Water Tap

Effective water resource management is quickly becoming the most important environmental issue of many municipalities throughout the country.

It is no secret that turf grass, a living organism, needs water to survive, but are we managing our turf areas wisely to ensure we are providing enough water without wasting this precious resource?

There is no set answer to the question: “How much water does turf grass need?” Due to many variables — like turfgrass species or cultivar, soil texture, soil structure and environmental conditions — it is extremely difficult to accurately determine. However, there are things you can do to mitigate water usage and still maintain quality turfgrass.

Quantity & Quality

Water resource management takes two forms — water quantity and water quality. Here, we’ll focus primarily on water quantity. In other words, how can we maintain our sports turf and other turf grass areas to high standards and still reduce the amount of water we currently use?

First, we’ll look at the turf grass plant and its need for water, then we’ll look at managing that need most effectively and efficiently.

The living portions of a turf grass plant can be up to 80 percent water. Water is used by the plant to transport nutrients and organic compounds, to maintain turgidity (stiffness), is a requirement in and is a part of many metabolic processes within the plant, and — through the process of transpiration — helps the turf grass plant control temperature. In fact, turf grass uses more water to control temperature than any other function.

Transpiration is the process by which turf grass roots take up water from the soil, then deposit it into the atmosphere through stomata (tiny openings in the leaf tissue that open and close) as a vapor.

It is this process of changing water from a liquid to a gas, that energy is used with the result being cooler temperatures, i.e. evaporative cooling. Together, evaporation and transpiration provide us with a measurement called evapotranspiration (ET).

Some of the factors that increase ET are temperature, humidity, wind and turf grass vigor. To answer the question posed earlier, turf grass ideally needs the amount of water that is lost through ET. The difficulty is that ET can be drastically different from one point to another, even just a few feet away.

On the good side, turf grass has adapted to deal with fluctuations in water amounts. Stomata will close to slow the release of water into the atmosphere, wilting will begin to change the orientation of the leaf blades to the sun, and as the water supply lessens the plant will go into dormancy, conserving water for the crown of the plant which must be kept alive for re-growth.

There is also strong evidence that stressing a plant through a lack of water will aid in deeper roots as they grow to seek a water source.

A moderate amount of stress from a lack of water is good for the grass. Deep and infrequent watering will produce deeper roots and use less water. The whole idea is that grass with a deep root system will be healthier and require less water than one with a shallow root system.

Soils also play an important part in water use and conservation. Most new golf course tees and greens as well as many sports fields are being constructed with a sand-based root zone that has large pore spaces to increase drainage, minimize compaction and promote deep rooting.

When constructed properly, water will quickly drain through the upper surface, then form what is called a perched water table deeper in the soil profile. This water table then provides a water reservoir deep in the root zone to encourage deep rooting.

Conversely, soils with high percentages of silt and clay have smaller pore spaces, making it more difficult for roots to penetrate. They also have a tendency to puddle water at or near the surface, which leads to shallow rooting. The small pore spaces also limit water infiltration into the soil.

A sustained program of core aerification and top dressing with sand can increase rooting depth, water percolation and a medium for gas exchange, all of which produce a stronger plant.

I highly recommend having both your existing soil and your proposed topdressing sand analyzed for compatibility prior to starting a program.

I highly recommend having both your existing soil and your proposed topdressing sand analyzed for compatibility prior to starting a program. There are many quality soil testing labs in the country. Contact your extension representative or land grant university for a lab in your area.

Conservation

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