Effect of land use change on soil organic carbon

The direction of changes and conversion of soil organic carbon (SOC) is in most current ecosystems influenced by human activity. Soil Science and Conservation Research Institute is responsible for monitoring the agricultural soils in a five-year cycle. One part of the soil monitoring involves the determination of the soil organic carbon (SOC) storage. Further, we followed the conversion of arable land on grassland during more than 20 years of monitoring period at some locations where changes in land use occurred. Ten places on basic network and 2 places on key monitoring localities in which arable land have been converted into grassland were identified. About 50 percent of studied soils converted into permanent grassland were Cambisols. The other converted soil types were Luvic Stagnosol, Stagnic Regosol, Mollic Fluvisol, and Stagnic Luvisol. The results showed that after the third monitoring cycle (2002), increase of SOC was observed in all the localities, with the change in land use. Statistical parameter (t-test) confirmed significant differences between the set of average SOC values before and after the land use conversion. The chemical structure of humic acids (HA) isolated from arable soil and permanent grassland indicated increasing of aliphatic carbon content in grassland HA. More aromatic and stabile were HA isolated from arable soils.