Abstract
Soil acidification is a major global issue that reduces crop yields and degrades agroecosystems, impacting a significant portion of arable land. In Ethiopia, a large portion of arable land is affected by soil acidity, which limits nutrient availability and threatens agricultural productivity. Addressing this problem requires urgent and effective amendment strategies. This study focuses on evaluating the effects of lime and coffee husk vermicompost (CHVC) on soil physicochemical properties and phosphorus availability, offering potential solutions to mitigate soil acidity in Ethiopia. The soils were collected from croplands in the Sayo District of western Ethiopia. A pot-based incubation experiment was conducted using a factorial combination of three levels of lime (0, 50 and 100% of LR) and three levels (0, 3 and 6 ton/ha) of CHVC. The sole application of lime significantly increased soil pH (H(2)O) from 4.74 to 5.78 in Nitisol and 5.05 to 5.91 in Cambisol. The combined application of 100% LR and 6 t ha⁻¹ of CHVC further enhanced pH (H(2)O) to 6.02 in Nitisol and 6.21 in Cambisol. This combination also significantly reduced exchangeable acidity by 86% in Nitisols (from 3.02 to 0.42 cmolc/kg) and by 88% in Cambisols (from 2.22 to 0.27 cmolc/kg) compared to the control. Additionally, the integrated application of 100% LR and 6 t ha⁻¹ of CHVC consistently increased available phosphorus, from 3.37 to 5.86 mg/kg in Nitisol and from 5.65 to 9.67 mg/kg in Cambisol. The combined use of lime and CHVC also improved soil organic matter content, total nitrogen, exchangeable bases, and cation exchange capacity, demonstrating their potential to enhance soil fertility. However, these amendments led to a reduction in extractable micronutrients (Fe, Mn, Zn, and Cu) in both Nitisols and Cambisols. These results indicate that the combined application of lime and CHVC is highly effective in ameliorating soil acidity and enhancing the availability of phosphorus, along with other essential macronutrients such as nitrogen, potassium, magnesium, and calcium. To validate the practical benefits of these amendments under real-world conditions, further field experiments with test crops are recommended.