Vegetarian vs. vegan footprint?

i have seen several studies that calculated that the 'best' system is good old fashioned small mixed agrarian farming, with annual grains and veg, tree and other perennial crops, and permanent pasture in about equal amounts. the complete removal of animals causes problems for returning nutrients to the soil; one vegan system i have read about uses 60% of crop land for green manures. also there are many places unsuitable for tilling but suitable for either seasonal or year round grazing. but in the west now we eat far more meat than this would supply, so a big reduction in meat and dairy eating is called for. if half of us went veggie, there would be more for the rest of us :-D