Awgchew et al_2024 Characteristics of Soils Types along the Toposequence in Central Highlands of Ethiopia

Abstract

It is imperative to understand and predict the nature and distribution of soils along a given physiographic condition. However, the hitherto practices of collecting basic soil information at a site-specific level seem inadequate to assure sustainable agricultural production via proper utilization and effective management of soil resources. Therefore, this research was conducted to characterize, classify, and map the soils of the Qenberenaweti sub-watershed along a toposequence. A total of 91 auger inspections were made up to a 1.2 m depth to define soil mapping units with their boundaries using key topographic and morphological (slope gradient, soil depth, and texture of surface soils) features. Then, six pedons along the toposequence were opened at typical slope positions. The depth of the pedons varied between 135 and 200⁺ cm, whereas the thickness of A-horizons showed an increasing trend down the slope with an exception at the back-slope position. The textural class of all soils at the surface and subsurface horizons was clayey with different distributions of the three soil separates. The pH values of surface and sub-surface soils ranged from 5.59 to 6.23 and from 5.31 to 7.65, respectively. The OC contents throughout the entire horizons were varied from 0.22 to 2.03%. The highest CEC values were found at the middle positions while accordingly followed by pedons at the upper and bottom parts. The exchangeable Ca was the dominant cation of most pedons followed by Mg, K, and Na. Six soil types were identified as per the WRB system of classification. The results of this research revealed that the extent of variations in key topographic features brought the formation and development of the soil types along the toposequence. Therefore, such inclusive evidences help to ensure sustainable agricultural production through efficient planning, management, and utilization of the soil resource at the local topographic level.