in 0-15 cm depth over 13-year period, respectively (see Table 8). However, another study in southwestern Nigeria also showed that alley cropping systems (with and Leucaena Gliricidia) did not prevent the decrease in SOC pool despite their effectiveness in soil erosion control (Lal, 1989b; c). 73. In view of the potential synergies between existing multilateral environmental agreements in the implementation of land use change and forestry activities (e.g., the overlap among UNCCD, UNFCCC, and UNCBD) (Cowie et al., 2007), there is a need to identify policy options for facilitating beneficial forestry/agroforestry systems and other land use changes. For this, the data on the technical potential of C sequestration is needed for such land use systems. Watson et al. (2000) estimated that 400 Mha of area under agroforestry systems could sequester C at the rate of 0.72 t C/ha/yr. Nair et al. (2008) estimated that the global area under agroforestry systems of 1,023 Mha can be increased to sequester C. Dixon (1995) estimated that 585-1215 Mha of area under agroforestry systems (in Africa, Asia, Americas) has a technical potential for C sequestration of 1.1-2.2 Gt C/yr. Dixon also estimated that an additional 630 Mha of croplands and grasslands that are currently fallow or marginal lands primarily in the tropics could be converted into agroforestry. E. Biochar 74. Biochar refers to charcoal produced from biomass. Appropriately used, biochar can be applied as soil amendment for improving soil physical and biological properties (Sombroek et al., 2003; Rumpel et al., 2005; Lehman and Joseph, 2009). With high application rates, it can also lead to SCS especially in situations where biochar may be available. Biochar can by produced from surplus biomass such as those from sawmill, dairy farms, food processing units, rice husking mill, timber yard, etc. Biochar may also be produced as a co-product of a biofuel
in 0-15 cm depth over 13-year period, respectively (see Table 8). However, another study in southwestern Nigeria also showed that alley cropping systems (with Leucaena and Gliricidia) did not prevent the decrease in SOC pool despite their effectiveness in soil erosion control (Lal, 1989b; c). 73. In view of the potential synergies between existing multilateral environmental agreements in the implementation of land use change and forestry activities (e.g., the overlap among UNCCD, UNFCCC, and UNCBD) (Cowie et al., 2007), there is a need to identify policy options for facilitating beneficial forestry/agroforestry systems and other land use changes. For this, the data on the technical potential of C sequestration is needed for such land use systems. Watson et al. (2000) estimated that 400 Mha of area under agroforestry systems could sequester C at the rate of 0.72 t C/ha/yr. Nair et al. (2008) estimated that the global area under agroforestry systems of 1,023 Mha can be increased to sequester C. Dixon (1995) estimated that 585-1215 Mha of area under agroforestry systems (in Africa, Asia, Americas) has a technical potential for C sequestration of 1.1-2.2 Gt C/yr. Dixon also estimated that an additional 630 Mha of croplands and grasslands that are currently fallow or marginal lands primarily in the tropics could be converted into agroforestry. E. Biochar 74. Biochar refers to charcoal produced from biomass. Appropriately used, biochar can be applied as soil amendment for improving soil physical and biological properties (Sombroek et al., 2003; Rumpel et al., 2005; Lehman and Joseph, 2009). With high application rates, it can also lead to SCS especially in situations where biochar may be available. Biochar can by produced from surplus biomass such as those from sawmill, dairy farms, food processing units, rice husking mill, timber yard, etc. Biochar may also be produced as a co-product of a biofuel