Hannah Heyman

Hannah Heyman

Hannah Heyman

Speaker | Cornell University

Ithaca, NY | 914-924-2477 | hh624@cornell.edu

Hannah Heyman is a graduate student at Cornell University researching the use of compost for urban soil remediation. She is also working with Professor Nina Bassuk to create an amendment to the Cornell Soil Health Manual devoted to urban soil. Hannah has a background in public horticulture having previously worked at the Brooklyn Botanic Garden and Riverside Park Conservancy in New York City. She received her B.S. in environmental science at the University of Michigan.

Presentation Title: Creating a Comprehensive Compost Specification for Soil Compaction Remediation for the Urban Landscaping Industry

Session: Compost Uses and Markets: Expanding Opportunities

Time: Wednesday, January 30, 11:00 AM – 12:30 PM

Presentation Summary: One of the top challenges facing urban landscape managers today is soil compaction from construction,heavy foot and vehicle traffic. Soil bulk density in urban areas is often so high that plants are unable to access the water and nutrients they require to live. This often means money is wasted on plants that will die after only a few years or on shipping in topsoil mined elsewhere. The third option is remediating the existing soil on site. Research conducted by Miles Schwartz Sax and Nina Bassuk in 2015 concluded that effective, long term compaction remediation can be achieved by incorporating generous amounts of compost (about 33% by volume) into existing compacted soil on site. This method, designated, “Scoop and Dump,” after the action of the backhoe doing the mixing, not only improves bulk density and increases macroporosity over time, but also increases microbial activity and available water holding capacity in the soil.

My project is a continuation of this work to determine specifically what characteristics would define the ideal compost for the “Scoop and Dump” method and compose a specification.Composts were collected from all over New York State from different producers (e.g. private companies, municipalities, farms, universities) and made from a variety of feedstocks (e.g. cow, horse and poultry manure, yard waste and food waste). Composts were selected that covered a wide range of qualities like organic matter percentage, salinity and carbon to nitrogen ratio. A bioassay is being conducted with nine different composts at different concentrations in the soil (0%, 33%, 50%, 100%). Additionally, leachate has been collected from the pots in our bioassay at regular intervals. From this leachate we are measuring the levels of soluble reactive phosphorous, nitrate and ammonium that are being lost from each compost mixture in order to determine the risk of nutrient leaching for our final specification.

Urban soil has been given some much-deserved attention in recent months as a possible sink for greenhouse gases and as a first step to creating more livable cities overall. Using compost for on-site remediation will provide an opportunity for urban landscapers to save money and utilize locally sourced material. It will also provide a market for compost produced from the recent mandated diversion of organic waste in populated areas. A clear and comprehensive specification will be a vital tool in bringing these industries together.