Selected physical and chemical properties of soil under different agroecological zone in Gedeo Zone, Southern Ethiopia

Soil fertility is the ability of the soil to provide favorable chemical, physical and biological characteristics to sustain plant growth. Its physicochemical properties are greatly influenced by altitude and farmer wealth status. This study aimed to examine the differences in selected soil physicochemical properties under three agroecological zone based on altitude gradient (upper, middle, and lower) and wealth class (rich, medium, and poor) in the organic agriculture dominant area of the Gedeo zone, southern Ethiopia. Soil samples were collected from the field under organic agriculture. A total of 216 composite soil samples 3(altitude) 12 (wealth class) 3(replication) and 2 soil depth (0–30 and 30–60 cm) were collected and analyzed for some selected soil physical and chemical properties using standard soil analytical procedures. Data were subjected to a two-way analysis of variance to determine the effects of agroecological zones and wealth status of households on the soil properties. The result showed that soil physical properties such as sand (p < 0.01), clay (p < 0.05) and bulk density (BD) (p < 0.01) were significantly affected by altitudinal gradients. Soil organic carbon (SOC), cation exchange capacity (CEC), total nitrogen (TN) and phosphorus (P) were in the suitable range for agricultural soil, suggesting that the organic agricultural practices employed in the study area might be contributed to improved soil fertility. Soil pH (H(2)O, (p < 0.01), CEC (p < 0.05), SOC % (p < 0.001), TN % (p < 0.05), P(p < 0.001) and K (p < 0.05) were significantly varied due to difference in agroecological zone. Similarly, wealth class of farmer had significant influence on soil pH (H(2)O) (p < 0.001), SOC (p < 0.001) and P (p < 0.001). The results highlight the importance of the agroecological zone and wealth status of farmer households on soil fertility improvements in the study area. Hence, during the implementation of the soil fertility policy, considering the altitude and wealth status of the farmer is recommended to improve soil fertility.