Optimizing Laccase Application to Facilitate Biodethatching.

One major problem in management of turfgrass greens is the accumulation of high organic matter content in the form of thatch and mat layers causing primary and secondary problems such as decreased movement of oxygen through the thatch or mat zone, decreased saturated hydraulic conductivity, and increased water retention in the thatch zone. Cultural practices like core aeration, vertical mowing, and top dressing that have been used to manage the thatch buildup are intensive in terms of cost, energy, and labor as well as have adverse effects on turfgrass quality. The rate of thatch degradation is limited by lignin, a plant cell wall constituent that is resistant to microbial degradation and limits the availability of easily degradable cellulose and hemi-cellulose to the microbes. Degradation of lignin in the environment in carried out by certain white-rot fungi which degrade lignin with the help of lignolytic enzymes. We developed a novel approach in which we used fungal laccase, a lignolytic enzyme, from Trametes versicolor, to facilitate lignin degradation and in turn manage thatch. In 2010, a field study was conducted on a bentgrass green to optimize the rate and frequency of laccase application. Laccase was applied at five activity levels of 0, 0.5, 1.0, 2.0, and 4.0 units cm^-2 at frequency of two weeks and treatment 2.0 units cm^-2 of laccase activity was applied at four frequencies of 2, 4, 8, and 12 weeks. Significant reduction in thatch, lignin content, and structural sugars was observed after six months of treatment application. No adverse effect on turf quality was observed by laccase application.