Site Selection for Application of Compost to Golf Course Fairways Guided By Inherent Soil Properties.

Inherent soil properties can vary widely across landscapes and influence the effect of soil management practices such as compost application. Joint Base Lewis-McChord (JBLM) is a military base located near Tacoma, WA that produces compost (Earthworks) as a means for waste diversion and cost savings. JBLM's Eagles Pride Golf Course is implementing an Integrated Pest and Environmental Management Plan that includes the application of Earthworks compost to golf course fairways. A two-year experiment to assess the effects of compost application on soil and turfgrass quality parameters is underway. To account for different inherent soil properties across the 459-acre 27-hole golf course, 17 transects were established including 152 geo-referenced points. Soils at each location were analyzed for soil chemical and physical parameters.  As an example, percent sand ranged from 73.98 to 97.49, centimeters of organic matter from 1 to 7.7, and percent clay from 0.28 to 8.21.  To choose sites for the compost application experiment we used a priority and ranking algorithm that combined five of the geo-referenced sites into a soil “window”.  Associated with each window were the soil and chemical parameters collected from the geo-referenced sites.  Percent sand, percent clay, organic matter depth and pH were the factors fed into the algorithm.  Each factor was averaged for a particular window, ranked versus all other windows and then summed across the four factors.  Matches across all four factors were considered viable sites.  Final site choice was made with the intent to reduce the coefficient of variation.  The experiment is a three factor split-split plot design with fertilizer as the main plot, sand as the sub-plot, and compost as the sub-sub plot.  It is repeated three times on three sites.