The soils in Skapiškis area and their features

Vytas Mašauskas

Based on the data of soil investigations and literary sources, the paper deals with the processes of soil formation in Skapiškis area due to ice-sheet impact that resulted soils different in their origin and grain size; the geographic distribution of soils in the area of the former Skapiškis rural district (valsčius) is presented, their variations during nearly 25 years in agrochemical features, such as acidity, phosphorus and potassium content, are discussed, and the assessment of soil productivity is given.

The soils in Lithuania, including Skapiškis area, had been forming on the Quaternary deposits differing in thickness and covering the entire area of Lithuania. There were at least three obvious glacial periods and two interglacials.

The area of Skapiškis district belongs to the West Aukštaitija plateau region in Lithuania with varying and complicated relief being characteristic. At its western margin north-eastwards across Skapiškis, a wavy morainic plain stretches and a ravine-rich surface alternates with extending plains. Eastwards, the hills grow in number. At the western margin via Skapiškis north-eastwards, wavy morainic plains stretch with boulder stripes and old ice-margin valleys.

Different soils had been formed depending on relief, climate, vegetation, fauna and human activities with different soil forming processes taking place, such as decalcification, decarbonisation, formation of brown earths, gley and/or podzol soils, peat and bogging.

In the district of Skapiškis notable for wavy land surface alternating with plains, according to the former classification (TDV-96), the gleyic sod-podzolic (JvP1) soils prevail followed by sod gleyic (VG1) soils; while according to the LTDK-99 classification accepted in 1999 and agreed with FAO, the gleyic luvisols (IDg) and gleyic cambisols (RDg ) dominate. Higher sites with smaller areas contain, according to TDV-96 classification, automorphous (with normal moisture level, or episodically moist) slightly podzolised sod-podzolic (J1v) soils, or luvisols (ID) according to the LTDK-99 classification occur. The lower sites contain sod gleyic (VG2) soils, as well as episodic humic gleyic (VG2p) and marsh (P) soils according to the TDV-classification, corresponding to gleysols (DL) and histosols (PDž) of the LTDK-99 classification.

The soils in the area of Skapiškis had been formed in the glacier-brought till deposits of different grain size with sandy loam and loam prevailing. Their typical feature is that they contain boulders and possess high calcariousness. Other groups of rocks, such as glacio-fluvial deposits had been settled by ice-sheet melt-water as sand or rarer as gravel, as well as glacio-lacustrine deposits settled under calm water conditions as different loam, clay and sand, formed the soils, which occupy small plots in the area of Skapiškis. Alluvial deposits had been settling, and this process is going on in the floodplains of rivers and lakes or even small river valleys. Their occurrence in the Skapiškis regions is observed in smaller plots. They are mainly deposits of light clay loam and sandy loam. Organic deposits had been formed during the post-glacial period from abundance of plants and moisture in the relief sinks. According to the vegetation and the degree of mineralisation they are attributed to the type of low moors.

The characteristics of various soils–grain size composition, moisture regime, thickness of humic layer, acidity, content of nutrients – have been assessed applying approved investigation methods and expressed as one general indicator of soil features, i. e., bonitation or fertility point in a 100-point system, which enable to make comparison of different soils. According to the Cadastre 2011 data of land-use plots, the fertility of such plots in Skapiškis neighbourhood is valued as 42.40, while in Kupiškis District this indicator for all agricultural land plots is 41.80 and nearly coincides with the average value for all Lithuania (41.85).