Optimasi Jarak Tanam Dan Dosis Pupuk NPK Untuk Produksi Bawang Merah Dari Benih Umbi Mini Di Dataran Tinggi

. Sumarni, N, Rosliani, R, and Suwandi 2012. Optimization of Plant Distance and NPK Dosage to Produce Shallots from Shallots Set in Highland. Shallots set is small seed bulb derived from true shallot seeds (TSS). Using of the shallots set in shallots production is not common yet in Indonesia. The objective of this research was to find out the optimum plant distance in combination with NPK dosage to produce shallots bulb from shallots set in highland. The experiment was conducted at the Experimental Garden of the Indonesian Vegetable Research Institute, Lembang (1,250 m asl.) on Andisol soil, from August to December 2009. A randomized complete block design with three replications was applied in the study. There were 12 treatments, viz. three levels of plant distance of 5 x 20 cm, 10 x 20 cm, and 15 x 20 cm that were combined with the application of four levels of standard dosage of NPK, viz. 0.5; 1.0; 1.5; and 2.0 NPK standard dosage, and one treatment as a control using bulb (5 g/set) with 15 x 20 cm planting distance, and a NPK standard fertilization (N 190 kg/ha, P2O5 92 kg/ha, and K2O 120 kg/ha). Bima Brebes cultivar was used as a planting material source for developing TSS, mini bulbs, and bulbs as generally applied in conventional cultivation. Research results revealed that the highest number of bulbed-plant harvested in the experiment 39.10% was recorded on shallots set cultivated using plant distance of 15 x 20 cm and NPK dosage of N 95 kg/ha, P2O5 46 kg/ha, and K2O 60 kg/ha compared to other treatments (14.66–33.22%). The treatment also gave higher results compared to conventional cultivation using bulbs (24.99%). The optimum plant distance and NPK dosage to produce shallots bulb from shallots set in highland was 15 x 20 cm and N 190 kg/ha, P2O5 92 kg/ha, and K2O 120 kg/ha that resulted in 35.48 g dry weight of shallots bulb per plant. The application of shallots set could increase the quantity and quality of shallots yield, and reduced quantity of bulbs needed per hectare