I think the stratosphere but I am not positive...i could be wrong
The geography of the United States impacts the possible regions people settle in.
Areas that tend to be flat (or small amounts of small hills) tend to be the most population areas because it is easier to build houses, apartments, etc etc. However there is very few places people have settled where National Parks and Mountains are located because it is unstable and extremely difficult to make a house in that region.
Lapita people and Polynesians were considered nomads before,
meaning no permanent settlement. These
people searched for places suitable for the type of living that they have. For example, that who settled in farmlands
and have animals to raise finds places suitable for farming. Others go near the
sea or rivers in order to go fishing.
Answer:
She's trying to enrich the soil with nutrients.
Hope this helps & good luck!
Feel free to message me if you need more help! :)