Carbon, nitrogen, and physical fractions of organic matter in recovered pastures of the Maranhense Amazon

In Maranhão State, Brazil, soils are naturally acidic, nutrient-deficient, and prone to cohesion erosion. Removing the natural cover establish pastures causes physical, chemical, biological changes in soil. Therefore, this study aimed evaluate contents stocks of carbon (C), nitrogen (N), particle-size fractions soil organic matter (SOM) with different years recovery, compare them a secondary forest Legal Amazon. Four treatments were evaluated: forest, perennial pasture, recovered for five eight years, both latter through corn + brachiaria intercropping. The total carbon, nitrogen, C, N from fractions, as well management indexes (CMI) 0.00–0.10, 0.10–0.20, 0.20–0.30, 0.30–0.40 m layers evaluated. pasture environment presented highest C contents; however, when observing granulometric CMI, these increases qualitative relation forest. Pasture recovery over contributed an improvement quality similar indicating that increase SOM quality, quantity, time related increased capacity accumulate