Keywords: Soil, Physical and Chemical Properties, Top sequence, Abamidian sub watershed
The research aimed to assess the variability in some selected physico-chemical properties of soil along a toposequence in Aba-midan sub water shed. Soil samples were collected by completely randomized factorial design from two different depths, 0-20 cm and 20-40 cm at each topographic unit. A total of 18 samples were collected, air-dried, crushed and sieved in a 2 mm sieve before laboratory analysis. Mean and coefficient of variation were statistically calculated. The composite sample of surface and sub surface results also showed a significant difference among the selected physicochemical properties of higher, middle and lower slope soils. Highest sand content (43%) was observed on the upper slope and the lowest (29.33%) was recorded in the middle slope. Whereas the average clay fraction of the upper, middle and lower slopes were 41.16, 55.66 and 49.33%, respectively. Likewise, Total nitroge (0.21%), Organic matter (4.07%), available Phosphorus (0.86ppm) and Cation exchange capacity (22.03 cmol(+)/ kg) were observed at higher slope as compare with middle and lower slopes. The deterioration in some chemical properties of lower slope as compared to other slopes were supposed to be due to continuous cultivation for longer period of time and that removed the soil organic matter and other plant nutrients. This study results concluded that increasing extent of continuous and intensive cultivation with minimum conservation practices and erosion due to slope effect can further deteriorate soil properties.
Authors want to thank Assosa University (AU) for its generous financial support covering of all costs of the research work (field work, analysis and printing of the thesis). The staff and faculty of Agriculture and Natural Resource particularly Mr. Bruk Tosheme and Mr. Mathos Bekele deserve appreciation for untiring support and encouragement. Special thanks to the Assosa and Bahridar soil Laboratory for their support.