Root Zone Organic Matter Effects on Creeping Bentgrass Growth in Controlled Environments

This research evaluated the effects of root zone organic matter on creeping bentgrass growth in controlled environments. Refer to the abstract below presented as in the originally published HortScience journal article - Turfgrass growth resulting from soil organic matter (SOM) mineralization in putting green root zones has been explored sparingly. Glasshouse and laboratory studies were conducted in Knoxville, TN to discern if SOM content would result in differential mineralization affecting (CBG; Agrostis stolonifera L.) growth. Cores (10.8-cm width by 10-cm depth) were collected from CBG putting greens varying in SOM content: low (6.4 g kg -1 to 12.6 g kg -1), medium (12.7 g kg -1 to 19.4 g kg -1), and high (19.5 g kg -1 to 25.6 g kg -1). One putting green from each SOM group was selected for further investigation. After eight weeks, SOM decreased 5 g kg-1 within cores originating from putting greens in the high and medium SOM groups, compared to only 1 g kg-1 for those in the low SOM group. Inorganic N within cores from putting greens in the high and medium SOM groups increased more than those from the low SOM group, suggesting a greater percentage of inorganic N was allocated for CBG growth. When incubated at 25 °C under dark conditions, inorganic N increased 36 mg kg-1 in cores from the high SOM group, indicating the potential for as much as 50 kg ha-1 of N to become available within the root zone. If unaccounted for when making synthetic fertilizer applications, available N on CBG putting greens could lead to excessive growth under field conditions requiring additional maintenance practices. Future research to confirm this response under field conditions is needed.