Study the effects of different source and amounts of nitrogen fertilizer on characteristics of two onion cultivars

• Main Authors: Samavat, Saeed, Baybourdi, Ahmad, Rostamforodi, F, Khiri, Kazem, Kahbazi, Majid
• Format: Publication
• Language: Persian
• Published: Tehran (Iran) Soil and Water Research Institute - SWRI 2007
• Subjects: ABONOS; ABONOS NITROGENADOS; AMIDAS; AMIDE; AMIDES; AMMONIUM; AMMONIUM COMPOUNDS; AMMONIUM NITRATE; AMONIO; Azarbijan (Province); AZOTE; AZUFRE; CALIDAD; CEBOLLA; COMPOSE DE L'AMMONIUM; COMPUESTOS DE AMONIO; CONSUMER PROTECTION; CONTROL DE CALIDAD; CONTROLE DE QUALITE; ENGRAIS; ENGRAIS AZOTE; FERTILIZERS; HORTALIZAS; IRAN ISLAMIC REPUBLIC; IRAN REPUBLICA ISLAMICA; IRAN REPUBLIQUE ISLAMIQUE; Karaj (Iran); LEGUME; METALLOIDE; NITRATE; NITRATE D'AMMONIUM; NITRATES; NITRATO DE AMONIO; NITRATOS; NITROGEN; NITROGEN FERTILIZERS; NITROGENO; NO METALES; NONMETALS; OIGNON; ONIONS; PROTECCION DEL CONSUMIDOR; PROTECTION DU CONSOMMATEUR; QUALITE; QUALITY; QUALITY CONTROLS; Red Rey; RENDEMENT; RENDIMIENTO; SOUFRE; SULPHUR; TAXA; TAXON; UREA; UREE; VARIEDADES; VARIETE; VARIETIES; VEGETABLES; White Qum; YIELDS

A randomized complete block factorial experiment was carried out in East azarbyjan province and karaj rejoin during 2003-04 in order to study the effects of rates and source of nitrogen fertilizers on the yield and quality of two onion varieties . The first factor consisted of four nitrogen levels (N1=60.N2=120.N3=180.N4=240 Kg N/ha) and the second factor consisted of four different sources of nitrogen, namely: S1=urea ,S2=ammonium nitrate ,S3= sulfur coated urea, and S4= urea-formand the third factor consisted of two varieties of onion , namely , White Qum and Red rey . In Azarbiejan the experimental plots were located at khosrow shar agr. research Station. The results revealted that there were no significant yield differences observed between N180 and N240 treatment levels . In relation to the effects of nitrogen sources, the greatest yield was obtained with urea-form , but no significant differences were obtained between sulfur coated urea , urea form and ammonium nitrate treatments. Urea - form and sulfur coated urea fertilizers performed considerably better than urea.The best yield of 78 T/ha of white Qum onions was obtained with the application of 240 kgN /ha . The white Qum onion variety yielded higher than Red Rey onions. The greatest rate of onion spoilage was observed with nitrogen at the rate of N240 . With respect to nitrogen sources, urea produced the highest rate of spoilage.The Red Rey onion produced more total soluble solids. The red onion contained the highest nitrate concentrations resulting from nitrogen rate of N240 . As with the effect of variety, the highest nitrate concentration of 410 mg/kg was measured with white Qum as compared with the Red Rey variety. The longest bulb was obtained with nitrogen rate of N240. The sharpest taste based on pyruvic acid concentrations was also obtained with the nitrogen rate of N240 . Similary, sulfur coated urea produced the sharpest taste. The Red Rey onions produced sharper taste than the Qum variety. Finally, the largest onions resulted from the nitrogen rates of N240 and N180. At karaj agr. Research station the highest yields was obtained from S3N4 treatment and had significant differences at 5% level with respect to control and other treatments. The yields of all treatments in year of 2004 was higher than with respect to 2003. The main effects of nitrogen sources on onion nitrate in both varieties were not significant, but the concentration of nitrate in urea treatment was some what lower than other treatments. The use of slow release nitrogen fertilizer accumulated more nitrate concentration in onions bulbs. Finally the accumulation of nitrate in Red Rey was less than white Qum variety.