| Abstract/Contents: | Several plant characteristics aid wear tolerance: the more the total biomass above ground the better, high lignin and cellulose content in the shoot, and a high proportion of sclerified tissues, which are specialized tissues that give strength and rigidity to the tissue. More lateral shoots (rhizomes and stolons) relative to the leaves will aid wear resistance, and aid recovery from traffic stress. Factors contributing to traffic recovery are, growth rate, whether rhizomes remain from which new turf can grow, the number of meristematic growing points from which new shoots can arise, and carbohydrate reserves. For instance bermudagrass has a more rapid recuperative rate than does zoysiagrass. As a rule, species that spread only by tiller have lower recuperative rates and potentials than those which develop both rhizomes and stolons. The author used a wear simulation device to test various species' wear rates. The device rotated about a post dragging a heavy weight, and counted the number of turns needed to wear away all turfgrass tissue. Zoysiagrass tolerated the most turns- more than 15,000 turns. It is a wear resistant grass that, once injured, is slow to recover. Mature bermudagrasses tolerated 2000 to 5000 turns. Perennial ryegrass, Kentucky bluegrass and tall fescues were in the 500 to 800 turn range. Rough bluegrasses and bentgrasses tolerated only 100 to 300 turns. The author also tested 16 bermudagrass cultivars, in August, the peak summer heat and drought-stress period in College Station, Texas. He established three plots of each cultivar, located randomly throughout the test area. Turf technicians mowed to 1 inch height and recycled clippings. They applied fertilizer at the rate of 1/2 pound of nitrogen per 1000 square feet per growing month and irrigated as needed to avoid wilt. No disease or insect problems occurred during the test period and they applied no pesticides. He measured wear stress by comparing the amount of healthy living tissue before simulated stress and 3 days after. The best in overall wear tolerance were Texturf 10, Texturf 1f, Tiflawn, Ormond and Tifway. Cultural practices that would increase wear tolerance are those that increase above ground biomass, and reduce the less succulent, more delicate tissue. These include: mowing at the maximum height recommended for the species, allowing moderate thatch accumulation up to 1/3 inch, fertilizing with modest nitrogen levels, increasing potassium levels, irrigating modestly and infrequently. Modest levels of nitrogen sustain green color and leaf and root growth but do not deplete carbohydrate reserves by excessive growth. You can improve wear tolerance by increasing sun (reducing shade) in heavily trafficked areas. Shaded turf reduce tillering and biomass, and also have more succulent, delicate tissues. |
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