Nitrogen Use Efficiency of Potato

Abstract

Potato (Solanum tuberosum) production typically occurs on sandy soils with only 40-60% of the applied nitrogen (N) acquired by the crop. Nitrogen fertilization rates in potato are upwards of 336 kg N ha-1. Increased N use efficiency (NUE) and its component parts, N utilization efficiency (NUtE) and N uptake efficiency (NUpE), could drastically reduce fertilizer rates and losses to the environment. We grew 12 advanced breeding selections from the University of Minnesota red potato breeding population and two elite checks under two N rates, 101 kg N ha-1 and 202 kg N ha-1. We compared NUE, NUpE and NUtE in low and high N using 45 day after planting (DAP) root phenotypes and harvest yield and skin quality metrics. We found that NUtE correlated with NUE and yield in low N and NUpE correlated with NUE and yield in high N. Low N favored smaller tubers <6.35 cm in diameter (USDA small), while high N favored tubers between 6.35cm to 8.26cm diameter (USDA medium). Nitrogen did not significantly affect skinning and redness but did significantly affect skin lightness, with low N resulting in slightly lighter skin color. Finally, we found that greater total root mass, stolon root, or basal root, correlated with greater yield and NUE, but did not correlate with measures of N uptake.