Thesis (doctoral)--Swedish University of Agricultural Sciences, 2005. / Includes bibliographical references. Also available on the World Wide Web.

by Chu Lee Man. / Bibliography: leaves 176-204 / Thesis (M.Phil.) -- Chinese University of Hong Kong, 1983

Thesis (Ph. D.)--University of Hawaii at Manoa, 1995. / Includes bibliographical references (leaves 167-170). / Microfiche. / xx, 170 leaves, bound ill. 29 cm

Thesis(M.S.)--Auburn University, 2006. / Abstract. Includes bibliographic references.

Thesis (M.S.)--Oregon State University, 1999. / Typescript (photocopy). Includes bibliographical references (leaves 70-72). Also available on the World Wide Web.

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1997. / Title from PDF title page (viewed on Dec. 13, 2005). Includes bibliographical references.

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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