Compare and contrast histosols and aridosols, the soils of bogs and peat marshes versus those of deserts and arid regions respectively.

In both the FAO soil classification and the USDA soil taxonomy, a histosol is a soil consisting primarily of organic materials. They are defined as having 40 centimetres (16 in) or more of organic soil material in the upper 80 centimetres (31 in). Organic soil material has an organic carbon content (by weight) of 12 to 18 percent, or more, depending on the clay content of the soil. while aridosols are a soil order in USA soil taxonomy.[1] Aridisols (from the Latin aridus, for “dry”, and solum) form in an arid or semi-arid climate. Aridisols dominate the deserts and xeric shrublands, which occupy about one third of the Earth's land surface. Aridisols have a very low concentration of organic matter, reflecting the paucity of vegetative production on these dry soils. Water deficiency is the major defining characteristic of aridisols.

Gay-lussac's law i think.