Master of Science / Department of Horticulture, Forestry, and Recreation Resources / Jared Hoyle / Buffalograss [Buchloe dactyloides (Nutt.) Engelm] is a warm-season turfgrass species that is native to North America and requires minimal maintenance to survive. However, the use of buffalograss on golf courses throughout the transition zone is limited due to its appearance, growth habit, and lack of information available. Buffalograss is more drought tolerant than many other turfgrass species cultivated on golf courses, therefore, its drought resistance can lead to significant water savings. The objectives of these 2014 – 2016 field research studies were to evaluate: 1) buffalograss divot recovery as influenced by nitrogen source and application rate; 2) the influence of nitrogen application rate and simulated golf cart traffic on the wear tolerance of buffalograss; 3) the effect of simulated golf cart traffic on colorant treated buffalograss; and 4) buffalograss recovery from winter trafficking. When compared to untreated turf, divots in buffalograss treated with urea achieved 50% divot recovery 6.3 days faster when 1 lb N/1,000 ft² was applied, which was statistically similar to the 3 lb N/1,000 ft² rate. Applications of a slow-release polymer coated urea did not enhance divot recovery duration when compared to untreated turf. As nitrogen application rate increased in the presence of traffic stress, regardless of traffic rate, the green cover, quality, and color of the turf was enhanced. Percent green cover values for 0, 1, 2, and 3 lb N/1,000 ft² 10 weeks after initiation (WAI), regardless of traffic rate, were 60.2%, 69.0%, 75.5%, and 79.1% respectively. Regardless of nitrogen application rate, buffalograss receiving 16 passes/week of traffic never provided >72% green cover, while buffalograss receiving 0 passes/week had 74% green cover prior to the onset of dormancy. Endurant Premium turfgrass colorant in the presence of wear treatments provided >50% green cover 0 – 5 weeks after treatment in 2014 and 0 – 3 weeks in 2015. In general, as traffic rate increased, turfgrass colorant longevity decreased. Overseeded perennial ryegrass hindered buffalograss recovery after winter trafficking in comparison to untreated turf and colorant applications.

Geohumus is a new, unique hybrid soil amendment made of polyacrylic acid, igneous rock flour, and quartz sand. It is biodegradable and is marketed to increase soil porosity, increase plant yield, and increase plant available water by up to 30%, all while using a low inclusion rate of only 1 - 2% volume/volume (v/v). The objective of this research was to evaluate uses of Geohumus in a turfgrass setting. Two field trials and one greenhouse trial were conducted between the summers of 2010, 2011, and 2012. For the field incorporation study, Geohumus was mixed with USGA (United States Golf Association) specified sand and incorporated at a 1% v/v ratio into an existing perennial ryegrass stand maintained at two heights of cut using various incorporation machinery. Treatments included incorporation of Geohumus via an aerator, dethatcher, Graden, or simulated drill-and-fill. Daily light box pictures were analyzed using SigmaScan Pro software to compare percent green cover among treatments and to establish which plots were to receive irrigation. The readings showed significant differences among treatments in irrigation applications required to keep the turf green. The aeration treatment by itself was as effective as any treatment with Geohumus incorporation. Aeration provided a 35% reduction in irrigation applications on the 61 mm height of cut in 2011 and a 24% reduction in irrigation applications on the same height in 2012. The second field trial evaluated various soil amendments for use in divot repair mixes under full sun and partial shade conditions. In addition to differing microclimates, divots were further evaluated by receiving either one or two irrigation applications per day. Uniform divots with dimensions of 10.16 x 7.62 cm were created using a spring-loaded catapult with a hula-hoe attachment. Treatments applied consisted of combinations of United States Golf Association (USGA) specified sand and perennial ryegrass seed but differed according to soil amendments which were incorporated into the divot mixes based on volume (v/v). Soil amendments tested included Geohumus (1% v/v), Zeba (1% v/v), Axis (10% v/v), Lassenite ATS (10% v/v), Dakota Peat (10% v/v), Scotts EZ Seed (10% v/v), and Wondersoil (10% v/v). Weekly ratings were taken using light box pictures in conjunction with digital analysis software to measure percent green cover. Results indicated that microclimate and irrigation frequency affected the establishment of divot repair mixes more than the presence of soil amendments. A third trial comparing perennial ryegrass root masses grown in rooting boxes in a greenhouse showed major differences as influenced by placement of Geohumus within the soil profile. Geohumus influenced root mass in the upper 7.6 cm of the soil profile but no significant differences were found at lower depths. Geohumus incorporated at a 7.6 - 12.7 cm depth appeared to be the most influential depth for increasing root mass in the upper 7.6 cm of the profile. / Graduation date: 2013