Comparing Turfgrass Irrigation Scheduling Based On Soil Moisture Sensors and ET-Controllers.

In the southwestern U.S. municipalities are proposing the adoption of technologies to reduce the use of fresh water for landscape irrigation. A two year laboratory and field study is currently underway at New Mexico State University to compare water consumption of ‘Advantage' tall fescue and ‘Princess 77' bermudagrass irrigated based on 1) soil moisture readings [Toro® XTRA SMART™ Precision™ Soil Sensor (PSS)], 2) ET monitoring [Irritrol® Climate Logic^TM (CL)], 3) historic ET, and 4) constant run time (C). Turf quality was assessed bi-weekly and soil moisture content was recorded daily. Root architecture was assessed at the end of each growing season. A laboratory study was conducted to investigate the accuracy of PSS under saline soil conditions (0.6, 2, 4 and 6 dS m^-1). In 2012, each treatment resulted in turfgrass quality greater than the minimum acceptable limit. Irrigation schedules based on PSS resulted in lower turf quality in tall fescue plots compared to control plots in September and December. There was no difference in turf quality between any of the treatments for bermudagrass. Root distribution did not differ between treatments for either tall fescue or bermudagrass at any depth. Plots irrigated with a constant run time exhibited highest moisture content, whereas lowest levels were measured on CL- scheduled plots. Irrigation water use was 61% (tall fescue) and 46% (bermudagrass) lower on PSS- scheduled plots compared to plots irrigated with a constant run time.