Drylands cover about 40% of the planet, in which 44% are occupied with cultivated systems. Covering 45% of Brazilian Semiarid the grasslands are main land use this region. In order to increase biomass production and provide food for goats, sheep and bovines are implanted different agrosystems with differences species Cenchurs ciliairis L. (CC), Opuntia ficus indica Mill. (OF), Gliricidia sepium Jacq. (Walp.) (GS), Leucaena leucocephala Lam. De Wit. (LL). However, with removal of native vegetation (NV) there is a change in supply plant material and hence in soil organic matter (SOM), which is formed by substances in different stages of decomposition. Among the chemical components contained in SOM is carbon (C), the main structuring element of nature. In soils, the C can be in the form particulate organic carbon (POC), coming from the biotic residues being quite susceptible to change of land use, and mineral-associated carbon fraction formed by organomineral complexes that are not available to decomposition . POC is associated with the active compartment and can be lost more eas ly, depending on land use. In sense, to evaluate how the introduction of new species for animal feeding can modify the POC, soil samples were collected at following depths: 0-5, 5-10, 10-15, 15-20, 20-30, 30- 40 cm, with four replicates for uses with different ages: NV (always preserved), CC (30 yr), OF (21 yr), GS (17 yr) and LL (24 yr). The air dried soil was separated in a 53 ?m sieve, where the particles larger than >53 ?m corresponded to POC
