1. A plow bottom cover in combination with a plow bottom formed of a moldboard and share, a standard having its lower end attached to the rear face of said plow bottom, said plow bottom having a generally elliptical forward end portion along the moldboard and a generally pointed rearward end portion along the share, said cover comprising a flexible front sheet and a flexible rear sheet, said front and rear sheets each having preformed generally elliptical forward end and a preformed generally pointed rearward end corresponding to the configuration of the moldboard and share of the plow bottom, said front and rear sheets being connected together along their top, bottom, forward and rearward edges, said front sheet covering the entire front face of the moldboard and share, said rear sheet covering a major portion of the rear face of the moldboard and share including the entire outer circumferential rear face of the plow bottom and including the entire rear face of the share, said rear sheet having a central opening surrounding the attachment of the standard to the plow bottom, elastic string means on said rear sheet extending about said opening to draw said opening together to snugly attach said cover to said plow bottom, said opening being of a size whereby when said elastic string means are expanded said opening will be enlarged sufficiently to enable said cover to be detached from said plow bottom via said opening.