Read the following passage and answer the questions that follow:-
The first truck to arrive is no. 4272, a seventy-three-foot-long tractor-trailer, driven by Herman Snook, 67 years old, wiry, chewing a toothpick. He is quick to point out that he, too, thinks the landfill looks nothing like a landfill, and he believes it doesn’t smell like one, either. He allows that he may have just gotten used to the odor. (He has.) When fellow truckers arrive, pulling up next to Herman, the ground—so deep with trash—is so soft it bounces.
At six o’clock, the truckers are allowed to start dumping, and so Herman pushes a red button inside a panel on his cab. The back end of the trailer rises obediently and 79,650 pounds of debris comes thundering out, most of it wood and plaster and nails and shreds of wallpaper. Beside him, a truck is dumping decidedly more organic garbage, pungent indeed, and way down the row, off¬ to the side, a guy is pouring a truckful of sludge, sterilized human waste, black as ink.
The Puente Hills Landfill, about sixteen miles east of downtown Los Angeles, serves 5 million people in seventy-eight California cities, one of six landfills operated by the Sanitation Districts of L.A. County. Every day 13,200 new tons of trash are dumped here. That’s enough to fill a one-acre hole twenty feet deep.
In five years, on November 1, 2013, the landfill will be out of room, and all that trash will have to go somewhere else.
What does the author mean by, “ the ground—so deep with trash—is so soft it bounces.”?