Golf Course Management

OCT 2018

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66 GOLF COURSE MANAGEMENT 10.18 minimal amount of particulate organic car- bon, likely because the sand collection and handling process might have weakened the attachment between the organic coatings and sand. OARS or pHAcid removed the same amount of particulate organic carbon from sand columns as the water control (Figure 3B). Treatment with Matador, however, re - moved 6.9 times the amount of particulate organic carbon as water alone. Based on the type of filter we used in this experiment, the particles we collected to determine the par - ticulate organic matter were finer than 0.05 mm, which classifies the organic carbon we removed as fine particulate organic carbon. It has been reported that, even when present at a low concentration, fine particulate organic carbon significantly increases soil water repel - lency (3). erefore, our results suggest that application of Matador followed by three se - quential washes removed a substantial amount of water-insoluble organic coatings from the sand columns, which likely contributes to an improvement in wettability of the sand. Treatment effects on soil water repellency e solid phase organic carbon in the wa- ter-only treatment remained statistically con- stant compared to the amount of solid phase organic carbon found in the same source of sand that was not treated. Sands treated with pHAcid showed a 16% reduction in solid phase organic carbon compared to the sands that were not treated. Compared to the un - treated sands, those treated with Matador resulted in the same amount of solid phase organic carbon, while application of OARS produced 27% greater solid phase organic car - bon. is intriguing result suggests that ap- plication of OARS introduced an additional source of organic compounds to the sand pro - file, and these organic compounds remained in the sand system in a solid form. is result again suggests a strong sorption of the OARS molecules to the sand, corroborating the find - ings on the dissolved organic carbon as de- scribed above. After application of treatments and three washes, sand treated with pHAcid showed no change in its hydrophobicity compared to the water-only treatment (Figure 4). In contrast, application of OARS significantly reduced the hydrophobicity of the sand to the category of low water repellency. Application of Matador completely reversed the hydrophobicity of the sand and resulted in a wettable sand. Conclusion Collectively, results from this research indicate that both OARS and Matador are promising for reducing soil water repellency to a minimum (OARS) or zero (Matador), fol - lowing one application and three sequential washes. Although the reasons are not fully understood, our data suggest that OARS molecules exhibit strong sorption to the hy - drophobic sand surfaces, and a significant amount of the molecules likely remain in the sand system despite sequential washes. In comparison, applying Matador may wash out a greater amount of organic compounds from the system in both water-soluble and insoluble forms. Our results also suggest that deep irri - gation following application of wetting agents such as Matador likely increases removal of organic coatings from the sand profile. How - ever, caution is needed because this is strictly a laboratory-based experiment, and implica - tions for field conditions could be complicated as plants, soil and microorganisms interact. e research team at the University of Missouri has been performing more in-depth laboratory and field experiments in this line of research, so stay tuned for more research findings. Acknowledgments is material is based on work that is sup- ported by the National Institute of Food and Agriculture, U.S. Department of Agriculture, under award number 1006256 to principal in - vestigator Xi Xiong. e authors would also like to thank the United States Golf Associa - tion for funding. Literature cited 1. Dekker, L.W., K. Oostindie and C.J. Ritsema. 2005. Exponential increase of publications related to soil water repellency. Australian Journal of Soil Research 43:403-441. 2. Dunkelberg, E., U. Boeckelmann, B. Braun, D. Diehl, G.E. Schaumann and E. Grohmann. 2006. Do wax- degrading bacteria influence water repellency of soil? In: First International Biohydrology Conference, Prague, Czech Republic, Sept. 20–22, 2006. Figure 4. Effect of treating soil-repellent sand with one of two wetting agents, a surfactant, or deionized water, followed by three sequential washes. Soil water repellency was determined by using the molarity of ethanol droplet test. Bars labeled with the same letters are not significantly different. c b a a Treatment Molarity (M)

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