Graduate Research Assistant University of Maryland
Deficiencies in essential organic matter (OM) are exhibited in disturbed roadside soils rendering them less favorable for plant growth. Vegetation plays a crucial role in maintaining the health of ecosystems, providing a myriad of benefits in protecting against soil erosion and managing stormwater effectively. Organic amendments (OA) are recycled and repurposed materials that serve as valuable soil conditioners. Previous research has raised concerns around the use of nutrient-dense organic materials (composts) due to excessive nutrient leaching, which may worsen the existing problem of stormwater pollution. On the other hand, some biochar amendments, particularly those made from wood waste, can lack plant-available nutrients (N and P) and may limit vegetation. This study takes a holistic approach to understand the synergistic effects of compost-biochar mixtures on physical and chemical behaviors of soils, water quality (N and P), and vegetation establishment. Biochar and compost amended soils are evaluated in a large mesocosm experiment with slope considerations, mimicking roadside embankments. The reference soil is deficient in OM below the range of 3-15% typical to many DOT topsoil specifications. To boost the OM content of the soil, compost (Y) produced from yard waste, and a wood-derived biochar (B) were amended. The media included a control soil, soil amended with Y, soil amended with B, soil amended with 75%Y and 25%B, and soil amended with 50%Y and 50%B. All amended soils targeted to reach a soil OM of 6%. Given the concerns of composts in terms of water quality and wood-derived biochar with respect to vegetative health, this study hypothesizes that a mixture of compost and biochar incorporated into soils can improve soil fertility, plant uptake of nutrients, and soil hydraulic properties, all while minimizing nutrient losses to infiltrated or surface waters.
