Growth and Yield Performance of Shallot (Allium ascalonicum L.) under Basal NPK 15-15-15 Fertilization on Ultisol

¹ Agroecotechnology Program Study, Department of Agricultural Cultivation, Faculty of Agriculture, Universitas Sriwijaya,
² Agronomy Program Study, Department of Agricultural Cultivation, Faculty of Agriculture, Universitas Sriwijaya
³ Soil Science Program study, Department of Soil Science, Faculty of Agriculture, Universitas Sriwijaya,

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract

This study evaluated the growth and yield performance of shallot (Allium ascalonicum L. cv. Bima Brebes) cultivated on Ultisol under basal application of NPK 15-15-15 fertilizer. The study was conducted on field plots measuring 1.5 m × 5 m at the Experimental Field of Universitas Sriwijaya, Indralaya. Initial soil analysis indicated clay texture, blocky structure, slightly acidic pH (5.7), low total nitrogen (0.11%), and low total potassium (15 mg 100 g⁻¹), despite high organic carbon content (3.64%). Vegetative growth showed a maximum plant height of 27.5 cm and 13 leaves at 5 weeks after planting (WAP). Yield components recorded a fresh bulb weight of 19.21 g, dry bulb weight of 17.90 g, and productivity of 5.4 t ha⁻¹. The results indicate that shallot is able to grow under Ultisol conditions with basal NPK fertilization; however, the yield obtained remains below the varietal potential of 8–15 t ha⁻¹. This confirms that soil constraints, particularly low potassium availability and soil acidity, still limit yield performance. Further improvement through potassium supplementation and pH management is required to increase productivity.