ITG FAQ #16 Answer-What is meant by the term "directly derived from the land"?
This term can be construed literally to mean that income must be sourced from the land itself. Such exempt income includes: rentals (including crop rentals); royalties; proceeds from the sale of the natural resources of the land; income from the sale of crops grown upon the land and from the use of the land for grazing purposes; and income from the sale or exchange of cattle or other livestock raised on the land. Proceeds from the sale of restricted allotted land while the fee title is still held by the Government in trust for the Indian are also exempt from tax.
NOTE: This term does not include income from a smokeshop, motel, gift shop, or gaming.