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Grass selection is a fundamental part of successful golf course management. Different grass species – and even different cultivars of the same species – can have a significant impact on the maintenance requirements, aesthetics and playability of a golf course. The availability of improved turfgrass cultivars, changing weather patterns, and shifting priorities in playing conditions have led many courses to make grassing changes in recent years. Increased use of warm-season grasses in dry and transitional climates is a great example. Water conservation is a driver of this trend, but the desire for better playing conditions for more of the year is also a key factor.

When it comes to saving water through grassing changes, rough and fairway areas offer the greatest opportunity simply because of how large they are. Renovation costs can be high and there will be downtime when play is not possible, but water and cost savings can be significant in the right situation, and increased golfer satisfaction with better playing conditions is also extremely valuable. This article provides an overview of the different ways that grassing strategies can be used to help golf courses save water. The grassing strategies for water conservation chapter of the USGA Water Conservation Playbook covers this topic more broadly and in greater detail.

Benefits

Expected Water and Cost Savings

Cool-season to warm-season conversions will deliver the largest water savings – often 25% or more (Whitlark, 2022; Whitlark et al., 2023). Replacing a cool-season grass with a more drought-resistant cool-season option or a warm-season grass with a more drought-resistant warm-season option can decrease water use in those areas by 10% to 20% (Amgain et al., 2018; Ketchum et al., 2023; Minor et al., 2020; Serena et al., 2023). Actual savings will depend on differential water use between existing and new cultivars and various site conditions.

For courses with high water costs, such as in the southwestern U.S., the savings associated with using a cultivar that requires less irrigation can help a conversion project pay for itself in a relatively short period of time. Many conversions can pay for themselves in just a few years (Minor et al., 2020), and even multimillion-dollar projects can break even in less than eight years, especially when considering other cost savings from improved cultivars such as reduced fertilizer and pesticide use (Whitlark, 2022). Turfgrass conversion projects have a range of costs, and the ultimate payback period will mostly vary depending on grassing method, management costs of the old and newly established grass, and lost revenue during the project.

Improved Playing Conditions

One of the biggest motivations for converting to grasses that use less water is the prospect of better playing conditions. Using cool-season grasses in areas with hot summers often means there will be higher water use and softer conditions through some of the primary playing season. Converting to grasses that use less water and are more drought-resistant means playing surfaces can be kept firmer and healthier during these times. Courses that have an evolved mix of various grasses on a particular playing surface will also realize improved conditions with a uniform stand in converted areas.

Addressing Salinity Issues

Many golf courses deal with water quality issues – including high amounts of salt. Warm-season grasses can generally make better use of lower-quality water, which improves water-use efficiency when compared to cool-season grasses in these scenarios. Warm-season grasses also make it easier to use recycled irrigation water and need less leaching to reduce salt accumulation. Within warm-season grasses, there are species such as seashore paspalum that better tolerate higher salt content in irrigation water.

Considerations

Selecting the Right Turfgrass

Many factors go into selecting the best possible turfgrasses for a particular course and there are plenty of resources available to help decision-makers choose which route to go. The USGA Green Section, university extension programs, the National Turfgrass Evaluation Program, the Turfgrass Water Conservation Alliance, and the Alliance for Low Input Sustainable Turf provide science-backed information about all major turfgrass species that can aid in decision-making. We also recommend doing in-house trials with possible turf options to allow golfers, decision-makers and others to view the characteristics of each grass and understand how they perform given the unique site and management conditions at a particular course.

Climate Zones and Turf Adaptation

Climate – including light, temperature, precipitation and wind – is a key factor in grass selection. Converting from cool-season to warm-season grasses might save water during the summer at a particular course, but if that course is also prone to extremely cold winter weather the risk of turf injury may be too high for warm-season grasses to be a viable option. While the ranges of turfgrass adaptation are continually shifting and stretching with the development of new varieties and changing weather patterns, there are limits and trade-offs that must be acknowledged.

Managing Adjacent Surfaces

A challenging aspect of converting some playing areas to drought-resistant grasses is how to manage adjacent areas with different grasses that have different water requirements. This is a common issue when converting cool-season fairways to warm-season turf, but not the adjacent rough. Unless the irrigation system already can (or is redesigned to) irrigate fairways and rough separately, the rough will likely experience drought stress and other issues under an irrigation regime designed for the warm-season fairways. If this is not acceptable, the rough may also have to be converted to fully realize potential water savings and optimize conditions in both areas.

Another issue with having different turfgrasses adjacent to one another is the potential for encroachment and contamination. There are various ways to create buffers and manage encroachment, but there will likely be a constant struggle any time different grasses are located next to each other.

