Abstract

Soils of the lowlands in southwestern Ethiopia are under intensive cultivation, however, very little is known about them. The objective of this study is to provide basic information on how pedogenic properties along the landscape relate to their use, which could assist better management to establish sustainable crop production system. Four soil profiles from varying slope positions and land management were described in-situ, and sampled horizon-wise for physico-chemical analysis. Accordingly, soils at upper-slope position (Pedons 2 and 4) were characterized by shallow depth with the upper boundary of C-horizon 47/52 cm from the soil surface, whereas those at lower-slope position (Pedon-3) exhibited thick sola with a deep C-horizon (>200 cm). The C-horizon of all Pedons, except Pedon-3, had high coarse fragments, ranging from gravelly (48%) to extremely gravelly (69%). The soil consistence (wet) showed various grades of stickiness and plasticity along the profile depth. Soil organic carbon (OC), total N, exchangeable bases (Ca, Mg, K) and cation exchange capacity (CEC) generally decreased with profile depth, whereas available P content showed increasing trend with depth of Pedons and along the slope, ranging from 8.7 to 33.7 mg kg^-1. According to WRB legend, Pedon-1 and 2 with cambic horizons were classified as Haplic Cambisols and Fluvi-Mollic Cambisols, respectively, whereas Pedon-3 was classified as Leptic Regosols soil unit. Overall, this study revealed that the effects of land management on soil properties as a function of landscape is profound, suggesting the need for developing appropriate management options for sustainable use of the land. 

Key words: Landscape, Pedon, slope, soil characteristics, soil classification.