Historical soil maps with a reference to redoximorphic features as basis for ecohydrological modelling.

<p>Historical soil maps with a reference to profile redoximorphic features have obvious utility for ecohydrological modelling. That is particularly pertinent in areas with shallow water tables where catchments have both dry and moist parts, latter due to moisture source from either upper or low boundary. However, there is no convenient method for converting maps to hydrological model state variables. Here we propose that the steady state continuity equation in kinematic wave form can be parameterized using expert knowledge of the typical water table depth (WTD) for soils with different hydromorphy degrees based on redoximorphic features. To test the approach, six hillslope-based computational units (catenas) were obtained, for use in simulations, by automated of the Samovetc and Izberdey catchments in the Tambov region (Russia) using lumpR software. Five of the six catenas began at poorly drained flat upslope positions with soils with various degrees of saturation by shallow groundwater and one began at a well-drained upslope position. We guided parameterization of the kinematic wave model by critical range of the WTD known to correspond to each soil group on historical soil map of hydromorphy degree. Application of expert knowledge in this manner alone yielded a broad range of possible WTD values (e.g. 1.5-5 m for a semi-hydromorphic soil) for each soil entity, but linking a catena by the fundamental physical constraint of flow continuity enabled narrowing of the range to 0.2-1 m thereby reducing it by ca. 80%. We further tested the shallow water table approximation in the WASA-SED ecohydrological model based on catenary approach to simulate soil moisture profiles referring explicitly to soil groups of different hydromorphy degree and distinguish stagnic and gleyic regimes of waterlogging. The results show that the approach could substantially improve crop and water management precision.</p>

Classification of mountain soils in a subalpine zone – a case study from the Bieszczady Mountains (SE Poland)

The aim of the study was to test the suitability of the 6th edition of Polish Soil Classification (SGP6) in reflecting the typical features of subalpine Bieszczady Mts. soils in comparison with the 5th edition of Polish Soil Classification (SGP5) and the newest version of World Reference Base for Soil Resources (WRB). Five soil profiles located in differentiated in terms of the parent material, topography and vegetation conditions of the natural environment were investigated. On the basis of described morphology and determined properties soils were classified according to different soil classifications. All soils under study were featured by presence of thick A horizons and high content of soil organic carbon accumulated even very deep in the profiles. Some of the mineral topsoil layers were classified as umbric/umbrik horizons. Moreover cambic/kambik horizons were present and in some cases also weak redoximorphic features occurred. The SGP6 enabled to distinguish soils with a thick, organic carbon-rich A horizons as umbrisols, a newly created subtype of grey soils. Furthermore, the soil taxonomic position according to SGP6 was more detailed in relation to the soil trophic status (in case of brown soils) and occurrence of weak redoximorphic features. That was reflected in number of subtypes to which analyzed soils were classified – 4 in SGP6 vs 2 in SGP5.