Writer: D'Lyn Ford
FARMINGTON - Homeowners and turfgrass managers in northwestern New Mexico can conserve water and still grow lush green lawns if they follow recommendations from New Mexico State University's Agricultural Science Center at Farmington.
NMSU researchers studied turfgrass varieties for the Four Corners area to find out which ones make the best use of water while still providing acceptable coverage and quality green color. The study also provided data for precise lawn watering recommendations for each species, something previously lacking for northwestern New Mexico.
"We can now recommend alternative grass species with acceptable quality that use less water and are generally more drought tolerant than the Kentucky bluegrass that is so commonly grown up here," said Dan Smeal, agriculture specialist who headed the study.
"For those folks who don't want to move to more water-efficient varieties, we can offer precise calculations on the minimum amount of water needed to maintain quality with the grass they are already growing. That's something that benefits everybody, from park and golf course managers to homeowners."
The project compared water use rates for several varieties of warm- and cool-season turfgrasses. Cool-season varieties such as blue grasses, rye grasses and fescues generally grow best during cooler months, allowing them to green up in early spring and retain their color until late fall. Warm-season varieties such as buffalo and Bermuda grasses grow best in the hot summer months, giving them a shorter growing season.
Researchers planted 14 grass varieties–seven cool- and seven warm-season–and tested gradient-staggered watering levels. Growth rates for each species were recorded during 1998, 1999 and 2000. The center also invited 10 master gardeners from San Juan County to judge grass quality during each season, rating greenness, density, uniformity, disease problems and blade texture.
Overall, the study showed the nonnative, cool-season varieties tested needed about 40 percent more water to stay lush than the native, warm-season varieties.
"The shorter growing season for warm-season grasses cuts down on water use, but we also found they need less water on a daily basis to maintain acceptable quality than cool-season varieties," Smeal said. "They're just more drought tolerant, which is logical for varieties such as buffalo grasses that are native to the semiarid conditions here."
During droughts, warm-season grasses turn brown but green up again when the drought ends, Smeal said. In contrast, stands of cool-season grasses don't survive.
"They thin out and get clumpy, making recovery much more difficult," he said.
Although master gardeners gave most of the warm-season varieties acceptable quality ratings, the cool-season grasses were much greener and fuller, giving them greater appeal.
"Although the warm-season grasses use significantly less water, it will be hard to convince people not to use the greener cool-season grasses," Smeal said. "But at least now, with the data we've compiled, we can make concrete recommendations on minimum daily water use for cool-season varieties, something we couldn't do before."
A flowchart that shows water-efficient irrigation schedules for optimum greening of each of the 14 varieties studied will soon be made available online and in print through NMSU's Cooperative Extension Service, Smeal said.
Meanwhile, research will continue at the center on additional buffalo grass varieties, and on more drought-tolerant cool-season grasses.
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