Let me clairfy something I learned in my ethnobotany classes and many field trials. These books show a pretty line drawing or coloured illustration that is the envy of a fast food promotional campaign.People who are intimate with their local plants, are most often hunter gatherers or a culture recently moved on, but retaining that knowledge.These people had something in abundance, even in apparently hostile climes. They had time, lots of it. You're right, some of these plants are very labour and water intensive. I hope you caught a clue in that statement. Water intensive means you will have a whole lot of easier food sources besides something that looks like the latest asian vegetable fad.