The No-Till Approach
Lasagna Gardening is a method in which the sod or topsoil is not tilled or ploughed under to prepare for planting. Instead, the ground is covered with material, sort of like a compost pile, to stop the growth of the existing vegetation. Then the of the Lasagna pile is plantable soil. As the garden or lawn ages, the layers of material composts and decomposes, and the soil becomes healthier and more productive.
I have constructed vegetable gardens in this fashion. The picture on the front page for instance. As well, I have rebuilt a back lawn that was being overrun by a noxious weed using this method.