Morphology and chemical properties of plough horizons of soils in various slope positions

Abstract

Studies on morphological features and chemical composition of Ap horizons of soils located on gentle Narew valley-sides were carried out. The Luvisols with a texture of loamy sands and sandy loams are developed on the slope shoulder while the Mollic Gleysols of a similar texture with deposits to 110 cm thick are located on the footslope. The soil particle size distribution and total nitrogen (TN), total porosity (TP) and KH2SO4 H2O2 _ content in both slope positions are similar. The mean TN, TP and KH SO H O 2 4 2 2 _ content on the slope shoulder is 0.94, 0.36 and 1.26 g kg-1, respectively, while soils on the footslope are characterized with a mean content of total nitrogen, phosphorus and potassium of 1.15, 0.35, and 1.17 g kg-1, respectively. Plough horizons of soils located on the footslope are more acidic with higher Corg content. The mean exchangeable acidity in deluvial soils (4.20 cmol(+) kg-1) is higher than in soils located in upper slope positions (2.92 cmol(+) kg-1). Similar texture of soils in both slope positions as well as thick deluvial deposits on the footslope is evidence of tillage erosion as the main factor of soil downslope translocation on these gentle slopes.