Petiole analysis and the nitrogen fertilization of Russet Burbank potatoes

The effect of nitrogen rates on the yield of Russet Burbank potatoes was studied in field experiments in Idaho. Petioles were sampled at the 6-to-8 leaf stage and thereafter at two week intervals until mid August. Petiole nitrate concentrations were very high early but decreased rapidly as the season progressed and declined to a very low level as the plants matured. The nitrate content of the petioles reflected the amount of N applied to both locations. Nitrogen applications increased total yield and the quantity of the larger size tubers. A highly significant correlation was found between the early season petiole nitrate concentrations and total yield. Suggested ranges of petiole nitrate concentrations were developed as a guide to efficient N fertilization of Russet Burbank potatoes in Idaho.