Implementation

Converting to Warm-Season Grasses

Transitioning from established cool-season or warm-season grasses to a new warm-season grass that uses less water involves completely renovating the turf area. Eliminating the existing grass takes time and patience. The process begins with multiple applications of glyphosate and allowing regrowth in between applications. Carefully manage the timing between the final glyphosate application and planting or seeding the new turf. To prepare the soil after herbicide applications, vertical mowing, aeration and scalping will help remove as much of the surface material as possible. Depending on the planting method, till or no-till options are available. When planting the new grass, sprigging is less expensive than sodding but will take longer to establish, so the total cost difference may not be significant when factoring in lost revenue from additional closure time. Both sprigging and sodding have pros and cons that should be considered depending on your location’s needs.

What if Warm-Season Grasses Aren’t Possible?

If warm-season grasses are not an option due to the climate, there are some cool-season species and cultivars that exhibit better drought tolerance than others. It is recommended to select several possible cultivars with promising research and field results and test them at your course under your unique site conditions and maintenance program before making a final decision. The water savings in these scenarios may not be large, but there can be significant improvements in turf health, playing conditions and overall maintenance efficiency that can generate other cost savings.

Eliminate Winter Overseeding

Eliminating overseeding of warm-season grasses can significantly reduce water use. Well-maintained bermudagrass, when dormant, can provide an excellent playing surface. Additionally, zoysiagrass may be a good option for non-overseeded playing surfaces as it offers a firmer and denser surface that is more resistant to divot and traffic injury. Using pigments or colorants to maintain a green appearance can help enhance aesthetics during dormancy if that is a consideration.

Tips for Success

Measure current water use and establish a target.

The first step in successful water conservation is to accurately measure current water use to establish a baseline. Once this is done, set a target for water reduction. If turf conversion is part of your water conservation plan, this baseline information will help you choose a species or cultivar that helps meet your goals. It is important to have realistic expectations and to recognize that water savings will not be at their full potential in the early years of establishing new grasses.

Establish test areas at your course.

Establishing small-scale test areas in challenging parts of the course, such as high-traffic zones or areas prone to drought stress, allows you to test the performance of different turfgrass species. Manage these plots according to best practices and observe their performance over two to three years. During this period, gather feedback from stakeholders, including course staff and golfers, to assess playability and overall satisfaction with the grassing options.

There are pros and cons to every regrassing method.

It can be difficult to decide between sodding for immediate cover or seeding/sprigging, which both require longer times for establishment but cost less in materials and installation. There are agronomic benefits to seeding or sprigging, but those can be outweighed by timing considerations. Whatever grassing method you choose, try to allow more than enough time to eliminate the existing grasses, prepare the soil and establish the new turf. Too many courses struggle with turf conversions simply because they did not allow enough time to do the job properly with the many unpredictable variables involved.

Be patient and adjust management practices to realize benefits.

After planting, allow sufficient time for the turf to become fully established before subjecting it to regular play. Once the grass is established, management practices – particularly irrigation – must be reviewed and adjusted to reflect the needs of the new turf. Patience during this period is critical for long-term success. The peak playing conditions and full water conservation potential of a new grass will not be realized likely for several years after planting. While this may not be what golfers and decision-makers want to hear, it is the reality of a long-term investment in better and more-sustainable turfgrass.

References

Amgain, N.R., Harris, D.K., Thapa, S.B., Martin, D.L., Wu, Y., & Moss, J.Q. (2018). Evapotranspiration rates of turf bermudagrasses under nonlimiting soil moisture conditions in Oklahoma. Crop Science, 58(3), 1409-1415. https://doi.org/10.2135/cropsci2017.08.0493

Ketchum, C., Miller, G., & Pinnix, G. (2023). Stress coefficients for hybrid bermudagrass in the transition zone. Crop, Forage & Turfgrass Management, 9, e20212. https://doi.org/10.1002/cft2.20212

Minor, J., Campbell, B., Waltz, C., & Berning, J. (2020). Water savings and return on investment of a new drought resistant turfgrass. Journal of Environmental Horticulture, 38(2), 56-62. https://doi.org/10.24266/0738-2898-38.2.56

Serena, M., Morris, K., & Petrovsky, J. (2023). Measuring and comparing the water requirements of warm-season grasses. USGA Green Section Record, 61(15).

Whitlark, B. (2022). Converting to bermudagrass fairways. USGA Green Section Record, 60(14).

Whitlark, B., Umeda, K., Leinauer, B.R., & Serena, M. (2023). Considerations with water for turfgrass in arid environments. In M. Fidanza (Ed.), Achieving Sustainable Turfgrass Management. Burleigh Dodds Science Publishing. http://dx.doi.org/10.19103/AS.2022.0110.21