Where any condemner shall have taken or attempts to take property for public use, the damages for taking such property shall be determined according to the laws of this state irrespective of whether the condemner may be reimbursed for a part of such damage from the federal government and such damages shall include all compensable damages suffered by the condemnee including but not limited to reasonable severance damages and condemnee’s abstracting expenses. In determining the amount of such severance damages, account shall be taken, together with other relevant factors, of the economic effect, if any, caused by the severance therefrom of the part taken or sought to be taken upon the whole of such property as a going concern as it will be and remain after the severance. Any decrease or increase in the fair market value of real property prior to the date of valuation caused by the public improvement for which such property is acquired, or by the likelihood that the property would be acquired for such improvement, other than due to physical deterioration within the reasonable control of the owner, shall be disregarded in determining the compensation for the property. The provisions of this section shall apply to any case now or hereafter pending.