Effect of Swiftlet (Aerodramus fuciphagus) manure on growth and yield of shallots in Ultisols

Abstract

Shallots (Allium cepa var. aggregatum) are an essential horticultural crop in Indonesia for domestic use and export. Their productivity is influenced by soil fertility, with Ultisol, posing challenges due to low fertility. Swiftlet manure, rich in nutrients, has the potential as an organic amendment to improve soil conditions and enhance crop yield. This study examines the effect of different doses of swiftlet manure on the growth and yield of shallots in Ultisols. The study was conducted from August to October 2023 in Pondok Suguh Village, Pondok Suguh Subdistrict, Mukomuko Regency, Bengkulu. The experiment used a Completely Randomized Design (CRD) with a treatment of swiftlet manure, consisting of 0 tons/ha (control), 5, 10, 15, 20, 25, and 30 tons/ha, combined with synthetic N, P, K fertilizers at half of the recommended dose. The recommended dose for synthetic fertilizer was 435 kg/ha urea, 250 kg/ha SP-36, and 125 kg/ha KCl. Data were analyzed using Analysis of Variance (ANOVA) at the 5% significance level and the treatment means were separated using Duncan's Multiple Range Test (DMRT) at the 5% level. The study showed that the plant height and leaf number of shallots at various doses of swiftlet manure tended to increase, producing taller plants and more leaves compared to the control. Swiftlet manure at doses of 20, 25, and 30 tons/ha resulted in no significant differences in plant height, leaf number, fresh weight, and dry weight of bulbs. Swiftlet manure at a dose of 20 tons/ha produced 7.5% and 15.5% higher fresh bulb weight and 19.3% and 18.1% higher dry bulb weight than at 25 and 30 tons/ha doses, respectively. This finding supports sustainable agriculture practices in shallot cultivation.