In this experiment five sugar beet mono-germ cultivars were evaluated in Peruvian arid northern coast. Work was made in Alluvial soils (Entisols) highly saline (5.38 to 22.5 dS m-1), located at sugar cane Casa Grande enterprise where normally not a single crop develops. Experiment was done in a blocks complete randomized design with five treatments and 20 replications. Irrigation was with well water, and fertilization was with urea (180 kg ha-1 of N). N gains and loses balance shows that 421 kg ha-1 of N are incorporated to soil and 374 kg ha-1 of N are lost. Gains wins to lost in 47 kg ha-1 of N. Furthermore it was found that in these marginal soils, highly saline, sugar beets produce high root yields (81.69 t ha-1) for sugar o alcohol production and high leafs and crowns yields (40.77 t ha-1) for livestock aliment.