Perfecting Turfgrass
A delicate balance
Many athletes don’t like artificial turf. They say it’s hot, uncomfortable to run on, changes the way a ball moves, and studies show it causes more non-contact injuries than a natural playing surface. Professional women’s soccer players even started a lawsuit over FIFA’s decision to use artificial turf in the 2015 Women’s World Cup.
A PERFECT RESEARCH OPPORTUNITY
Some universities—including Brigham Young University—have responded by using natural turf fields in the majority of their playing surfaces. The challenge for these natural surfaces is to develop management practices that help the turf stand up to frequent use and allow it to perform well even during those periods of high traffic and suboptimal weather conditions. It’s a perfect research opportunity.
PERFECTING WATER AND NUTRIENTS FOR OPTIMAL PERFORMANCE
BYU turf professor, Dr. Bryan Hopkins, and his colleagues in the Plant and Wildlife Department, have set up a new state-of-the-art facility to study a variety of soil and plant health indicators in both a greenhouse and natural setting. The facility includes a large selection of turfgrass species and cultivars used in residential landscapes and sport fields.
BEFORE SOIL SENSORS
Initially, BYU maintained the turf facility with a standard, timer-based irrigation controller, but over time they realized that understanding the performance of their turf relative to moisture content and nutrient load is crucial. One year during Memorial Day weekend the irrigation system stopped working and no one was around to notice. During those four days, temperatures rose to 40 °C (100 °F), and a large section of turf, meant to replicate the football stadium, slipped into dormancy due to heat stress.
ENVISIONING A FAILPROOF SYSTEM
In response, Dr. Hopkins began imagining a system of soil moisture sensors to constantly monitor the performance of the plants. He wanted not only to make sure the turf never died but also to really understand the elements of stress so they could do a better job maintaining a healthy stand of turf while also reducing inputs.
WATER CONTENT + WATER POTENTIAL—BETTER TOGETHER
Soon after, fellow scientists, including Dr. Neil Hansen, installed METER water content and water potential sensors to measure water moving beyond the root zone. Combining these measurements, they could clearly see when the plant reached stress conditions and how quickly the turf went from showing signs of stress to entering dormancy. Ancillary measurements of temperature and electrical conductivity provide an opportunity for modeling surface and root zone temperature as well as fertilizer concentration dynamics.
ERRORS REVEALED
What the researchers learned was that they were using too much water. Dr. Colin Campbell, a METER scientist who worked with BYU on sensor installation, says, “We found in the first year that the plants never got stressed at all. So we allowed the water potential at 6 cm (~2.5 in) to drop into the stress range while observing WP at 15 cm (~6 in), reducing irrigation inputs in order to push the roots deeper.”
In turfgrass, drought stress is not the only problem. Overwatering leads to fungus and removal/flushing of nutrients, which costs money and time to correct. In the video below, Dr. Campbell explains why there is often a fine line between too wet and too dry. Monitoring both water content and water potential keeps turfgrass at optimal moisture levels.
WHAT THE FUTURE HOLDS
In addition to monitoring what was happening in the soil, the researchers wanted to monitor what was happening above ground. So, they installed an ATMOS 41 weather station and NDVI sensors. The weather station provides several data points, including values of evapotranspiration, which helps with irrigation scheduling. The NDVI sensors provide information on canopy health/stress. Seeing all this data in ZENTRA Cloud (METER’s data software) will enable them to see the impact on the plants as the turf is drying down.
Click the link below to read the full version of the BYU story with detailed graphs.
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