CARBON STOCK AND SOIL AGGREGATION UNDER FOREST FRAGMENTS IN THE ATLANTIC FOREST AND CERRADO BIOMES

Abstract

Carbon stock (EstC) and soil aggregation were studied in and around forest
fragments of the Atlantic Forest (AF) and Cerrado (CE) biomes. Soil samples
were collected from four forest fragments; two in AF and two in CE. In
the fragments, three internal points were sampled: edge (EF), half radius
(HR) and center (FC), besides a point around; no-tillage system (NTS) and
permanent pasture (PP) in AF and CE, respectively. Total organic carbon
(TOC) and soil density (Sd) were determined with EstC calculations and
aggregate stability. In AF, Sd reached 1.19 Mg m-3. Higher TOC and EstC
contents were verified in the FC, reducing the FC EstC for more peripheral
points. Less soil structural stability was found in the surrounding NTS areas.
The areas of PP around the CE fragments presented higher Sd. The TOC
contents and EstC values were heterogeneous between the internal points
of the CE fragments. In the CE fragments, the structural variables did not
differ from the surrounding PP areas. The TOC and EstC indicate the most
conserved FC point in the AF fragments. In CE, the PP areas presented the
same potential of carbon accumulation in subsurface layers in relation to
the fragments. Forest fragmentation, in both studied biomes, modified the
physical attributes of the soil, besides influencing the carbon storage patterns
inside the fragments.