RT Journal Article SR Electronic T1 Nitrogen Fertilization of White Riesling Grapes in Washington. Must and Wine Composition JF American Journal of Enology and Viticulture JO Am J Enol Vitic. FD American Society for Enology and Viticulture SP 34 OP 42 DO 10.5344/ajev.1994.45.1.34 VO 45 IS 1 A1 S. E. Spayd A1 R. L. Wample A1 R. G. Evans A1 R. G. Stevens A1 B. J. Seymour A1 C. W. Nagel YR 1994 UL http://www.ajevonline.org/content/45/1/34.abstract AB Nitrogen (N) fertilizer was applied to White Riesling grapevines through the drip irrigation system at rates of 0, 56, 112, or 224 kg N/ha for three years. Attainment of 21% soluble solids was delayed as rate of N fertilization increased. Juice and wine titratable acid and organic acid concentrations did not vary due to N fertilization rate. Juice pH increased linearly with increasing N fertilizer rate and was related to juice titratable acid and ammonia concentration. Juice potassium concentrations were not affected by N fertilizer rate, while wine potassium concentrations increased linearly with increasing N. Wine pH increased with N fertilizer rate and was related to tartrate and to a lesser extent to potassium concentration. Juice total N, ammonia, free amino nitrogen, arginine, and proline concentrations increased linearly with increasing N fertilizer rate. Wine urea concentrations after four to six years of storage at 15°C was low (highest concentration was less than 10 mg/L), but increased linearly with increasing rate of N fertilization.