Irrigation

      Gardening with the Masters

Water conservation can be more completely achieved by looking at the various ways water is used and/or wasted. Last week’s article focused on mulching as a means of reducing evaporation and run-off. Today's article (courtesy of Clay Robinson, Ph.D., Assistant Professor of Plant, Soil and Environmental Science at WTAMU) deals with irrigation methods and water usage. Next week we will tie good mulching practices, efficient irrigation, plant selection and limiting of turf grass together for a well-rounded approach to water conservation.

When was the last time you saw water running down the gutter from a neighbor's (or your own) lawn or from a local business as they watered?  Students on WTAMU campus regularly comment they do not believe the sidewalks will grow, though sometimes they are covered with water while the sprinklers are running.

These are common sights in the Texas Panhandle, though they are wasteful and unnecessary.  There are a few principles to have an efficient system for lawn/turf/garden irrigation.

Maintenance.  If you have an installed irrigation system, regularly check the sprinkler heads for damage and orientation.  Other yard work sometimes damages the heads, or redirects them so they no longer hit the desired target.  Most ½ or ¼ pattern sprinkler heads can be adjusted by hand so they do not spray on the sidewalk or street.  A damaged head can alter the distribution pattern for a complete station (group of heads that operate at the same time).  Keep a few extra sprayer parts
available to do repairs: pop-ups and spray heads.  The sprayers have a variety of configurations or patterns: full, 3/4, ½, and 1/4 circle; flat or low angle spray; mist or impact heads; 6, 8, 10, ... feet diameter; etc.  Check your current configuration and brands and get some spare parts.  Check to see the spray pattern falls on the lawn, not the sidewalk, driveway, house, etc.

If you do not have a sprinkler system installed, what is the best way to water your lawn?  Several sprinklers that attach to garden hoses are available.  Of these, avoid any sprinkler that produces a fine mist or launches water skyward (blows in the wind and evaporates too easily).  The best sprinklers to purchase are the lawn tractor and impact sprinklers.  These are the most efficient garden hose sprinklers for our region.  You can set them to avoid sidewalks, driveways, etc.  Water early in the morning, and avoid watering on days with high winds.  If water begins to run off your lawn, you are applying water faster than the soil can accept it.  Turn off the water and try again later.  For more information, visit the Texas Water Development Board homepage:
http://www.twdb.state.tx.us/conservation/pubs.htm

If you have a row of trees or shrubs, or a bed of ornamentals, drip systems or soaker hoses are the best way to go.  Some ornamentals and shrubs are sensitive to the salt content of the water and die when the salts accumulate on their leaves.  Drip systems and soaker hoses apply the water directly to the soil, not to the vegetation.

Another common question is how long and how often should you water your lawn?  To determine your application rate, place 5 empty cans (tuna fish cans work well) or cake pans randomly in your yard.  Turn the sprinkler system on for 30 minutes.  Turn it off and measure how much water accumulated in the pans.  If the pans have ½ inch of water, in them, your system applies 1 inch of water per hour.  Next you need to watch the local weather.  At least two of the local stations include the daily ET (evapotranspiration, estimated water lost from the lawn) in their weather coverage.

In a hot week, a lawn can use 1.5 inches of water or more.  If your system applies 1 inch per hour, you would need to run the system for 1.5 hours to provide 1.5 inches. If you get runoff when after one hour, stop and apply the rest of the water on another day.  So if you know the application rate, and you know how much water your lawn has used, you can determine how much you should apply.

There is another simple tool that is good for the homeowner to have, a soil moisture probe.  These are available from the local Master Gardeners for $12.00.  If you can push the probe 3 feet into the ground, your irrigation system is doing what it should.  If it goes deeper into the ground, you can decrease your water application. If it only goes into the ground one foot, you need to apply more water than is required by the ET estimate alone to recharge the soil.

With these simple procedures, you can use water more efficiently and see less runoff on sidewalks, driveways, and gutters.

Next week…
Water conservation doesn’t have to be a dry subject.

Mail your questions or requests, along with a
self-addressed, stamped envelope to:
“Gardening with the Masters” c/o Samantha Scott
Amarillo Globe News, P O Box 2091, Amarillo, TX  79166
or e-mail sscott@amarillonet.com

Go to Clay Robinson, Ph.D., CPSSc	Plant, Soil and Environmental Science Faculty
WTAMU Homepage	Division of Agriculture