A homestead to the extent of one hundred and sixty acres of farming land, or of one acre within the limits of an incorporated town or city, occupied as a residence by the family of the owner, together with all the improvements on the same, shall be exempted from forced sale under any process of law, and shall not be alienated without the joint consent of husband and wife, when that relation exists; but no property shall be exempt from sale for taxes, or for the payment of obligations contracted for the purchase of said premises, or for the erection of improvements thereon: Provided, That provisions of this section shall not apply to any process of law obtained by virtue of a lien given by the consent of both husband and wife: And provided further, That the legislature by an appropriate act or acts, clearly framed to avoid abuses, may provide that when it is shown the husband or wife while occupying a homestead is adjudged to be insane, the duly appointed guardian of the insane spouse may be authorized to join with the sane spouse in executing a mortgage upon the homestead, renewing or refinancing an encumbrance thereon which is likely to cause its loss, or in executing a lease thereon authorizing the lessee to explore and produce therefrom oil, gas, coal, lead, zinc, or other minerals.