Asian Journal of Soil Science and Plant Nutrition

A reconnaissance soil survey was conducted to characterize soil properties and classified the soil according based on toposequence from 2012 to 2013 at Gobeya sub-watershed of Tehuledere District, South Wello Zone of Amhara Region of Ethiopia. The topographic map (1:50,000) was used to define the preliminary boundary of the Sub-watershed and soil mapping unit (SMU), and as well as to select temporary profile or sampling sites before the actual field survey. The soil survey and classification was done according to FAO guideline. Free soil survey (traverse survey) method was applied to select profile excavation points as a major survey method along landform to detect variability of soils in the Sub-watershed. The studied area were divide into SMU-1 (152.5 ha), SMU-2 (89.4 ha), SMU-3 (45ha) and SMU-4 (218.1ha). The observation was made along the toposequence and 99 auger samples were taken from different sites up to 30 cm depth and analyzed in the field in order to observe the extent of variation of soil attributes. Four soil profile pits (2.0 m width, 2.0 m length and 2.0 m depth) were excavated at summit, shoulder, footslope, and toeslope positions and to represent the SMU. A total of 12 disturbed soil samples from each genetic horizon and 7 undisturbed soil samples from the upper two horizons were collected from all profiles. Based on the results, the soils were classified as Vertic Cambisols (Humic, Hypereutric, Endoskeletic) about 152.5 ha (30.2%), Haplic Regosols (Hypereutric) about 89.4ha (17.7%), Mollic Leptosols (Humic, Epieutric) about 45 ha (8.9%) and Haplic Cambisols (Humic, Hypereutric) about 218 ha (43.2%). The major chemical fertility problems in all soils of the study area were low level of available P, total N and exc hangeable K.