Land use effects on soil organic carbon sequestration in calcareous leptosols in former pastureland – a case study from the Tatra Mountains (Poland)

Abstract

Abstract. The purpose of the paper is to show SOC sequestration rates in calcareous shallow soils in reforested areas in Tatra Mts. with a particular focus on the different forms of organic matter (OM) storage. Three plant communities creating a mosaic on the slopes of the valley were taken into account. After 50 years since the conversion of pastureland to grassland, dwarf pine shrub, and larch forest on soils, the development of genetic soil horizons as well as SOC sequestration in soil occur despite the steepness of slopes. SOC stock is the highest in soils under larch forest (63.5 mg ha−1, SD 16.3), while in soil under grassland and under dwarf pine shrub, this value is smaller (47.5 mg ha−1, SD 13.3 and 42.9 mg ha−1, SD 22.0 respectively). The highest amount of mineral-associated OM inside stable microaggregates (MOM FF3) is found in grassland soil (21.9–27.1% of SOC), less under dwarf pine shrub (16.3–19.3% of SOC) and larch forest (15.3–17.7% of SOC). The pool of mineral-associated OM inside transitional macroaggregates (MOM FF2) is found in soil under dwarf pine shrub (39.2–59.2% of SOC), with less under larch forest (43.8–44.7% of SOC) and the least in grassland soil (37.9–41.6% of SOC). The highest amount of the free light particulate fraction (POM LF1) is found in soil under dwarf pine shrub (6.6–10.3% of SOC), with less under larch forest (2.6–6.2% of SOC) and the least in grassland soil (1.7–4.8% of SOC).