Influence of humic acid on water retention and nutrient acquisition in simulated golf putting greens

Abstract

Humic substances are frequently applied to creeping bentgrass (Agrostis palustris Huds.) on golf putting greens to improve turf health and are marketed to enhance nutrient acquisition and possibly aid in retaining water in drought prone environments, but information on the role of humic substances in increasing soil water retention is limited. Additionally, it is difficult to separate the beneficial effects of nutrients and other ingredients added to commercial humic formulations from the effects of the pure humic substance. In our study, pure humic acid, tannic and citric acids were added to simulated creeping bentgrass putting greens. The organic acids were applied at normalized carbon rates of 250 mg C per litre by watering solutions through an automated irrigation system. Volumetric water content (VWC) and irrigation frequency, shoot and root growth, and tissue nutrient concentration of the turf were measured. None of the organic acid treatments improved water retention in the simulated greens. The humic acid‐treated greens required more frequent irrigation than the untreated greens indicating that they were drying out more quickly. In addition, the addition of humic acid did not result in an increased tissue concentration of nutrients in the creeping bentgrass, top growth or dry shoot mass compared with the other treatments. However, creeping bentgrass root length was greater in the greens treated with humic acid compared with the untreated control.

Evaluation of humic fertilizers on a sand‐based creeping bentgrass putting green

“…In contrast, Van Dyke et al. (2008, 2009) found that applications of humic acid decreased soil moisture and shortened the time between irrigation. Soil nutrient concentrations ranged from 10.4 to 12.2 mg kg −1 , 45.8 to 56.7 mg kg −1 , 206.3 to 243.8 mg kg −1 , 1,894.5 to 2,205.9 mg kg −1 , and 3.9 to 5.2 mg kg −1 for P, K, Mg, Ca, and Zn, respectively.…”

Evaluation of Humic Fertilizers Applied at Full and Reduced Nitrogen Rates on Kentucky Bluegrass Quality and Soil Health

“…Changes in physical soil properties can be difficult over short-term studies and normally have a slow response to management changes [3,5]. However, these results are different from Van Dyke et al [36,59], who found that humic acid applications decreased soil volumetric water content and increased irrigation frequency. Although there were no changes in soil physical properties during this experiment, long-term humic fertilizer studies should be conducted to see if there would be any changes over a greater time period.…”

“…Creeping bentgrass 16% root mass [35] Creeping bentgrass 21% root length [36] Tall Fescue (Schedonorus arundinaceus (Schreb.) Dumort.…”

Evaluation of Humic Fertilizers on Kentucky Bluegrass Subjected to Simulated Traffic

“…Earlier research has explored the benefits of humic substances on turfgrass. Applications of humic products on creeping bentgrass (Agrostis stolonifera L.) increased root dehydrogenase activity, root growth and weight, physiological health, antioxidant concentrations, turf quality, germination rate, and percent cover [31][32][33][34][35][36][37][38][39]. Humic substances improved antioxidant concentrations, recovery or tolerance to heat injury, transplant quality, and root weight of tall fescue [Schedonorus arundinaceus (Schreb.)…”