Ninety percent of their roots are in the top few inches of soil, so the trees rely on the litter to keep the soil from drying out. (sciencedaily.com)
To people who believe there may once have been life on Mars, this is why the Viking landers in the 1970s found no evidence of it: They scooped samples only from the top few inches of soil. (discovermagazine.com)
Scatter the grounds over the soil in your garden and till them into the top few inches. (wellnessmama.com)