Quantifying carbon sequestration on saltland pastures in South West Australia

The large areas of saltland pastures in South West Australia offer opportunities for carbon (C) sequestration through re-vegetation. An investigation was carried out to quantify the amount of C sequestered in above- and below-ground biomass for wavy leaf saltbush (Atriplex undulata) at a saline site east of Wickepin with average EM38 readings of ~400 mS/m (in the vertical mode). The preliminary results showed that the above ground and below ground biomass was higher under ungrazed than grazed management systems. The amount of above-ground biomass was 10.8 t/ha (4.01 t carbon /ha) for ungrazed saltbush plants and 3.6 t/ha (1.34 t C/ha) for grazed plants. Similarly, root biomass in the ungrazed system had higher biomass [2.7 t/ha (1.02 t C kg/ha)] compared with the grazed field [1.03 t/ha or 0.38 t C/ha]. Saltbush clearly has the potential to sequester a substantial amount of carbon and further research is underway to determine how amounts of carbon sequestered vary with species, soil type, site salinity and hydrology.