Soil water retention properties of forest soils under different land use.

Soil water retention properties of Eutric Leptic Cambisols Ochric, Dystric Cambisols Ochric and Dystric Cambisols Humic (IUSS Working Group WRB. 2015) under different land use (herbaceous, deciduous and coniferous vegetation) were evaluated using procedures similar to those described in ISO 11274:1998. The analyses were performed on undisturbed and disturbed soil samples taken from eleven surface (0-5 cm) and ten subsurface (10-25 cm) soil layers from 11 soil profiles within the territory of the experimental stations of the Forest Research Institute in the Gabra, Govedartzi and Igralishte Villages. The soil water retention curves were fitted with the van Genuhten model. The values for soil water retention at suctions lower than pF 2.5 (field capacity) varied significantly among the studied sites – from 6.9 to 60.6%. The influence of the total soil organic carbon content (SOC) on water retention was quantified using regression equations. SOC varied from 0.32 to 6.79% depending on soil differences, vegetation type, altitude and degree of soil erosion. The increase of clay in the surface layer of strongly eroded soils (Eutric Leptic Cambisols Ochric) on the grassland sites at the Gabra station also increased the water retention capacity. The obtained data for water retention characteristics of the studied shallow soils can be applied for estimation of soil water and energy balances.