SOIL PROPERTIES, CHARACTERIZATION AND CLASSFICATION OF SOILS ALONG THE BONEYA KETO TOPOSESEQUENCE AND LAND USE TYPES OF SILTE ZONE, SOUTHERN ETHIOPIA

Abstract

Characterizing and classifying the behavior of soil based on differences in topography and land use systems practiced is useful for sound soil management. To this effect, the influence of topographic positions (lower, middle, and upper) and land uses (cultivated land and grassland) on soil physicochemical characteristics were assessed and thereby classify the major soil types of the study area. Accordingly, a total of three pedons, one at each topographic position, were freshly opened and described for their morphological properties in the field. The soil samples from each of the identified horizons and surface composites (0-20cm) were collected from each land use at each topographic position and physicochemical properties of the soils were characterized in the laboratory following standard procedures. The result revealed that clay, silt, sand, EC, exchangeable potassium, CEC, and Fe were significantly (P ≤ 0.05) affected by topographic positions. Accordingly, the significantly highest concentration of clay and silt fraction, soil EC and exchangeable potassium were observed at lower topographic positions whereas, significantly higher sand content, CEC, Fe and Mn were recorded at upper topographic positions. Similarly, EC, Mg, K, Na, CEC, Fe, Mn and Zn were significantly (P ≤ 0.05) affected by land uses in which significantly highest of these parameters recorded under grassland. The observed relationship between topographic features, soil characteristics, and land use types will help to advance the understanding of soil-land use-landscape relation in the study area, and showed a less costly way of acquiring soil information. The results of the in-situ morphological description of the soil pedons followed by the laboratory analysis of the sampled horizons, soils were classified as Phaezomes Cambisols and Luvisols at upper, middle and lower topographic positions, respectively. Generally, surrounding landform and land use influenced soil properties, suggesting the need for different management practices for varying slope gradients and land uses for sustainable agricultural production.