Biochar-organic amendment mixtures added to simulated golf greens under reduced chemical fertilization increase creeping bentgrass growth

Simulated golf greens were used to test the growth of creeping bentgrass (Agrostis stolonifera L. '007') receiving suboptimal chemical fertilization in sand based substrates amended with 15% peat (control), a commercial biochar, a commercial biochar-compost mixture (CarbonizPN-Soil), or seven formulated biochar-compost mixtures. Physical and chemical properties including pH, bulk density, pore space, compaction distance, nutrient content and water/nutrient retention capacity varied among the mixtures. The heights, root lengths, and fresh and dry weights of creeping bentgrass plants grown in polyvinyl chloride tubes containing the different substrate mixtures mimicking a United States Golf Association root zone were evaluated and compared. Forty days after seeding, plants grown in 5% biochar and 10% Metropolitan Water Reclamation District of Greater Chicago biosolids had significantly greater fresh weights, dry weights, and shoot heights than the control. Dry weights and shoot heights were also higher than the control in bentgrass grown in the 15% CarbonizPN-Soil mixture. Based on these results the addition of these two biochar-organic amendment mixtures would improve overall plant growth in sand-based root zones under reduced chemical fertilization.