The past several weeks of cool temperatures have given us some frost and slow growing weather for courses with warm-season grasses. These lower-than-average temperatures have been coupled with limited rain, high skies, wind and low humidity, which means evapotranspiration has been high in spite of the cool weather. The rain outlook has changed little, but the temperatures are forecast to rise. At least we can transition from knit hats and dragging hoses to ball caps and dragging hoses.
While it’s frustrating to deal with dry weather this early in the season, it does present an opportunity to train staff on properly using portable moisture meters. The temperatures are cool, which allows a little room for error when watering and it gives an opportunity for staff to reacquaint themselves with the hand watering process from last season – or for new staff to practice for when the heat is on. Portable moisture meters are manually probed into the turf to measure the ratio of water volume to soil volume, which is typically expressed in a percentage known as volumetric water content (VWC). This is the number turf managers use to gauge how much water to add, if any, for the turf to survive through the day.
There are factors that influence what the right number is for a given area and explain why certain areas tend to be wetter or drier. Low-lying or shaded areas will generally have higher VWC numbers with the same amount of rain or irrigation whereas mounds, south-facing slopes and areas with poor irrigation coverage can give lower VWC numbers. Determining your threshold VWC for a particular area and knowing when to add water will become clear based on how the turf performs. Hand watering is usually the best option to even out site-specific deficits, but it is labor intensive which may restrict how much area can be managed with precision hose work.
Using portable moisture meters to improve the uniformity of water content in the soil will benefit turf health and playability. Here are a few water management tips to keep in mind as you get ready for the summer ahead:
- Too much water is just as bad as not enough and can “cook” the turf, so it’s important to find the right moisture balance.
- Increasing the duration of leaf wetness increases disease potential. Avoid unnecessarily applying water when the risk of disease is high.
- Hand watering helps conserve water since it’s applied with greater precision than overhead irrigation.
- Drier turf tends to be firmer turf that will be more resistant to ball marks and damage from traffic.
During dry weather, a good practice is to apply water deeply with the overhead irrigation and then allow the turf to dry down, carefully monitoring VWC with portable moisture meters and evening moisture out through hand watering. This practice of deep and infrequent watering will produce a greater number of roots, deeper roots and a larger root surface area that helps the turf during the stresses of summer. It is also helpful to collect this VWC data throughout your course, essentially mapping wetter and drier areas to dial-in watering practices. Finding your “number” for the different areas of the course will help keep the turf in healthy condition and improve playability.
Northeast Region Agronomists
Darin Bevard, senior director, Championship Agronomy – dbevard@usga.org
Elliott L. Dowling, regional director, East Region – edowling@usga.org
Brian Gietka, agronomist – bgietka@usga.org