Interaction of Planting Distance and Fertilizer Dose on the Growth and Yield of Welsh Onion (Allium fistulosum L.)

Abstract

Welsh onion production in the highlands generally fluctuates due to suboptimal cultivation practices, specifically in planting distance and fertilization. This research aims to determine the effect of planting distance, doses of chicken manure organic fertilizer and NPK, and their interactions on the growth and yield of Welsh onions in the highlands. The research was conducted in Insil Village, Passi Timur Subdistrict, Bolaang Mongondow Regency, North Sulawesi, from February to May 2026. The method used was a two-factor factorial Randomized Complete Block Design (RCBD). The first factor was planting distance consisting of 20×20 cm and 30×30 cm. The second factor was fertilizer dose consisting of 10 tons/ha organic fertilizer + 300 kg/ha NPK, 15 tons/ha organic fertilizer + 450 kg/ha NPK, and 20 tons/ha organic fertilizer + 500 kg/ha NPK. Observational data were analyzed using analysis of variance (ANOVA) followed by a 5% LSD test. The results showed that planting distance independently had a significant effect on plant height, leaf number, tiller number, and stem diameter. The application of organic fertilizer and NPK independently had no significant effect on all observed parameters. There was a significant interaction between planting distance and fertilizer dose on plant height, leaf number, tiller number, and plant fresh weight. In conclusion, the combination of a 30×30 cm planting distance with 10 tons/ha of organic fertilizer and 300 kg/ha of NPK (J2P1) provided the best growth and yield responses compared to other combinations.