Comparative Soil Health in Urban Agrofrestry: A Case Study on Detroit's Perennial Agriculture Sites

Urban ecosystems are being intentionally developed to enhance innovation and resilience, addressing various community needs. Urban agriculture, particularly, involves cultivating food on soils affected by industrial activities. Urban agroforestry serves as a strategy to generate ecosystem services while increasing the availability of regionally adapted fruit and nut trees. Unlike annual crop production, agroforestry initiatives require less extensive soil management and labor, which can in turn enhance soil health. This case study examines soil health indicators—physical (bulk density), chemical (soil organic matter fractions), and biological (microbial diversity)—in one young urban food forest compared to two older conventional urban orchards in Detroit, MI, USA. Soil samples from cultivated fruit and nut perennials and their managed alleyways within the three agroforestry systems were analyzed at independent soil health labs. Preliminary findings indicate that mean bulk density was significantly higher in managed alleyways compared to agroforestry systems. Additionally, there are larger pools of total carbon and nitrogen in mineralized organic matter than in particulate organic matter across the study sites. Furthermore, microbial communities are more prevalent in the agroforestry systems than in their alleyways. The continued ongoing analysis aims to compare the soil health of the young urban food forest with that of the older urban orchards over time. Overall this study offers initial results to understand how longterm perennial agriculture can benefit soil health in urban systems.