Hairy-vetch mulch does all of those things, too, but using it is not as convenient as laying down a few sheets of plastic, and is more expensive.

ECONOMIST: Genetic technology supports sustainable farming

On the other hand, plants grown using hairy-vetch mulch are a lot healthier (and yields are 20% higher), so Dr Mattoo wondered if he could track down the biochemical origins of this healthiness.

ECONOMIST: Genetic technology supports sustainable farming