Optimasi Jarak Tanam dan Dosis Pupuk NPK untuk Produksi Bawang Merah dari Benih Umbi Mini di Dataran Tinggi - N Sumarni; R Rosliani; - Suwandi (Jurnal Hortikultura, 2012)
ABSTRAK. Benih umbi mini bawang merah (shallots set) adalah benih umbi berukuran kecil (<3 g/umbi) yang dihasilkan dari biji botani bawang merah (True Shallot Seeds). Penggunaan benih umbi mini belum umum dilakukan pada budidaya bawang merah di Indonesia. Penelitian bertujuan mendapatkan jarak tanam dan dosis pemupukan NPK untuk produksi umbi bawang merah dari benih umbi mini di dataran tinggi. Penelitian dilaksanakan di Kebun Percobaan Balai Penelitian Tanaman Sayuran Lembang (1.250 m dpl.) dengan jenis tanah Andisol, dari bulan Agustus sampai dengan Desember 2009. Rancangan percobaan yang digunakan ialah acak kelompok dengan tiga ulangan dan 12 perlakuan, yaitu tiga taraf jarak tanam (5 x 20 cm, 10 x 20 cm, dan 15 x 20 cm), yang dikombinasikan dengan empat taraf dosis pupuk NPK (½ ; 1,0; 1,5; dan 2,0 dosis NPK standar), dan satu perlakuan kontrol yang menggunakan benih umbi konvensional (5 g/umbi) dengan jarak tanam 15 x 20 cm dan 1,0 dosis pupuk NPK standar. Dosis NPK standar ialah N 190 kg/ha, P2O5 92 kg/ha, dan K2O 120 kg/ha. Benih umbi mini dan benih umbi konvensional yang digunakan ialah varietas Bima Brebes. Hasil penelitian menunjukkan bahwa jumlah tanaman yang berumbi (dapat dipanen) paling banyak (39,10%) terdapat pada perlakuan jarak tanam 15 x 20 cm dan dosis pupuk NPK yang rendah (N 95 kg/ha, P2O5 46 kg/ha, dan K2O 60 kg/ha) menggunakan benih umbi mini dibanding perlakuan yang lain (14,66–33,22%). Perlakuan tersebut juga berbeda nyata dibandingkan dengan perlakuan menggunakan benih umbi konvensional (24,99%). Jarak tanam 15 x 20 cm dengan dosis N 190 kg/ha, P2O5 92 kg/ha, dan K2O 120 kg/ha merupakan jarak tanam dan dosis pupuk NPK optimal untuk produksi umbi bawang merah asal benih umbi mini, yang menghasilkan bobot umbi kering eskip sebesar 35,48 g/tanaman. Penggunaan benih umbi mini dapat meningkatkan kuantitas dan kualitas hasil umbi bawang merah, serta mengurangi (tonase) penggunaan benih umbi per satuan luas.  ABSTRACT. 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.