Mulch

A material applied to a surface to help in retaining moisture within a soil profile, to improve soil organic matter and micro-biological content and activity, to suppress weed seed germination, as well as improving soil fertility and also to reduce soil erosion. The return of grass clippings to a sward is an example of a thin mulch: the clippings will only, typically, cover a small amount of the surface as the aim would not be to effectively smother the surface like a traditional mulch, but to recycle and return nutrients to the sward.