WE KNOW TURF: Lawn Watering
A practical watering program embodies three basic concepts. Each concept may be set forth as a question?
- How should water be applied?
- How much water should be applied?
- How often?
While basic concepts of a good irrigation program may appear simple, in actual practice such a program is complex.
The amount of water to apply at any one time will depend upon the water-holding capacity of the soil, the infiltration rate, the amount of soil moisture present when irrigation is started, and the drainage from the area watered.
Sandy soils must be watered more frequently than loam or clay soils. A sufficient amount of moisture should be applied to wet the entire root zone. Once the soil is wet throughout the root zone, any additional water applied will merely fill the large soil pores and be "excess".
The soil organic matter is a major factor in turf grass growth and development because it contributes to improved soil structure, aeration, water retention, water movement, and nutrient availability. The addition of organic matter may substantially improve the water-holding capacity of the soil.
Frequency of irrigation depends on type of grass, the soil's physical properties, and climatic conditions - especially rainfall, humidity, temperature and wind movement.
Many turf grass problems are the result of improper watering. Adequate water is essential for maintaining optimum growth, density and color. Natural rainfall is generally adequate during the cool Spring and Fall periods; however, extended drought periods during Summer may cause the grass to wilt and turn brown. Although it may look unattractive, a lawn that is brown and dormant in Summer will usually recover with the return of cool weather.
If a high quality appearance is desired throughout the season, the lawn should be irrigated as soon as the grass shows signs of wilting. Apply enough water to moisten the soil to a depth of at least six inches. This will develop a deep root system which can better survive drought. In regions of high Summer temperatures it may be necessary to irrigate the lawn several times a week. It is important that sprinklers deliver a uniform amount of water over the area covered by the sprinkler throw. You can check your sprinkler output by placing a row of one pound coffee cans (or any cans of equal size) in a line at one to two foot intervals from the sprinkler to the point of furthest throw. By allowing the sprinkler to run for a given time (1 /2 to 1 hour), the amount of water in each container can be measured and these results plotted to show the distribution pattern and application rate of that particular sprinkler. This procedure should be used at a time other than during periods of peak community water use when water pressure may be lower than normal.
Poor water distribution also can be caused by leaving a stationary sprinkler in one area too long. This can be overcome by using a traveling sprinkler that moves over the area at a uniform pace.
Sound water practice should provide for proper distribution of water, permit good water infiltration, encourage sufficient water retention in the soil to support plant growth without irrigation for a reasonable time, and provide for the removal or drainage of excess water. Finally, an effective watering program should provide only as much water as is needed by the turf grass plants to produce healthy, vigorous, wear-resistant turf.
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