95. The total potential of degraded lands restoration and desertification control to sequester C is shown in Table 30. The total potential is 0.6-1.7 Gt C/yr, with a mean of about 1.2 Gt C/yr. The SLM options to achieve this potential include restoration of eroded lands, reclamation of salt-affected soils and production of biofuel feedstock through halophytes. Squires et al. (1995) estimated that management of drylands through desertification control has an overall C sequestration potential of 1.0 Gt C/yr. These high estimates are in contrast to overall low C storage potential of world soils estimated by Schlesinger (1990). Estimates presented in Table 30 are crude, tentative, and merely suggestive of the high potential that exists if judicious land use measures are adopted in the drylands. Uncertainties are high and may be 30 to 50%, as is evidenced by a wide range in the rate of C sequestration in soil and biomass. Further, estimates of potential for different strategies are not additive, and the data need to be used with due consideration of site-specific conditions. The potential of C sequestration in the ecosystem is computed for a 50-year period. Although C sequestration in an ecosystem can continue for up to 150 years (Akala and Lal, 2000), the rate and cumulative amount of sequestration are high only for up to 50 years. Upon conversion to restorative or improved systems, rate of C sequestration may peak within 10 to 15 years. Therefore, for practical purposes, 50 years is an adequate period to estimate the potential (Lal et al., 1998).
