SportsTurf provides current, practical and technical content on issues relevant to sports turf managers, including facilities managers. Most readers are athletic field managers from the professional level through parks and recreation, universities.
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FIELD SCIENCE 10 SportsTurf | June 2015 www.sportsturfonline.com senescence, and gibberellic acid promotes cell elongation. It has been reported that plant hormones extracted from seaweed can stimulate the production of antioxi- dants, which scavenge free radicals and thus protect plant cells from damage. Humic and Fulvic Acids. These substances typically are derived from leonardite or "brown coal," and were named after A.G. Leonard, the first director of the North Dakota Geological Survey, in recognition of his work in this field. Benefits of these compounds include increased nutrient and water holding capacity of soils (i.e., increased cation exchange capacity), prevention or reduction in leaching of soil nutrients, chelators of organic molecules and min- erals thus making them readily available for plant root absorption, increase in enzyme and metabolic activity, and more. Seaweed Extracts. These naturally occurring products can contain phy- tohormones, amino acid and vitamins, mineral nutrients and other compounds that may affect plants in many ways. A pioneer in the study of humic acids and seaweed in the US is Dr. T.L. Senn, Emeritus Professor of Horticulture, Clemson University. His work dates back to the 1960s, and he published "Seaweed and Plant Growth" in 1987. Currently, Dr. Erik Ervin at Virginia Tech, and Dr. Roch Gaussoin of the University of Nebraska in Lincoln, have led the way on turf research in biostimulants and plant nutrition. Seaweed extracts, humic acids, amino acids and other products that facilitate a turf benefit either through plant hormone effects or by increase antioxidant levels have been shown in their research. Amino Acids. Amino acids are the building blocks for proteins and enzymes. Evidently, only the "L" form of these amino acids are assimilated by plants. In plants, these L-amino acids are reported to increase roots mass, acti- vate natural defense mechanisms, and enhance photosynthesis. For example, L-proline is an amino acid that has been shown to improve water-stress tolerance in plants. Microbial Inoculants. There has been an increased interest with includ- ing Bacillus sp. bacteria and other microorganisms in biostimulant prod- ucts to help with plant disease defense and nutrient availability. For example, mycorrhizae are fungal organisms that form a beneficial relationship with plant roots, essentially increasing the roots' ability to absorb water and nutrients. Other Compounds. Vitamins, pro- teins, various minerals, metabolites and more can be considered as biostimulants. For example, vitamin E, glutathione, beta-carotene and others provide ben- eficial antioxidant activity in plants. Salicylic acid, which is essentially aspirin, is used to improve plant resistance to diseases and various abiotic stresses. Example of promotional information for Knife Plus (Floratine Products Group; Collierville, TN).