Fanya Juu terraces improve soil properties of cultivated land in erosion-prone semi-arid area of Ethiopia

Soil erosion is a major process that affect soil fertility and agricultural productivity. To reduce soil erosion by water, physical soil and water conservation measures such as Fanya juu have been widely introduced. However, the study on the performance of those measures against its target is limited. Objective of this study was to assess the effects of physical soil and water conservation (SWC) measures (e.g., Fanya juu) on selected soil physico-chemical properties. Soil samples were collected at 0-20 cm depth of fields treated with Fanya juu and non-treated (without any physical SWC) and analyzed following standard laboratory procedures. Paired sample t-test and one-way ANOVA were used to analyze data. The results of the analysis revealed that clay, silt, sand, soil pH, soil organic carbon (SOC), total nitrogen (TN), available phosphorous (Pav.), and available potassium (Kav.) differed significantly (p < 0.05) between 8-years conserved and non-conserved land. This could be due to the positive effect of conservation measures in reducing erosion. In addition, in the intra- Fanya juu areas clay, sand, Kav., TN, and SOC were significantly varied (p < 0.05), with greater clay, SOC and nutrients at above Fanya juu (deposition area) than below Fanya juu (loss zone), which can be due to the downward movement of organic matter and surface soil and the protection ability of Fanya juu against erosion. In erosion-prone areas, lacking physical SWC measures could degrade essential soil properties as compared to farm fields with physical SWC measures. The spatial variation in intra-Fanya juu area should be amended by integrating additional soil fertility management practices for better effect.