Precolumbians - which could not obtain imported foods - must have been self supporting until the Europeans destroyed their societies. Today Peru has to import a large proportion of its basic food. With rapid increasinng population, the gap existing between the needs and the productions may soon become a subject of serious preocupations for the authorities. In view of remeding the problem that must be discussed by various experts in agronomy annd economy, the author - an expert or Aandean Culture - propose looking into the past and divulge information about precolumbian ecologies. In a few words, bis objectives are to acquire more data about subjects ubich can shortly expressed in a few words. Where, what, how and in what quantities did the Andeans gather, and later, produce fod, and how many people could their farming activities support?.