Top-dressing biochar enhances tree growth and decreases sodium leaching in greenhouse experiment
Session Number
Project ID: ENVR 3
Advisor(s)
Dr. Meghan Midgley; Morton Arboretum
Discipline
Environmental Science
Start Date
22-4-2020 9:10 AM
End Date
22-4-2020 9:25 AM
Abstract
De-icing salts on roadways are nearly ubiquitous in northern cities during the winter, leading to contamination of the soils adjacent to roadways. These salts (mostly NaCl) often have detrimental impacts on the flora exposed to them, though some species are more sensitive than others. Biochar’s large surface area relative to its volume allows biochar to “grab” onto salt, potentially limiting the amount of salt absorbed by plants or leached from the soil. We conducted an 8-week greenhouse experiment to test if biochar (applied either as a top-dressing or mixed into soil) mitigated salt’s negative effects on tree seedling growth & physiology and decreased sodium leaching. Given that biochar is relatively expensive, we also evaluated salt addition and biochar effects on four tree species that vary in salt tolerance: Catalpa speciosa (tolerant), Acer saccharum (intolerant), Gleditsia triacanthos (tolerant), and Quercus rubra (intolerant). We found no impact of salt addition on seedling growth, and salt addition did not significantly increase Na leaching until the experiment’s final weeks. However, there were differences in different species’ growth rates and biochar’s effects on growth rates. Trees that received a top-dressing of biochar acquired more below-ground biomass than trees with biochar mixed into the growing medium.
Top-dressing biochar enhances tree growth and decreases sodium leaching in greenhouse experiment
De-icing salts on roadways are nearly ubiquitous in northern cities during the winter, leading to contamination of the soils adjacent to roadways. These salts (mostly NaCl) often have detrimental impacts on the flora exposed to them, though some species are more sensitive than others. Biochar’s large surface area relative to its volume allows biochar to “grab” onto salt, potentially limiting the amount of salt absorbed by plants or leached from the soil. We conducted an 8-week greenhouse experiment to test if biochar (applied either as a top-dressing or mixed into soil) mitigated salt’s negative effects on tree seedling growth & physiology and decreased sodium leaching. Given that biochar is relatively expensive, we also evaluated salt addition and biochar effects on four tree species that vary in salt tolerance: Catalpa speciosa (tolerant), Acer saccharum (intolerant), Gleditsia triacanthos (tolerant), and Quercus rubra (intolerant). We found no impact of salt addition on seedling growth, and salt addition did not significantly increase Na leaching until the experiment’s final weeks. However, there were differences in different species’ growth rates and biochar’s effects on growth rates. Trees that received a top-dressing of biochar acquired more below-ground biomass than trees with biochar mixed into the growing medium.