Features of profile distribution and nutrient stocks in drained peat soils

Abstract

The profile distribution and stocks of organic carbon, total nitrogen and phosphorus, as well as C/N ratio, pHKCl and bulk density were studied on drained peat array in soils of various structure and thickness (southern Karelia, Fennoscandia) to assess the impact of long-term agricultural use of land with meadow vegetation. The highest degree of peat decomposition was characteristic of the shallow Histic Gleysols. In almost all the studied soils the content of nitrogen and phosphorus in the upper part of the soil profiles was higher than in the lower parts, while carbon content and the C/N ratio were lower. In Drainic Eutric Histosols and Murshic Eutric Histosols the carbon stocks in the 1-meter layer are similar and amount to about 700 t/ha. The total nitrogen stock depends on the degree of organic matter mineralization and decreases from 24 t/ha in Drainic Eutric Histosols to 13 t/ha in Histic Gleysols. The total phosphorus stocks are significantly higher in Histic Gleysols (5.5 t/ha) and Murshic Eutric Histosols (7.4 t/ha) compared to slightly disturbed Drainic Eutric Histosols (3.2 t/ha). All the studied properties have almost similar values in layers deeper than 40 cm in the Drainic Eutric Histosols and Murshic Eutric Histosols, which is due to higher water content and more stable hydrological regime in the deep layers of the peatland.

Keywords

• histosols
• histic gleysols
• land use change
• stocks
• organic carbon
• total nitrogen
• total phosphorus
• meadow vegetation