Assessing the potential contribution of vacant land to urban vegetable production and consumption in Oakland, California

As urban agriculture grows in popularity, researchers are attempting to quantify its potential contribution to local food systems. We present the results of a vacant land inventory conducted in collaboration with the HOPE Collaborative, a multi-stakeholder, community-based initiative in Oakland, CA, USA. Vacant lots, open space, and underutilized parks with agricultural potential were identified using GIS and aerial imagery. Using visual interpretation, we identified 1201 ac (486.4 ha) of public land and 337 ac (136.4 ha) of private land that could potentially be used for vegetable production. Based on USDA loss-adjusted consumption data, we calculated the potential contribution of these sites to the city's current and recommended vegetable needs. Calculations were based on average yields under three different management practices: conventional at 10 tons/ac (22.4 Mg/ha); low-biointensive at 15 tons/ac (33.6 Mg/ha); and medium-biointensive at 25 tons/ac (56.0 Mg/ha). Four different land use scenarios were considered: (1) all identified sites (<30% slope); (2) optimal land (<30% slope excluding north-facing slopes); (3) a high land use scenario of 500 ac (202.3 ha); and (4) a low land use scenario of 100 ac (40.5 ha). We estimate that the most conservative scenario would contribute between 2.9 and 7.3% of Oakland's current consumption, depending on production methods, or 0.6-1.5% of recommended consumption. While an inventory is an important first step, determining how much vacant land should be committed to urban agriculture will ultimately depend on additional site assessment and negotiation of potentially conflicting stakeholder interests. (C) 2012 Elsevier B.V. All rights reserved.