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Gazing in the Grass... Clearly, water must be cleanFew environmental issues raise as much rancor as the perceived effect golf courses have on water quality. Studies show that there is a sense of unknown and loss of control by those who see a nonessential activity such as golf as a potential cause for contamination of drinking water supplies. From a health perspective, there is great concern that contaminated water can be the cause of long-term health issues. Effects of reduced water quality can be acute, but often the chronic effects from continuous exposure are what we must guard against. Millions of dollars have been spent trying to determine the effects of golf turf management on water quality. How many maintenance practices that could adversely affect water quality are conducted purely for cosmetic effect? Does the golf industry have at its disposal any research that dispels this belief and shows that there are reasons why we must apply chemicals to the turf? The Northeast is experiencing an unusually dry fall on the heels of an exceptionally arid summer. Beyond the obvious water needs of the plant to sustain turf quality, we often fail to consider the influence that irrigation might have on fertility needs and on increasing leaching nitrogen through the system. Possible nitrogen leaks Studies have shown there are significant pools of nitrogen stored in soil organic matter. As turf ages, it contributes regularly to these levels. Researchers at Michigan State University who are investigating long term nitrogen leaching demonstrated that as the turf ages and fertility programs are not adjusted, concentrations with the potential to enter ground water can exceed the U.S. Environmental Protection Agency’s health advisory limit. Clearly, there are many factors involved, but it could be that turf systems leak some nutrients. Stored nitrogen can be released when soils warm, however, soil warming typically coincides with dry weather conditions that reduce microbial activity when soils dry. They also can fluctuate from very dry to saturated. Maintaining adequately watered soil during warm conditions probably will act as a slow-release fertilization program and reduce overall nitrogen fertilization needs, however there is little research in this area. When we look at the combined potential for our system to leak when we are not precise, allow things to runoff when we do not apply properly and focus on visual quality instead of the functional aspects of turf, then we had better be prepared to be regulated.Many fertilizer studies do not have an unfertilized control. Often this is a mistake, as it could reveal a lack of influence of applied fertilizer over the unfertilized plots, likely as a result of a significant nitrogen contribution from the soil under well-watered turf. This said, while irrigation could reduce overall nitrogen needs of turf, there are other aspects such as soil type, clippings returned, traffic needs, etc., that influence nitrogen needs. Furthermore, considerable evidence suggests over- irrigation can increase leaching of nitrogen below the turf and must be considered when trying to develop environmentally sensitive fertility programs. Runoff concerns The high percentage of our population dependent on groundwater as a drinking source explains the high concern for leaching. However, a good part of the country is equally dependent on surface waters not simply for drinking but recreation and for wildlife habitat. If the concern for groundwater is nitrogen entering the water table, then there is equal concern for phosphorus entering surface water. Many recent studies show growing evidence that fertilized turf is not a primary source of phosphorous runoff into surface water. Despite evidence that turf is not a source for significant phosphorous runoff, use of phosphorous fertilizers has been banned in many areas. In general, the concern appears to stem from the potential for misapplication on paved surfaces, not golf courses. Nevertheless, golf courses do have significant surface water that can be directly impacted by misapplication. Cosmetic perception The concern many legislators and voters have regarding use of pesticides and fertilizers that could contaminate water supplies is that they are used primarily for cosmetic purposes. Laws are on the books in Canada that ban the use of pesticides and fertilizers for cosmetic purposes. Although such laws are directed mostly at residential users, they affect golf courses as well. Similar laws have been under consideration in parts of the United States for years. Canada has been successful in promulgating this legislation for private property, so far something considered taboo by U.S. lawmakers. I do not expect private-property laws to be overturned for this issue, but there are broader environmental concerns to this debate. Do the public and legislators see the use of fertilizers and pesticides in turf simply for looks? Do we have research that demonstrates the functional need for product application? When we look at the combined potential for our system to leak when we are not precise, allow things to runoff when we do not apply properly and focus on visual quality instead of the functional aspects of turf, then we had better be prepared to be regulated. Uninformed regulation could have widespread negative effects on environmental quality. Dense vegetation does reduce runoff and leaching, but must it be emerald green all season? Must turf be completely weed-free to benefit the environment, or is this simply a visual perspective? We need answers to questions of cosmetic applications soon, as the environmental debate will continue to mature and the stakes will be higher. Frank S. Rossi, Ph.D., is associate professor of turfgrass science at Cornell University in Ithaca, N.Y. He can be reached at fsr3@cornell.edu. |
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