Physical and Mineral-Nutrition Properties of Sand-Based Turfgrass Root Zones Amended with Biochar

Sand-based turfgrass root zones have limited nutrient retention and water-holding capacity. Peat moss often is used to offset these deficiencies, but peat moss decomposes. Biochar is a co-product of several biofuel production processes used to produce bio-oil. Biochar is stable and could have similar water and nutrient retention impacts as peat moss when mixed in sand-based turfgrass root zones. The objective of this research was to evaluate the efficacy of biochar as a sand-based root zone amendment. Water retention, water infiltration, creeping bentgrass (Agrostis stolonifera L.) rooting depth, and nutrient evaluation experiments were conducted on six sand and biochar root zone mixtures. At field capacity, sand-based media containing 25% (v/v) biochar retained 260 and 37096 more water compared to media containing 5% biochar and a pure sand control, respectively. Saturated hydraulic conductivity (K-sat) of the root zones decreased as biochar concentrations increased. The rooting depth of bentgrass was reduced up to 46% at biochar concentrations > 10%. Extracted pore water electrical conductivity and dissolved total organic carbon increased as biochar concentrations increased. Nitrogen leaching was reduced as biochar concentrations increased. According to the results, biochar may improve water storage, reduce overall water use, and decrease N fertilizer applications in sand-based turfgrass ecosystems.