Humic substances are often used as an amendment in putting greens to improve turf health, but little is known regarding their effects on soil moisture retention. Commercial humic substance products and pure organic acids were applied to three golf course putting greens in Utah in 2006 and the Utah State University research putting green in 2006 and 2007. These treatments were evaluated for effects on soil volumetric water content, phosphorus uptake, and chlorophyll content of creeping bentgrass (Agrostis stolonifera L.). Three irrigation levels — 80%, 70%, and 60% — of reference evapotranspiration (ETo) were imposed on the turf at the research putting green. Humic substances did not increase moisture retention in putting green soils as pure humic acid significantly decreased soil volumetric water content compared to the control. Both humic acid and fulvic acid-treated plots had lower soil moisture content readings than the control at a depth of 4-6 inches (10-15 cm) during the growing season. Uptake of phosphorus by creeping bentgrass was significantly decreased with the application of humic acid, and no differences were observed for chlorophyll content of the turf with any humic substance treatment. While they may provide other benefits, humic substances may not provide superintendents with benefits of reducing water or phosphorus
fertilizer on putting greens.
Read the peer reviewed article published in Applied Turfgrass Science Journal