Close. "Heimemark" are the cultivated areas closest to the farm. "Enclosed pasture" is just one suggestion, but it's not one I'm happy with, especially with this being a marketing text and the areas themselves may not necessarily be enclosed . "Farmland pastures" is in many ways better, even if it doesn't maintain the distinction between utmark and innmark. Hopefully someone with more farming knowledge will chime in.

infields, enclosed fields, home fields: taken from Theodore Slette's no-en dictionary, adding to the general enlightenment.