degradation is recognized as one of the most serious environmental problems in Ethiopia. Hence, assessing the effect of soil erosion on soil fertility and the effectiveness of physical soil and water conservation structures factors that influence the land management practices are of paramount importance for promoting soil fertility and achieve food security. Therefore, this study is to assess the farmers’ perception on erosion problems and factors affecting the physic-chemical properties of soils and crop yields. The watershed chosen was Gola micro watershed located SNNPR of Gamo Gofa zone, Oyda woreda. The study employed questionnaire survey and soil sampling for laboratory analysis to quantify the effect of soil erosion on crop yields and soil physical and chemical properties. Within the study woreda, 150 sample households were selected to questionnaire survey to capture the assessment of soil erosion effect on soil properties and effectiveness of conservation practices employed. The sample households were disaggregated into model and non-model farmers as the degree of adoption of conservation measures is variable. In parallel, -farm fields were selected in the upper, middle and lower stream of the watershed for soil sampling for laboratory analysis. From the Gola micro watershed 12 composite samples were collected from a depth 0-30 cm. The soil samples were analyzed at Holeta Agricultural research to determine selected physical and chemical properties including texture, pH, organic carbon, total N, exchangeable bases and CEC. The data was presented in tables and analyzed in terms of percentage and frequency. The result showed that farmers were aware of the effect of soil fertility loses on crop yields and they have employed a range of soil conservation measures. However, lack of labor and capital to maintain conservation structures made their efforts less effective and erosion is still imposing a major thereat on crop yields. The laboratory analysis have shown that erosion losses have significantly affected chemical properties such as soil (pH), organic matter content and the macro nutrients (N, available P and exchangeable bases). Key Words: Soil erosion, Conservation, crop yield, treated and untreated.