Notice of said sale shall be given in the manner provided in such mortgage or deed of trust or in this Code in the county where the mortgagor resides and the land, or a part thereof, is located; but, if said mortgagor does not reside in the county where the land or any part thereof is located, then such notice must be published in the county where said land, or any material part thereof, is located; provided, that notice of all sales under powers of sale contained in mortgages and deeds of trust executed after July 1, 1936, where the amount secured is $500.00 or more, shall be given by publication once a week for three successive weeks in some newspaper published in the county in which such land or any portion thereof is situated, and said notice of sale must give the time, place and terms of said sale, together with a description of the property to be sold.