What do urban agriculture projects do?

In a recent blog, Wayne Roberts mentions: "Producing food may well be the least accomplishment of urban agriculture, though that extra food can really make a difference for people on low income. But the crop itself is only one contribution on a long list that includes enhanced public safety, community vitality and cohesion, neighborhood place-making, skill development, food literacy, garbage reduction (through composting) and green infrastructure." Also RUAF director Marielle Dubbeling in her blog goes into the multi-functionality of urban agriculture and what city governments and private sector can do to further increase city sustainability.