University of Minnesota Extension Master Gardener CenUSA Biochar Demonstration Gardens 2012-2015

Abstract

Soil serves as the foundation of all gardens, and thus incorporating beneficial amendments before planting is of the utmost importance to a healthy, roductive crop. Increased interest and research in biomass and biofuels has promoted the use of biochar, a coproduct of the pyrolysis process, as one amendment to improve soil health. Urban soils, the site of many home and community gardens, can be carbon-poor, so we wondered if biochar would benefit home gardeners and grow more productive plants. Soils at four demonstration sites in Minnesota were amended with hardwood biochar. With the help of Extension Master Gardener volunteers, we grew, harvested and measured common garden crops over four years to see if those grown in biochar-amended soils were more productive. Variables in weather, crops and volunteer interpretation of data did not provide conclusive results. However, the poorer soils amended with biochar showed some increase in soil pH and percent organic matter, and clay loam soils were less compacted. Most crop yields showed improvement over the four years; however, we believe these increased yields were likely affected by a combination of factors (rainfall, air temperatures) and cannot be directly attributed to the addition of biochar.