Depends on how close the field was to the original house. I'm detecting the field by my house now. The signals are few and far between but I'm digging some interesting things....musket balls (miniballs), some copper rivits from harnesses, an old brass key, and an 1888 v nickel. If you dig all signals you'll probably find horseshoes and pieces of farm implements.
Hunting larges areas like fields is time consuming, but there's very few pieces of modern trash. Good luck!