Variability of Soil Properties in Eroded Agricultural Landscape

Erosion strongly influences the soil properties and affects the intra-field variation of nutrients not only in steep young morainic landscapes but also on gentle slopes of old-glacial landscapes. The aim of the study was the evaluation of changes in the plant-available nutrient contents in the complex old-glacial eroded landscape of the Bielska Plain in the north-eastern part of Poland. The soil samples were collected from the soil profiles located along the transect beginning on the flat summit of the kame hummock extending through south-facing convex slope, the toeslope and footslope and further through the north-facing uniform slope. The content of plant-available forms of phosphorus (P_dl) and potassium (K_dl) and mineral forms of nitrogen (NH₄-N and NO₃-N) were determined in every soil profile. The soils located in various landscape positions were characterized with different fertility. In the soil located on the toeslope the content of NO₃-N, P_dl and K_dl was high, while the soil located on the summit was rich in NH₄-N and poor in the plant-available forms of K and P. The erosional distribution of plant-available N, P and K enhances the variation of nutrient content within one field and contributes to high variability of crops.