Constructing (multi)functional soil using urban organic and sediment wastes

Abstract As urban populations grow, planners must create sustainable, yet multifunctional city spaces. Urban soils are vital for green city initiatives, providing essential ecosystem services. Our research challenges the unsustainable practice of land-take and explores constructing (multi)functional soils from mineral and organic parent materials of the urban waste stream. We stack different qualities of organic amendments in innovative mixtures constructed of upcycled mineral soils from local construction projects to assess their potential in maximizing multiple ecosystem services within a constructed soil. Using key soil health indicators, we identify synergies for the parent material mixtures providing essential functions for urban soils: fertility for urban green, runoff infiltration, stormwater contaminant immobilization and stable carbon accrual. The highest joint multifunctionality is obtained by mixing organic amendments of varying qualities and reactivities. Soil-designing practitioners should be knowledgeable of their city’s regional geology, as the effectiveness of amendment mixtures depends on interactions with the geogenic materials.