Comparative Effects of Biochar, Wood Ash, and Lime on the Chemical Properties of Acidic Clay Loam Soils at Segno Gebeya, Legambo District, Northeastern Ethiopia

Abstract

<title>Abstract</title> Soil acidity severely limits crop productivity in the Ethiopian highlands due to nutrient depletion and low soil fertility. This study examined the impact of Biochar, wood ash, and lime on the chemical properties of acidic clay loam soils in Segno Gebeya Kebele, Legambo District, Northeastern Ethiopia. A 3 × 4 factorial experiment was conducted using a randomized complete block design with three replications. The amendments were applied at rates of 0, 5, 10, and 15 t ha⁻¹. Soil samples (0–20 cm) were analyzed before and after treatment for pH, organic carbon (OC), total nitrogen (TN), available phosphorus (AvP), cation exchange capacity (CEC), exchangeable bases, electrical conductivity, and organic matter (OM). The initial soil was strongly acidic (pH 4.10) and nutrient-deficient. All amendments significantly improved soil chemical properties compared to the control. Lime and Biochar were most effective in raising soil pH, while wood ash showed moderate effects. Lime increased exchangeable Ca²⁺ and OM, Biochar enhanced OC, K⁺, and CEC, and wood ash improved Mg²⁺, TN, and AvP. Application rates of 5–10 t ha⁻¹ were optimal, as higher rates showed diminishing returns. Overall, integrating these amendments can sustainably enhance soil fertility in acidic highland soils of Ethiopia.