(case involved whether tracts at issue should be classified as “agricultural” under Minn. Stat. §273.13 so that it is eligible for “Green Acres” treatment; court holds that property fails to qualify because tracts at issue comprise less than statutory minimum 10 acres; while petitioners owned three tracts totaling over 14 acres, residence located on parcel of almost 10 acres; residence parcel had over five acres that were not being used for agricultural production and balance of other two tracts had only three acres that were in agricultural use; vacant land not being used for agricultural purposes).