Potato yield and phosphorus use efficiency of two new potato cultivars in New Brunswick, Canada

Abstract

This 2-yr (2013 and 2014) study evaluated the variation in tuber yield and selected indices of phosphorus (P) use efficiency of two new potato cultivars [AAC Alta Cloud (AC) and AAC Alta Strong (AS)] versus Russet Burbank (RB), the french fry industry standard. Initial P levels and P saturation index [(P/Al) × 100] ranged from 85 to 89.5 mg P kg-1 and from 4.6% to 5.6%, respectively. A complete randomized block design for each variety was laid out in three adjacent plots with six P fertilization rates. The average tuber yield ranged from 29.06 to 36.81 Mg ha-1 for AC, from 27.56 to 41.50 Mg ha-1 for AS, and from 38.15 to 42.02 Mg ha-1 for RB, with the highest yield observed in 2014. Tuber yield response to P application was described by the quadratic-plus-plateau model for AC and linear-plus-plateau model for AS with a mean critical (above which the yield response to P applications is unlikely) P rate of 40 kg P ha-1. Russet Burbank did not respond to P application. The trends of P uptake efficiency (PUE) for AC and AS mirrored that of tuber yield, while RB had a linear increase in PUE with P rate. The study highlights that current P recommendations for potatoes can be reduced without affecting yield, thus increasing farmers’ economic returns. It also reveals the need to test optimal fertilization levels for new cultivars.