The answer to your first question is the land becomes a lot dryer, so plants die. The answer to your second question is deposition.
“Grass is a monocotyledon plant, herbaceous plants with narrow leaves growing from the base. A common kind of grass is used to cover the ground in a lawn and other places. Grass normally gets water from the roots, which are located in the ground.” This is NOT my information I found it on Wikipedia hope this helps
