If you are using a modded map, the textures may need to be placed within that specific map's folder rather than the base game files. Straw Mechanics in FS19
Ground Textures 30 V3.0 - FS19 Mod | Mod for Farming Simulator 19
Most users find this mod through community portals like LS Portal . Because it is a texture replacement:
It can be collected loose with a loading wagon or pressed into bales using a baler for easier storage and sale at the "Barn" sell point.