The study looked at how soil organic carbon changes at different depths in a semi-arid area. They found that carbon content and density decrease as you go deeper into the soil. Carbon density on the surface decreases with altitude, but deeper soil carbon doesn't change much with altitude. Overall, the area studied has a total organic carbon reserve of 2.04×105 tons, with the middle layer holding the most carbon. The study shows that soil organic carbon storage is related to the altitude of the area.