfgrass plots irrigated with potable water and reclaimed water (2009 and 2010 respectively). Four soil moisture sensor brands were tested and were compared to a treatment that had no sensor feedback, which is the most common situation in Florida.

All the soil moisture sensors tested applied significantly less water than the comparison treatment (which had no sensor feedback). This was a consequence of the soil moisture sensors not allowing irrigation when soil was wet enough.  

The water savings ranged from 46% to 78% under potable water, and from 45% to 68% under reclaimed water. This means that the tested soil moisture sensors could be used under reclaimed or potable water conditions. Even more promising: these important water savings were obtained during a mostly dry period.

Also important to mention is that these water savings were attained without compromising the turf quality, which always rated good or higher, during the 2 year study.

The Bottom Line

From these results, which are comparable to those achieved in other similar experiments, it is clear that soil moisture sensors can be a useful tool for conserving water on turfgrass irrigated with either potable or reclaimed water.

(Adapted from a recently published research article available here.)