Resumen

ĆIRIć, Vladimir et al. Effects of land use conversion on soil aggregate stability and organic carbon in different soils. Agrociencia [online]. 2013, vol.47, n.6, pp.539-552. ISSN 2521-9766.

Aggregate stability is an important factor of the soil functioning. Greater aggregate stability leads to greater soil organic carbon (SOC) preservation, while SOC acts as a key cementing agent in aggregation processes. The objective of this study was to investigate the effects of native vegetation conversion in soil aggregate stability and SOC concentration. The investigation was conducted in the Vojvodina Province, Serbia, in July 2009. Undisturbed soil samples were taken from Haplic Chernozem, Haplic Fluvisol and Gleyic Vertisol, at a depth ranging from 0 to 20 cm. A completely randomized experimental design was used with three replicates. Each soil type was considered under treatments 1) cropland >100 years, 2) native meadow and 3) native deciduous forest. The means were compared by the Tukey test (p≤0.05). The sampling distance between different land use areas was less than 200 m. Wet sieving was performed in order to obtain four size classes of stable aggregates (8000-2000, 2000-250, 250-53 and <53 ,µm). The soil organic carbon concentration in aggregate classes was determined by the dichromate wet oxidation method. The conversion of native vegetation to cropland caused the MWD reduction of 78 % in Haplic Chernozem, 55 % in Haplic Fluvisol and 50 % in Gleyic Vertisol, and the largest decrease was recorded in the content of aggregates 2000-8000 µm. The reduction of the SOC concentration in sand-free aggregates occurred mainly in the aggregates 532000 µm amounting to 48 % in Gleyic Vertisol and 52 % in Haplic Chernozem, whereas in Haplic Fluvisol was 52 % in the aggregates 8000-2000. The silt and clay fraction (<53 µm) showed the highest level of SOC preservation. Due to the high concentration of SOC and clay, Gleyic Vertisol showed lower susceptibility to aggregate stability deterioration and greater ability for SOC preservation than Haplic Chernozem and Haplic Fluvisol. This study also indicated the necessity for sand-free correction in coarse-textured soils.

Palabras llave : aggregate stability; soil organic carbon; land use change; soil type; soil structure.

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