By holding onto water, mulch prevents it from puddling or causing erosion while keeping it in the soil.
(mulch; prevents; it; from puddling or causing erosion) (it; from puddling; ) (it; causing; erosion; T:while keeping it in the soil)
mulch it it
prevents from puddling causing
it from puddling or causing erosion
erosion T:while keeping it in the soil