Q & A WITH DR . GRADY MILLER

I am looking at ways to better manage irrigation on our baseball field . We hand water the clay , but I want to refine how we schedule irrigation for the turf area . What are some of our options ?

This is a great question with lots of options for you to consider . I will only have space to scratch the surface , so you will probably want to consult with irrigation vendors and equipment experts to get more specific information and pricing on some of the options I will mention .

There are three major components to irrigation management — monitoring , irrigation control , and water delivery . These three components can also be further broken down . For example , monitoring may be evaluating turfgrass stress indicators , soil moisture levels , and / or weather conditions . Turfgrass stress indicators will often show up in response to soil drying , and provide a visual queue that the turfgrass needs to be irrigated . The indicator will be wilting turfgrass , commonly seen as folded or curled leaves or a bluish-green-color turf . There are often specific locations on each field that show early signs of moisture stress . These areas can be used as indicators that the larger area of the field needs to be irrigated . Research is currently evaluating cameras and sensors to detect stress before it is visible , but this technology is mostly experimental . So , at this point , it is not useful for automation of scheduling irrigation .

Soil moisture monitoring may be accomplished using static , in-ground soil moisture sensors or by using portable sensors . The in-ground sensors may be linked back to your irrigation system controller for automation , and most can be monitored remotely with a smart phone . The most common portable soil moisture sensors use TDR ( time domain reflectometry ) for quick and accurate measurements with minimal soil disturbance . They are a bit expensive , but for site-specific monitoring they are hard to beat . Some portable instruments have the option to collect geo-referenced data to allow mapping and monitoring over time .

Weather condition monitoring may be used for shortterm irrigation adjustment or for predictive modeling of water needs . Many of today ’ s irrigation controllers employ weather-monitoring devices and scaled-down

prediction models to automatically adjust irrigation controller runtimes based on current weather conditions and plant water demands . These are known as ET ( evapotranspiration ) controllers .

An irrigation controller that can use information from a soil or weather sensor , and automatically make adjustments , is known as a “ smart controller .” All irrigation manufacturers have some type of smart irrigation technology in their product line . The newest systems designed around smart technology offer amazing control and monitoring , but older controllers can often be retrofitted to take advantage of sensor technology . Vendors will usually provide the expertise to set up their systems to maximize functionality .

Water delivery is the application rate and distribution uniformity of the water by your irrigation system . These two values are normally measured with an irrigation audit . They are important because they help you to schedule irrigation runtimes and ensure adequate water coverage of the area . If you want to conduct you own audits , there are several extension publications available online to lead you through the process . An audit is a great place to start in your quest to refine your irrigation scheduling , because it can reveal needed component repairs and adjustments while providing data to refine zone runtimes and compensate for poor coverage .

Along with the technologies mentioned , there are several best irrigation strategies that you should review . These are listed in BMP documents available from the STMA . By introducing new technology and initiating a few new strategies , you can have quality turfgrass with minimum water use . And since most of the new technology is automated , it may give you more time to concentrate on other things .

SFM

Grady Miller , Ph . D . Professor and Extension Turf Specialist North Carolina State University

Questions ? Send them to Grady Miller at North Carolina State University , Box 7620 , Raleigh , NC 27695- 7620 , or e-mail grady _ miller @ ncsu . edu Or , send your question to Pamela Sherratt at 202 Kottman Hall , 2001 Coffey Road , Columbus , OH 43210 or sherratt . 1 @ osu . edu

50 SportsField Management | September 2021 sportsfieldmanagementonline . com