Patent ID: 8689484

Claim:
A sheet material for preventing entry of unwanted roots into a volume of soil, comprising a flexible carrier sheet of a non-biodegradable polymeric herbicide-absorbing material; discrete spaced-apart layered segments of a polymer containing a dinitroaniline herbicide positioned on an outer surface of the carrier sheet, leaving an uncoated exposed surface of the carrier sheet in between the spaced-apart layered segments, the layered segments comprising a composition effective to retain and control the release rate of said herbicide; the layered segments having outer surfaces coated with a layer of barrier material so that the layered segments block diffusion of the herbicide directly through said barrier material, to cause essentially all of the herbicide contained in the layered segments to be distributed away from the layered segments and laterally through the herbicide-absorbing carrier sheet, for ultimately dispersing the herbicide away from the uncoated exposed outer surface of the carrier sheet and into the soil at a controlled release rate.