Agronomic and Physiological Response of Potato (Solanum tuberosum L.) to Nitrogen Fertilization Rate on a Loess Soil of Northwest China

The tuber yield of potato in China is relatively low compared to the average global yield, partly due to poor nitrogen (N) management. Moreover, excessive N fertilization reduces the nitrogen use efficiency (NUE) of potato and increases production costs, which reduces profit margins. Therefore, a 2-year field trial was conducted on an existing field with 5 years of different inorganic N fertilization rates in Dingxi to determine the effects of N fertilization rate on growth, tuber yield, net income and NUE of potato on a loess soil. The experiment included six N fertilization rates, namely 0 kg N ha(-1) (N0), 75 kg N ha(-1) (N1), 150 kg N ha(-1) (N2), 225 kg N ha(-1) (N3), 300 kg N ha(-1) (N4) and 375 kg N ha(-1) (N5). The treatments were laid out in a randomized complete block design and replicated four times. The results from the principal component analysis revealed that N fertilization has a strong effect on potato growth, tuber yield and NUE. Treatment N2 increased total tuber yield (29.0% and 33.1%) and net income (54.8% and 61.4%) of potato in 2018 and 2019 seasons, respectively, compared to the control. Excessive N fertilization (N5) reduced tuber yield, net income and NUE of potato in both seasons. To increase tuber yield, net income and NUE of potato (cultivar Qingshu 9) on a loess soil of Northwest China, N fertilization rate should not exceed 150 kg ha(-1).

Automated summary

The tuber yield of potato in China is relatively low due to poor nitrogen management. Excessive nitrogen fertilization reduces nitrogen use efficiency and increases production costs, resulting in lower profit margins. This study found that an appropriate nitrogen fertilization rate can increase potato yield and net income. For the Qingshu 9 cultivar grown on loess soil in Northwest China, the nitrogen fertilization rate should not exceed 150 kg/ha.