Development of Sustainable Urban Agricultural Practices in Arequipa, Peru

Agriculture in the city of Arequipa, Peru faces many stressors, including urbanization, mining and industry, water stress, and problems with regulation and oversight. Arequipa is located at 2300 m and is classified as a desert climate, with precipitation predominately occurring during the rainy season from December - March. Little is known about if and how much contamination exists in the urban agriculture throughout the city, although locals are very concerned about possible contamination of their fields and water from nearby mining. Additionally, agriculture in the city is irrigated with water from the Chili River, which runs through the middle of the city and provides valuable water in a region where water stress is common. Wastewater treatment is limited and often domestic and industrial effluent enters the river untreated as it passes through the city, causing potential risk to downstream agroecosystems that use this water for irrigation of vegetable crops. We completed synoptic sampling of the surface water network that is used for irrigation and soil sampling from farms throughout Arequipa. We measured concentrations of organic carbon, nutrients, and metals and completed respiration and carbon bioavailability assays. While physico-chemical properties varied, there was a distinct signature of urbanization that increased downstream along the Chili River and hot spots from legacies of industrial contamination. Along with this initial sampling, we also interviewed farmers and local authorities to learn about their current and historic farming practices, water rights and scarcity issues, and perceived sources of plant stress and soil contamination. We will share stakeholder network maps that highlight the complexities of the relationships that affect sustainability of urban agriculture in water stressed regions of the world.