Comparison of Fusn and Urea Fertilizers on Potato Yield and Tuber Quality in SE Idaho.

Efficient N management is an essential part of any potato fertilization program. Nitrogen management can affect potato yield and tuber size and shape, as well as many other tuber quality factors. FUSN is a relatively new, dry granular ammonium sulfate nitrate fertilizer made from a patented process that chemically fuses ammonium sulfate and ammonium nitrate to produce an entirely new and highly stable molecule, a 26-0-0 14S fertilizer. Two trials were conducted at Rexburg, ID in 2015 on Russet Burbank and Russet Norkotah potato cultivars. FUSN was compared to urea at three rates. There was no response to N beyond the lowest rate of 70 lb-N/ac. and, therefore, the yields at this lowest rate of N fertilization were compared. FUSN resulted in increases for US No. 1 and total yield in all cases, with the increase being significant for Russet Norkotah. It is also noteworthy that the petiole NO₃-N concentrations were consistently lower for FUSN vs. urea at the lowest rate of N, possibly due to added growth of the plants and a dilution effect. Tuber size was numerically higher for FUSN, although not statistically significant. These data show that FUSN does not result in any negative impacts when used in place of urea and may possible result in better tuber quality.