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.

Biostimulants for Sustainable Management of Sport Turfgrass

“…Biostimulant research on turf grass is scarce compared to that carried out on agricultural crops [ 4 , 8 , 10 , 13 ]. Moreover, there is less published evidence from open-field experiments, and even less pertaining to thatch control-related problems [ 6 , 17 , 18 ]. The objective of the present study aimed at evaluating the efficacy of a commercial product, EM-1, as well as two biostimulant products (ExpA and ExpB), developed by the present research group, on the widely used temperate turf species Agrostis stoloniferous L. Given that field trials provide essential information about biostimulant effects under real-world conditions [ 29 ], the experimentation was conducted under open-field conditions, with the aim of improving the characteristics of the plant rhizosphere, whilst simultaneously ensuring improvements to the plant, an aspect considered necessary in turf management.…”

“…Significant improvements included increased chlorophyll synthesis and resultant visual quality (DGCI), important for turf aesthetic standards [ 20 ], as well as increased resistance to tearing out in comparison to the control after the 56-day experimental period. Of great relevance, the inclusion of humic acids and mycorrhizal fungi to the microbial composition in ExpB significantly improved the plant rhizosphere, which remains an area warranting further investigation [ 6 , 17 , 18 ].…”

“…Hence, biostimulant-based improvements to the plant rhizosphere, in accordance with regulation (EU) 2019/1009 [ 11 ], would necessitate the increased degradation of organic matter and improved humification. In recent years, more attention has been focussed on controlling thatch in turfgrass [ 14 , 15 , 16 , 17 , 18 ]. Creeping bentgrass ( Agrostis stoloniferous L.), the most widely used cool season turfgrass on golf greens, is a potent producer of thatch, composed of intermingled living and dead plant tissue [ 19 ] formed from excess organic matter build-up (predominantly in the form of stolon development) and slow decomposition rates.…”

“…Moreover, commercial humic acid-based biostimulants have, similarly, been shown to positively impact root length, surface area, root volume, biomass and viability on both perennial ryegrass and creeping bentgrass [ 26 , 27 ]. Regarding thatch control and associated problems, there is very little published evidence pertaining to the effectiveness of biostimulants, and more work is required in this area [ 15 , 16 , 17 , 18 ].…”

“…Given the increased importance in innovative new technologies [ 4 ] and the requisite for more open-field investigations to confirm the efficacy of biostimulants in the environmental management of sport fields [ 1 ], especially with regard to thatch-associated problems [ 17 , 18 ], the present study aimed at addressing these aspects. Using both a commercial EM-1 product, as well as two additional innovations, the present study evaluated the efficacy of using Agrostis stoloniferous L. in the open-field on a golf green.…”