Incorporating biochar into urban agroecology

View the project final report

Commodities

• Agronomic: buckwheat, peas (field, cowpeas)

Practices

• Crop Production: drought tolerance, fallow, intercropping
• Education and Training: extension
• Natural Resources/Environment: soil stabilization
• Pest Management: physical control
• Soil Management: soil analysis, soil microbiology
• Sustainable Communities: urban agriculture

Given that 81% of the US population lives in urban areas (2010 census), urban agriculture represents a key sector for increasing food security and improving quality of life for urban communities. However, urban soils often pose issues that limit agricultural productivity: including compaction (~50%), high pH (~8), and contamination with heavy metals (Lead, Arsenic) caused by hotspots of industrial activity and unregulated waste, often at concentrations definitively toxic to humans. This is especially true in Detroit, where, for example, 4 neighboring oil refineries have created the most polluted zip code in Michigan. As a result of uniquely severe soil issues like these, urban farmers, such as those in Detroit, often need to import topsoils and/or compost, which can be prohibitively costly, but is often the sole option for soil remediation due to city-level regulations on maximum urban compost pile sizes. Ultimately, importing organic soils does not represent an ideal nor feasible strategy for the sustainability of crop production by urban farmers. This project addresses urban soil compaction and contamination issues by evaluating the effects of biochar application, alongside legume mixtures, on soil structure, nutrient retention, soil biological activity, and vegetable yield.

To complete this project, we will need to hold training workshops (with participation by at least 10 affiliated farmers, and others welcome) for aggregate mass distribution profile data collection, as well as data collection involving invertebrate identification. These training workshops will be related to general education in local soil ecology, as well as a platform for building community around agriculture. Ultimately, from this project, peer-reviewed publications and educational articles will be written about biochar’s effects on (1) soil aggregate mass distribution scaling parameters in combination with a tailored mechanistic model of soil aggregation, (2) nutrient concentrations in different soil aggregate mass fractions, (3) microbial community composition variation by soil aggregate mass, and (4) invertebrate community composition and diversity in bulk soils. These articles will also be reviewed in part and distributed to local community members, which will serve as lasting material of their own participation in academic research about their community.

To evaluate the impacts of our outreach events, we will conduct post-instructional and data analysis workshop surveys of farmers’ willingness to adopt biochar as a consistent and feasible soil management strategy, as well as synthesize statements on what they learned. In later years, we would also ask previous participants to lead workshops on soil aggregate and invertebrate data analyses for new and returning participants.