Do I mulch my tomato plants?
High-quality woven polypropylene landscape fabric, such as is used on greenhouse floors, is an excellent, porous, weed-preventive measure for a tomato patch. It can be reused for many years. Staple it to the ground with earth staples. On top of that, a layer of clean straw or some other organic mulch will further reduce splashing of spores and other woes up from the soil onto the plants.
Just have a few plants or a single row and the fabric would be overkill? The straw or equivalent alone will suffice.