BMP CASE STUDIES
Recycled Water And Seashore Paspalum—A Perfect Match May 11, 2017 | Turtle Bay Resort, Kahuku, Hawaii By USGA Green Section

Seashore paspalum’s aggressive, spreading nature helped it overrun many areas at Turtle Bay and allowed it to outcompete goosegrass weeds.

 

Issue

The two courses at Turtle Bay Resort on the island of Oahu were planted initially with various hybrid bermudagrasses. However, an unwanted invader came along with the sprigs used for the fairways and roughs, seashore paspalum. This salt-tolerant grass was generally considered to be a weed, yet every effort to remove it from the golf courses failed because there is not a herbicide that can selectively remove paspalum without damaging the surrounding bermudagrass.

Another reason seashore paspalum continued to thrive at Turtle Bay was the introduction of reclaimed water for irrigation. This new water source was high in salts and contained a small amount of nitrogen. Seashore paspalum thrives under elevated salt levels and minimal nitrogen, so irrigating with reclaimed water proved to be a turning point that caused paspalum to overrun the bermudagrass at Turtle Bay.

 

Action

Rather than fight a losing battle against seashore paspalum, Superintendent Mike Honma decided to take advantage of paspalum’s suitability for the site and allow it to expand into more areas of the golf course. Eventually the resort became the first in Hawaii to convert their greens to SeaIsle 2000 seashore paspalum, a dwarf version of the grass suitable for putting greens. The remainder of both courses was allowed to convert naturally to seashore paspalum over time.

 

Results

Converting the courses to seashore paspalum has brought Turtle Bay positive results. Paspalum’s overall water requirements are not much different than bermudagrass, but Turtle Bay’s reclaimed irrigation water and cloudy winter conditions have made seashore paspalum a perfect choice for the site. The nitrogen content of the reclaimed water alone has proven sufficient for seashore paspalum, allowing Mr. Honma to discontinue nitrogen fertilizer applications on some fairways for as long as 10 years. The once massive goosegrass population has disappeared without extensive herbicide use because seashore paspalum outcompetes this weed.

Seashore paspalum has had some issues with disease over the years, but it has proven vastly superior to bermudagrass on this site. While seashore paspalum is not bulletproof, it has proven to be the optimum grass for Turtle Bay. As Mr. Honma says, “I sleep much better at night knowing what the course will be like in the morning.”

 

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