Residual Effect of Laccase Application On Thatch Layer Characteristics of Creeping Bentgrass.

Organic layer formation in the form of thatch is one of the major problems in turf management systems. Bi-weekly application of laccase enzyme has been well documented to facilitate the degradation of thatch layer and reduce the rate of accumulation of organic matter in “Crenshaw” creeping bentgrass (Agrostis stolonifera L.). A field experiment on creeping bentgrass was conducted to observe the residual effect after ceasing laccase application. The experiment consisted of twelve treatments partitioned into sub studies to investigate: different activity levels (rates); frequency; sources of laccase; and its application with cultural management practice i.e. core aeration and sand topdressing. Laccase treatments were applied for six months and response to residual laccase effect was recorded by sampling at six, twelve, and eighteen months after treatment initiation. One of the twelve treatments was applied for six months in year one and for six months in year two to compare the residual effect of laccase with two year laccase application. Parameters investigated were thatch layer thickness, total organic matter (0-2.5 cm, 2.5-5.0 cm, and 0-5.0 cm depth), saturated hydraulic conductivity, and acid-soluble and-insoluble lignin. A significant reduction in thatch layer thickness was observed with laccase at different rates and frequencies at six, twelve, and eighteen months after treatment initiation. Residual effect of laccase was observed in thatch layer depth with no accumulation in after six months of treatment cessation. A significant increase in thatch layer was observed at eighteen months after treatment initiation in plots where application ceased after six months and no accumulation was observed in plots treated with laccase for six months once a year.