Mulch: the great

Mulch: the great cover-up - varieties and application techniques
WHEN A LEAF FALLS IN THE woods, it is not likely that anyone would pick it up. Leaves, plant litter and other organic debris cover the forest floor, grass layers build up over the prairie and rocks and gravel top off the sandy soil in desert areas. No matter what the climate or topography, the soil in nature is covered with some kind of mulch. It pays for us to apply this lesson in our home gardens as well, to reap the benefits that nature has enjoyed from the beginning.
FOUR REASONS TO MULCH
Smother out weeds. A mulch on top of your soil reduces weeds in two ways. First, it blocks the weed seeds that blow into the area from above by providing a less hospitable germination bed than bare soil. Second, it blocks many weed seeds already in your soil that may try to sprout up from below. The deeper the mulch, the more weeds you will block.

For more effective weed blocking, lay down a three-page layer of newspaper before applying your mulching material. The newspaper will provide an additional weed barrier and will decay into the soil over time.
Conserve moisture. Water evaporates more quickly from soil that is left naked. A mulch not only shades the soil from the hot sun, but organic mulches soften the earth and improve aeration as they slowly decompose. This softening encourages plant roots to reach down deeper, where they are more likely to find moisture on their own.