Browsing by Author "BADEGE AYELE"

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    GROWTH AND BULB YIELD RESPONSE OF ONION (Allium cepa L.) VARIETIES TO VARYING LEVELS OF NITROGEN AND VERMICOMPOST IN BIISHAAN GURACHAA, OROMIA, ETHIOPIA
    (Hawassa University College of Agriculture, 2025) BADEGE AYELE
    Onion is a vital horticultural crop in Ethiopia, supporting both rural livelihoods and urban food systems. However, its productivity remains low due to poor nutrient management, declining soil fertility, and continued reliance on unimproved varieties. Excessive nitrogen use often results in delayed maturity and reduced bulb quality, while organic inputs like vermicompost remain underutilized. This study was conducted to evaluate the combined effects of nitrogen and vermicompost on the growth, yield, quality, and economic performance of improved onion varieties under highland conditions. A field experiment was carried out during the off-season at Shallo Farm, using a randomized complete block design (RCBD) with three replications. Treatments were arranged in a 3 × 4 × 3 factorial combinations comprising three onion varieties (Rio Bravo f1, Nafis, and SV Runagrana f1), four nitrogen rates (0, 75, 150, and 225 kg N ha⁻¹), and three vermicompost levels (0, 5, and 7 t ha⁻¹), giving 36 treatment combinations. Data were collected on phenology, growth, yield, and bulb quality parameters, and subjected to both agronomic and economic analyses. The three-way interaction among variety, nitrogen, and vermicompost significantly (P < 0.01) influenced most growth, yield, and quality traits. SV Runagrana f1 exhibited the best performance, producing the highest total bulb yield (57.48 t ha⁻¹) and marketable yield (51.13 t ha⁻¹) at 225 kg N ha⁻¹ combined with 7 t ha⁻¹ vermicompost. Excessive fertilization (>225 kg N + 7 t VC ha⁻¹) increased unmarketable yield, delayed maturity, and lowered bulb quality. Economic analysis further revealed that SV Runagrana f1 at 225 kg N + 7 t VC ha⁻¹ provided the highest net field benefit (4,471,000 Birr ha⁻¹), benefit–cost ratio (35.1%), and marginal rate of return (15,000 %), indicating strong profitability despite higher input costs. In contrast, moderate fertilization (75 kg N + 5 t VC ha⁻¹) offered a favorable trade-off between yield stability, quality, and input efficiency, making it a more sustainable option for smallholder farmers. Therefore, the study demonstrated that onion yield, quality, and economic returns are highly dependent on the interaction between genotype and nutrient management.Further studies should investigate long-term soil fertility effects and validate the economic sustainability of these practices across diverse agro- ecological zones.