Unfortunately wrong Johann Goosen. The one who had a granddaughter Martha Berg is this one: https://www.familysearch.org/tree/person/details/9JMG-GRV
Living 1910 in Washita County, OK, with wife whom he had married in 1880; daughter Sarah (mother of Martha Berg) in adjacent family. Familysearch has a marriage record for 1880 in Korn/Corn, Washita County; however, that county was not formed until 1892, and it is apparently in that year that the Mennonite community of Korn (settled by Germans from Russia) was established. Daughter Sarah, age 26 in 1910, in that census stated she had been born in "Russ German".