Biochar as An Organic Amendment Alternative in Sand-Based Turfgrass Sites or Golf Course Putting Greens.

Biochar is an organic matter byproduct of the low temperature pyrolysis of biomass with greater ability to retain nutrients than conventional organic amendments while being highly stable against decay.   Biochar was examined as an alternative to traditional organic amendments in sand-based root zones by monitoring the benefits to turfgrass establishment and growth and potential for nutrient loss through leachate.   Three soil mixtures consisting of either quartzite sand, sand mixed with biochar or sand mixed with sphagnum peat moss at a 90:10 (v v^-1) ratio were placed in free draining lysimeters.  Lysimeters were seeded with creeping bentgrass (Penn A-1, Agrostis stolonifera L.) at a rate of 98 kg ha^-1 and received fertilizer at a rate of 4.9 kg N ha^-1 or no supplemental fertilizer. Under greenhouse conditions, plots were mowed at 7 mm and irrigated three days a week to container capacity. Photos and quality measurements were taken weekly to monitor establishment rates and overall turf performance.  Bi-weekly leaching events were induced by bringing each lysimeters to container capacity, at which point 300 ml (9.25 mm) of irrigation was added to each plot to force leachate and monitor potential loss of nitrogen (N) and phosphorus (P).   Biochar plots with and without fertilization produced significantly denser turfgrass and overall higher visual quality assessments compared to respective fertility treatments of peat/sand and sand plots.  With the exception of one leaching event where sand and biochar leached significantly more N, leaching rates were similar for all fertilized plots and greatly diminished over time as turf density increased.   Phosphorous leaching was significantly higher for fertilized and unfertilized biochar plots across all time points compared to all other treatments. Biochar appears to be a potential organic amendment alternative to sphagnum peat moss to improve overall density and quality of establishing putting greens or sand-based turfgrass sites.