Irrigation and Syringing

Published March 4, 2004

As one of the basic plant needs, water is one of the most critical when it comes to the plant's ultimate survival. As with many things in life more is not always better and not enough can cause problems. This is especially important as the majority of our turf is composed of annual bluegrass (Poa Annua). "Poa" is a very shallow rooted winter annual and when it dies of moisture stress it will not recover until new plants germinate in the fall. Monitoring water needs and balancing the plants health with the playability of the golf course is challenging to say the least.

Of greatest importance is the need to apply water uniformly across the playing surfaces. Like many golf courses this is difficult because of varying topography and differences in soil structures throughout an individual golf course. The high areas tend to remain drier as opposed to the lower areas and the heavier soils are more apt to retain moisture longer than a more porous soil only a few yards away. Microorganisms often distribute secretions that make soil particles hydrophobic, making it difficult to move water into these areas. It is not uncommon, at any given time, to have different areas on an individual green or fairway that have moisture levels at opposite ends of the spectrum.

Another limiting factor is the efficiency of the irrigation system. Even the best irrigation systems have limits as to their ability to provide water uniformly, not taking into account the affect that wind can significantly alter the distribution of water applied to the turf. The efficiency of the irrigation system is most relevant to us as our system is far from providing us with the efficiency and flexibility needed to meet the demands of today's golfing community. With all of this in mind it is safe to conclude that irrigating the golf course is not as easy as just turning on the water and letting it go at that.

In determining the watering cycles on our golf course we take into account many factors. Included among those factors are: evapotranspiration, soil moisture monitoring and visual plant stress as well as the weather forecast. Evapotransporation (ET) is the sum total of plant water loss derived from transpiration and evaporation. As part of determining our water needs we use regional ET loss estimates as a guide to determine how much water needs to be replaced. In general, in our area this fluctuates between .1 and .25 inches of water lost to the atmosphere on a typical summer day.

During the summer months those of you playing in the evening will frequently see me out on the golf course with a soil probe. By visually inspecting the soil moisture I can determine the average moisture content and use this information as part of my decision making process. Another indicator of water requirements is visual plant stress. We've all seen what happens when a plant is lacking water. The leaves droop and start to curl and often change colors. During the evening you can easily see the areas that are suffering from moisture stress.

By taking all of the above into account and gambling on the weather forecast, a decision will be made on when, where, and how to water the golf course. This may include a hand watering only, a complete irrigation cycle or a partial cycle or a combination based on the golf schedule and the work load. I may determine that hand watering is needed but cannot be implemented because of labor considerations or a full golfing schedule that prevents us from being active on the golf course. Since it is almost impossible to evenly water the golf course with our current irrigation system and the scenario I described above, the act of syringing plays an important part in our watering regime.

Another consideration to watering the golf course is plant disease. It's been said that "mold doesn't grow on toast." Similarly, mold and turf diseases are less apt to establish under turf conditions favoring the dry side. By taking this approach we have been able to reduce our applications for disease control as well as reduce the amount of water used on an annual basis.

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