I've been playing this game for quite a while now, and I've realized that I've never seen a planetary bonus that directly affects economy. I've seen research, population, influence, manufacturing and morale bonuses, but have never seen an economy bonus on planet. Now you could argue that the food bonuses affect economy by increasing population, and therefore your tax base, but that is an indirect effect. If it's not in the game, maybe it's something we can add to the wish list.