CARBON STOCK AND SOIL AGGREGATION UNDER DIFFERENT USE SYSTEMS IN THE CERRADO

Abstract

The objective of the work was to evaluate the carbon stock and soil aggregation
in different management systems in the municipality of Aquidauana-MS. Soil
samples were collected in the 0.0–0.1 m layer, in six areas: exposed soil (ES),
conventional brewing system (CB), no-till system (NT), sugar cane (SC), permanent
pasture (PP), and native forest (NF). From the samples, the: total organic carbon
(TOC) was determined, density of the soil (Sd), being calculated the carbon stock
(EstC), and the variation in the carbon stock (ΔEstC), in addition to the aggregate
stability analysis, obtaining: weighted average diameter (WAD), geometric mean
diameter (GMD), and percentage of aggregates retained in the sieves. The results
were analyzed in completely randomized design (CRD), in addition to canonical
analysis. The highest Sd values were observed in the ES 1.53 Mg m-3, CB 1.46 Mg
m-3, NT 1.47 Mg m-3, and SC 1.46 Mg m-3 systems. The TOC levels in the PP and
NT areas were higher than the NF. EstC has the same TOC pattern. As the areas of
PP and NT presented values of WAD, GMD similar to NF. As PP, NT and NF areas
had more than 60% of their aggregates larger than 2mm. A canonical analysis
indicated the formation of 3 groups, one with ES and CB, another with only
SC, and the third composed of NT, PP, and NF. The ES committed the CB to the
carbon stock and soil aggregation in layer 0–10, whereas PP and NT increased
the carbon stock in that same layer.