نوع مقاله : مقاله پژوهشی
نویسندگان
1 عضو عیأت علمی مرکز تحقیقات کشاورزی آذربایجانشرقی
2 استاد دانشگاه تربیت مدرس
3 عضو هیأت علمی موسسه تحقیقات خاک و آب
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
A randomized compete block factorial experiment was carried out in East Azarbyjan province during 2003-04 in order to study the effects of rates and sources of nitrogen fertilizers on the yield and quality of two onion varieties. The first factor consisted of four nitrogen levels (50, 120, 180 and 240 kgN/ha) and the second factor consisted of four different sources of nitrogen, namely, urea, ammonium nitrate, sulfur coated urea, and urea-form; and the third factor consisted of two varieties of onions, namely, Qum Red and White Rey. The experimental plots were located at Khosrow Shahr Agr. Res. Station with the soil series as Fine mixed calcareous fluventic exerothents. The results revealed that there were no significant yield differences observed between N180 and N240 treatment levels. In relation to the effect of nitrogen sources, the greatest yield was obtained with urea-form, but no significant differences were obtained between sulfur coated urea treatment, urea form and ammonium nitrate treatment . Urea-form and sulfur coated urea fertilizers performed considerably better than urea. The best yield of 78 tons/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 420 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. Similarly, 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.
کلیدواژهها [English]