Nitrogen fertilizer on storage life of short-day onion

ABSTRACT

Factors affecting storage of onion (Allium cepa L.) include cultivar, fertilization during production, and length of storage which generally are not complementary. A field experiment with the short-day onion cvs. Mata Hari (red), Mikado (yellow), Cristalina (white), and Star5516 (yellow), and nitrogen (N) applied at 0, 30, 60, 90, 120, or 180 kg ha⁻¹ were used to determine effects on storage loss of onion bulbs. After harvest, 30 well-cured onion bulbs were selected from treatments and replications and stored at room temperature (20–25°C). Storage moisture loss and disease occurrence were recorded on a weekly basis for 120 days. The N level did not affect bulb storage loss and incidence of black mold caused by Aspergillus niger. Storage loss was affected by cultivar, with ‘Cristalina’ and ‘Mikado’ having overall low, 1.22% and 1.36%, respectively storage loss; ‘Mata Hari’ had the lowest storage loss (0.28%). ‘Mikado’ had higher overall storage loss within the first 4 weeks. Black mold development differed over time on ‘Cristalina,’ ‘Star5516,’ and ‘Mikado,’ with higher incidence after 13 weeks of storage. ‘Mata Hari’ had the lowest incidence of black mold over time with only 0.83% by the 13th week of storage. Overall, the amount of N applied to onions had no effect on moisture loss and storability of short-day onions.

KEYWORDS:

• Allium cepa
• soil nitrogen
• cultivar
• black mold

Additional information

Funding

The authors thank the Department of Rural Development and Land Reform, South Africa for financial support.