Agree with above... if next year your whole garden is potatoes, what would you do the following year, not to put potatoes in the same space they were? Alternate years of growing potatoes? 30x50 is small scale (relative to farms), but still monoculture crops tend to attract all the diseases and pests that crop is prone to.
Think about doing some companion planting:
Beans, cabbage, corn, and horseradish all help potatoes grow better and improve the flavor of your potatoes when grown together.
Tansy, nasturtium, coriander, and catnip planted nearby repel Colorado potato beetle.
Interplant potatoes with lettuce, scallions, radishes, and spinach. All of these crops mature fast and will be harvested long before the potatoes are ready to harvest.