Characterization and classification of soils along the toposequence at the Wadla Delanta Massif, North Central Highlands of Ethiopia

Abstract

The knowledge of soil properties and availability of reliable soil data play vital role in understanding the soil environment and its services. This study was conducted with the objective of characterizing and classifying soils of Wadla Delanta Massif, North Central Highlands of Ethiopia. Twelve representative soil pedons (profile pits) were opened on various landscape positions, described in the field and horizon-wise samples collected for morphological and physicochemical analysis. Variations in color (moist and dry) within a pedon and among pedons along the toposequence were observed with grayish, dark brownish or black colors dominating the surface layers, while stronger and brighter colors with shades of reddish brown and light brownish gray dominated the surface layers. The soils are heavy clays (35 to 80%), of low bulk density (1.02 to 1.35 g cm-3), acceptable ranges of particle density for mineral soils (2.41-2.82 g cm-3) relatively high total porosity (46.51-60.55%), and high available water holding capacity (129.9-287.9 mm m-1).The soils were slightly acidic to moderately alkaline (6.25 to 8.29) in their reaction, salt free (EC < 0.5 dS m-1), very low to medium in organic matter (0.12 to 4.82%) and total N (0.02 to 0.28%) contents, and available P (0.52 to 18.44 mg kg-1), high to very high in CEC (31.98 to 65.48 cmolc kg-1), exchangeable bases and base saturations (60.22 to 98.97%), with medium status of micronutrients occurring in order of Fe (0.82-10.40 mgkg-1) >Mn (2.01-9.22 mgkg-1) > Cu (0.80-6.03 mgkg1) > Zn (0.80-5.80 mgkg-1), all of which were above the critical limit. Based on morphological, physical and chemical analysis, and the FAO-WRB Soil Classification System, the soils are classified as MaziPellic Vertisols, Mazi-Calcic Vertisols, Haplic Cambisols and Mollic Leptosols. The soil potentials are hampered by their stickiness when wet and hard when dry, waterlogging and soil erosion due to inappropriate tilling and timing of cultivation. Therefore, integrated soil management is essential in the area.