You cannot promise to become a U.S Citizen. You have to be born in the U.S to be an actual citizen. If you were born in another country, you are not a citizen. Besides that, if you were living in America for at least 13 years, you must pass a test in order to become one.
First you have to write a letter to the government, explain why you need land. Last with a map you show where and you have to promise to raise cattle. And one more, you have to promise to be Mexican citizen.