Objectives The nitrogen (N) management for potato production was optimized and verified, based on the Nutrient Expert System (NE), to provide a scientific and simple method for potato N fertilizer recommendation.

Methods Potato field positioning experiments were carried out simultaneously in Gansu, Heilongjiang provinces and Inner Mongolia Autonomous region from 2017 to 2020. Based on the NE N application rate (180–186, 180, and 178–240 kg/hm², respectively), four N fertilizer treatments were set up in Gansu, six in Heilongjiang and five in Inner Mongolia. The potato tuber yield, N uptake, N use efficiency, soil mineral N content, urease activity were measured.

Results The potato yield with the N rate was fitted well by univariate conic model. The NE treatment elicited the highest potato yield and N uptake in Gansu, Heilongjiang, and Inner Mongolia. When the N application rate exceeded the NE treatment, the yield decreased significantly. Soil mineral N content increased significantly with increasing N application rate, and urease activity increased at first and then decreased with increasing N application rate, and higher mineral N content and urease activity could be obtained by NE treatment at each experimental site. The cumulative recovery rate of N fertilizer and agronomic efficiency decreased significantly with increasing N application rate. The four-year cumulative N fertilizer recovery rates of NE treatment in Gansu, Heilongjiang, and Inner Mongolia were 39.2%, 55.1%, and 53.1%, respectively, and each accumulated agronomic efficiency was 57.9, 87.6, and 68.3 kg/kg, respectively. Compared with the treatments with higher N rate, the N recovery rates and agronomic efficiencies were significantly increased by 12.5, 21.8 and 21.3 percentage points and 27.0, 37.2 and 30.4 kg/kg, respectively. There was a significant positive correlation between N apparent balance and N application rate, and the accumulated N input and expenditure in the four years of NE treatment tended to be balanced. The regression analysis of univariate conic model showed that the N application rates for the maximum yield in Gansu, Heilongjiang and Inner Mongolia were 186, 199, and 231 kg/hm², respectively, and the N application rates for the optimum economic yield were 165, 188, and 214 kg/hm², respectively.

Conclusions The nitrogen application rate recommended by Nutrient Expert system does not only lead to high yield of potato, but also culminate into higher nitrogen use efficiency and economic benefits, and reduce the risk of N loss by reducing soil N surplus. It is proved that fertilization recommended by Nutrient Expert system can achieve high yield and efficiency of potato production in the mono cropping area of northern China.