CARBON STORAGE IN THE CALICHE OF ARID SOILS

Abstract

Using data from 91 Arizona soils, I calculated the accumulations of organic- and carbonate-carbon in different soil orders and ecosystem types. Regional accumulations were examined relative to precipitation, elevation, and parent material. The largest accumulations of pedogenic carbonates were found in Aridisols and in areas of desert scrub vegetation, where carbonate-carbon exceeded organic carbon by a factor of > 10. In soils under woodland vegetation, organic carbon accumulations predominated. According to the Arizona data, I estimate that more than 800 X 1015 grams of carbon are stored in the caliche layers of the world's Aridisols and arid Entisols.