03:29 Aug 4, 2011 

I'm assuming that '"suelo" is equivalent to 'soil' in English. See definition below. My understanding of the phrase here is that the nature of the soil lends itself to retention to create the desired topography.
Definition of soil:
Noun: The upper layer of earth in which plants grow, a black or dark brown material typically consisting of a mixture of organic remains, clay, and rock particles.