Spain and England had different strategies when it came to race relations when they started to control big territories in the western hemisphere.
Spain was mainly focused on assimilation, they wanted the Europeans to mix with the native tribes and the Africans, so in this way to create a greater unity between the people and to create a mixed race where most of the people were sharing traits from all three races and thus avoid problems in that department. Also, Spain was not not much up for the slavery, but instead considered the imported, bought people as workers, and they were free in general.
England on the other hand, was much more rigorous, the slavery was essential part of its rule and it lasted for pretty long time, and the native populations were oppressed, killed, tortured...