A mat for plant cultivation comprises upper and lower portions of non-woven fibers, substantially all of which are preferably natural, biodegradable fiber; an intermediate layer of bi-laterally stable plastic mesh, of high strength relative to the non-woven fiber layers, is structurally joined to the fiber portions, as by needling. The mat includes seed, and may include fertilizer and/or water absorbing material. A method of soil improvement comprises providing a mat having upper and lower portions of non-woven fibers, substantially all of which are natural, biodegradable fibers, with an intermediate bi-laterally stable plastic mesh layer structurally joined to the non-woven fibers. The mat is placed on the ground, such as a bare hill, for initially diminishing soil erosion by water run-off, the mat being optionally seeded after placement. The mat provided may be placed on poor soil, and after plant growth, the plants and mat may be plowed under, optionally in a repetitive cycle, to improve the soil.
