Golf Course Management magazine is dedicated to advancing the golf course superintendent profession and helping GCSAA members achieve career success.
Issue link: http://gcmdigital.gcsaa.org/i/95639
research the 20.6 units/square centimeter treatment appli- cation was discontinued. Laccase treatments were applied as a 1.35-ounce (40-milliliter) solution for each of the different activity levels, and the con- trol was applied as 1.35 ounces of distilled water. Guaiacol was applied as 0.34 ounce (10 millili- ters) of solution. Laccase activity assay The laccase enzyme used in the experiment was from Trametes versicolor, a white rot fun- gus (Sigma-Aldrich). The activity of laccase was quantified by a colorimetric assay using a UV/ VIS-spectrophotometer. The amount of laccase that causes an absorbance change at 468 nanome- ters at a rate of 1.0 unit/minute in 3.4 milliliters of 1 millimolar 2,6-dimethoxyphenol in citrate- phosphate buffer at pH 3.8 corresponds to one activity unit (9). Measurements Parameters used to determine the effective- ness of treatments were total organic matter con- tent for a depth of 0-2 inches (0-5 centimeters), saturated hydraulic conductivity, organic layer thickness, extractive-free acid-soluble lignin, acid-insoluble lignin and total lignin content after two months of treatment application. Total lignin content was obtained by addition of acid- soluble and acid-insoluble lignin contents. When sampled after nine months of treatment, organic layer thickness was subdivided into thatch layer thickness and mat layer thickness, while total organic matter content was subdivided into 0 to 1-inch (0- to 2.5-centimeter) depth and 1- to 2-inch (2.5-5 centimeters) depth to more accurately reflect the effectiveness of laccase on thatch layer thickness and organic matter reduc- tion in thatch layer. Organic matter content Two soil cores (0.78 inch [2.0 centimeters] in diameter) were dried in an oven at 212± 9 F (100±5 C) for 48 hours, weighed and ashed in a muffle furnace at 1,112±18 F (600±10 C) for 24 hours and weighed again. Total organic matter content was the difference in the two readings; percent total organic matter was calculated. Saturated hydraulic conductivity Intact cores 2 inches (5 centimeters) in diam- eter and 3 inches (7.6 centimeters) long were col- lected in the brass cylinders from the center of each pot using a soil corer. The saturated hydrau- lic conductivity of the cores was measured. December 2012 GCM 85 Cores were removed from pots and then tested for saturated hydraulic conductivity. Photos by Rashmi Singh The organic layer, thatch layer and mat layer of each pot were measured at seven different locations and averaged. v v