Healthy soils: The backbone of productive, safe and sustainable urban agriculture

The increasing urbanization of an ever-growing global population is coinciding with major global challenges that are threatening our food security. Urban agriculture is as a multi-functional tool to improve urban living and to provide food security towards resilient communities. This review explores on the importance of urban agriculture and identifies several points that will help inform a shift towards actively managed urban agriculture soils. First, the importance of soil within urban agriculture systems is highlighted, followed by a review of common issues of soil health in urban agriculture. These issues are then addressed by providing management principles for increased soil functioning in urban agriculture systems. These principles focus on improved soil nutrient and carbon pools and acknowledge the importance of the soil microbial community. Soil contamination with metal, organic and microbial contaminants is then addressed through a discussion of options available to help mitigate potential risk factors. Together, this review summarises our current understanding of soil health in urban agriculture systems. Where issues have been identified, these have been addressed by suggesting sustainable management principles. These can be used as recommendations for urban farmers towards more sustainable food production. Finally, we propose educational and governance approaches to help implementing these measurements.