Carbon dynamics in Vertisols as revealed by high-resolution sampling.

Abstract

Two Vertisol soil profiles under xeric soil moisture regimes, located at Qedma and Akko, Israel, were investigated and compared to a profile under ustic moisture regime, located in Hyderabad, India. Samples were taken in complete successive 2 cm thin layers down to about 180 cm depth or more. Organic and inorganic carbon were analyzed with regard to (super 13) C and (super 14) C concentrations. While all soils have radiocarbon ages of several thousand years BP, the depth distributions reveal substantial differences between the soil carbon dynamics. (super 14) C and, less pronounced, delta (super 13) C clearly reflect the pedoturbation process. Further, its strength is found to be related to mainly soil moisture regime, then clay content and land use. In one soil, a change of growing from C (sub 4) to C (sub 3) crops in the past can be concluded from the delta (super 13) C depth distribution.