The Effects of ‘<i>Fanya juu’</i> Soil Conservation Structure on Selected Soil Physical & Chemical Properties: the Case of Goromti Watershed, Western Ethiopia

Abstract

Soil degradation is evident in the mountainous areas of Ethiopia, is often represented as results of human pressure. It can be improved through different Soil and Water Conservation (SWC) measures. The study was conducted in Goromti watershed, in western Ethiopia to evaluate the impact of Fanya juu structures on some soil physical & chemical properties. Cultivated fields treated by five years and ten years old fanyajuu structures were compared with non conserved cultivated land (control) and evaluated under three slope gradients. The slope gradients were; gentle (3-15%), moderately steep (15-30%) and steep slope (>30%). A total of 27 soil samples were collected from the top 20 cm soil depth replicated three times and selected physical and chemical properties were analysed in the laboratory. The results of the study showed that soil pH, soil organic carbon (SOC), total nitrogen (N) were significantly (p≤0.05) different on farms treated by the fanyajuu compared to the non-conserved plots as well as under the different slope gradients. Bulk density (Db), sand and clay fractions were significantly varied with slope gradient. Soil organic carbon and total N were higher while bulk density was lower in soil under the non-conserved fields than in fields with fanyajuu structures. But no significant difference was observed in soil bulk density, sand and clay fractions among treatments. Similarly, CEC, available K and available P, and exchangeable K+, Ca2+, and Mg2+ didn’t show any significant differences with respect to structures and slope gradient. The research indicates that structures could benefit farmers through improving the nutrient status better if integrated with agronomic measures by using vegetation suitable for the local environment in one hand, and properly maintained for longer period of time, on the other.