Optimizing Agronomic Technology Package for Soil Fertility and Crop Yield Restoration on the Affected Area of Sinabung Volcano Eruption, Indonesia

The effusive Sinabung Volcano eruption resulting a large negative impact on agricultural land, causing soil acidification and nutrient imbalances, reducing crop productivity and leading to the declining farmers’ income. This study was conducted on the affected area to determine a proper agronomic technology package, to assess changes in soil fertility, potato yield and quality, and to calculate the economic profit of the tested-packages. This study was laid out in a completely randomized design with five agronomic technology packages, combining organic and inorganic fertilizer, lime and sawdust. The result revealed that Package C, applying 20 t manure + 5 t sawdust + 2 t dolomite + 500 kg NPK + 100 kg Urea + 100 KCl per hectare, significantly improved soil fertility, increasing soil pH from 4.5 to 5.3 and enhancing Cation Exchange Capacity and water retention. This package also produced the highest potato yield (39.81 t/ha), which is statistically significant difference with other packages and has the best-quality tubers (grade A to C). Economically, Package C received the highest net benefit and benefit-cost ratio per hectare, by US $ 12.017.4 and 2.70, respectively. In contrast, the farmers‘ practices (Package E) resulted in lower yield, a decline in tuber quality and reduced economic income. These findings demonstrate that the integrated agronomic technology packages, particularly Package C, offer a sustainable and profitable solution for restoring soil fertility and enhancing crop production on the volcanic-affected areas. The study provides some actionable recommendations for farmers and policymakers to support agricultural recovery and resilience in the face of natural disasters.