An aqueous fluid irrigation system for protecting a region of a subsurface irrigation tube from root or microbial mass intrusion, comprising a porous cover covering a subsurface irrigation tube, wherein the cover essentially covers the region of the tube surface, and wherein the cover comprises a non-plexifilamentary material characterized by a peak void volume of less than 35 microns, and any planar region of the non-plexifilamentary material of an area of 500 square microns or less contains a contiguous polymer structure that remains contiguous when exposed to aqueous fluid.
