Sand-based turfgrass root-zone modification with biochar

Abstract

<p>Sand-based turfgrass root-zones are limited in nutrient retention and water holding capacity. Peat moss is often used to offset these deficiencies, but peat moss is prone to decomposition. Biochar, a co-product of the fast pyrolysis process used to produce bio-oil, may have similar benefits as peat moss while being less prone to decomposition. In addition, because biochar is relatively stable over time, sand-based turfgrass ecosystems established with biochar may become a viable long term carbon sequestration vehicle. At field capacity, sand-based media containing 25% biochar retained 63 and 73% more water compared to media containing 5% biochar and a pure sand control, respectively. Sand media containing 25% biochar resulted in a saturated hydraulic conductivity (Ksat) of 6.6 cm hr-1, whereas, 5% biochar media and pure sand resulted in Ksat of 55.9 and 84.8 cm hr-1, respectively. The rooting depth of bentgrass was reduced up to 46% at biochar concentrations greater than 10%. Leachate electroconductivity increased from 1.5 mmhos cm-2 to 3.4 mmhos cm-2 and dissolved total organic carbon increased from 20 ppm to 340 ppm as biochar concentrations increased from 0 to 25%. Leachate nitrate and ammonium concentrations decreased from 5 ppm to 0 ppm and 0.8 ppm to 0.2 ppm, respectively, as biochar concentrations increased. Soil phosphorus and potassium increased from 0 ppm to 118 ppm and 21 ppm to 892 ppm, respectively, as biochar concentrations increased.</p>