A review of a novel enzyme system for the management of thatch and soil water repellency in turfgrass

Abstract

Managing soil organic matter is a crucial component of greenkeeping and turfgrass maintenance. Organic matter accumulation as thatch is a major problem in modern turfgrass management. Additionally, soil water repellency (SWR) caused by hydrophobic organic coatings on sand particles can create serious soil water infiltration and potential runoff problems and contribute to a reduction in turf quality and playability. Lignin is a major component of thatch and acts as protective matrix limiting microbial degradation of cellulose and hemi-celluloses. This article reviews lignin structure and its unique oxidation mechanism that makes it suitable for use in turfgrass systems and the research progress to develop laccase as a tool to manage thatch layer and SWR. A series of experiments explored the potential for direct application of fungal produced enzymes to degrade lignin, speed thatch degradation, and thereby reduce thatch accumulation. Greenhouse studies provided proof of concept and confirmed laccase impact on physical and chemical properties of thatch. Field studies verified the effectiveness of laccase application on different turfgrass species and optimized application rates and frequency. The reduction in thatch layer thickness by laccase treatments was similar to reductions achieved by cultural management and greater reductions occurred when applied in combination with cultural management. The use of laccase and other enzymes to ameliorate SWR was verified by a series of laboratory and field studies. Single applications of laccase were effective in reducing SWR but not as effective as wetting agents. Enzyme applications combined with a wetting agent to provide maximum relief of SWR. Application of laccase in combination with core-aeration and sand topdressing could reduce the number of mechanical cultivations necessary to keep thatch layers at desired levels and reduce the potential for SWR. Laccase could provide a nondisruptive organic approach to manage thatch and SWR on highly managed turfgrass.