NITROGEN-FERTILIZATION OF IRRIGATED RUSSET POTATOES IN SOUTH-CENTRAL ALASKA

Allagash Russet, BelRus, Frontier Russet, HiLite Russet, Russet Norkot ah and Russet Burbank were evaluated with preplant N fertilizer levels of 0, 67, 134, 201, and 201 kg N/ha in a split application on a Knik silt loam in 1990 and 1991 near Palmer, Alaska. BelRus and Russet Nork otah yielded less marketable tubers than the other cultivars and Russe t Burbank performed well under warm, dry 1990 conditions and poorly wh en conditions were cool and wet (1991). Allagash, HiLite and Frontier Russets were consistent producers with marketable tuber yields averagi ng 35.4, 32.3, and 32.2 t/ha, respectively Marketable tuber yield was maximized with approximately 175 kg total N/ha (residual soil plus app lied) and approached 43 t/ha in 1990. Splitting the N application had no significant effect on tuber yield. Newly released russets appear pr omising for commercial Alaska producers.