I did a little more checking and this is what I found for Pedro Martinez of Alamosa, Colorado

From WWI Draft Reg Card
Pedro Martinez, born: April 14, 1897, born in Alamosa, Colorado
Father’s birthplace: San Luis, Costilla County, Colorado

In 1930, he is listed in the US Federal Census as living in Alamosa, Colorado with the following household:
Pedro Martinez, age 32
Carmel Martinez, age 31
Saraida Martinez, age 10
Ben Martinez, age 6
Frank Martinez, age 1

In 1920, Pedro and Carmel is found in the US Federal Census as living in Alamosa, Colorado, next door to an Antonio D. Martinez, age 51, wife Petra, 49 and John, age 21
It is very likely that this is his father and mother.

In 1910, a Pedro Martinez is listed as 13 years old, son of Antonio and Petra Martinez, living in San Pedro, Costilla County, Colorado as a part of the following household:
Antonio Martinez, born: circa 1867
Petra Martinez, born: circa 1873
Dolceania Martinez, born: circa 1894
Pedro, born circa: 1897
Donscio Martinez, born circa 1899
Leon Martinez – Antonio’s brother
Bartolo Lovato, brother in law, age 60
Delfino Martinez, brother, age 7