Synergizing potato productivity and environmental performance with Nutrient Expert recommendation approach in northern China

Lack of evidence-based fertilizer recommendation has resulted in low productivity and nutrient use efficiency as well as nitrogen (N) pollution for potato in northern China. An innovative nutrient recommendation approach, Nutrient Expert (NE), has been developed for potato through adoption of 4R (applying the right nutrient source at the right rate, time, and place) nutrient stewardship technologies. However, large-scale evaluation of NE on improving potato productivity while minimizing environmental risks are not yet available. Here, we compared the performance of NE with farmers' practice (FP) and soil test (ST) based fertilizer recommendations in 38 potato farm fields in five provinces of China from 2017 to 2020. Compared to FP, NE significantly increased potato yield by 7% with 21% less N input, reduced N balance and N loss by 48% and 31%, and improved nutrient use efficiencies. Compared to ST, NE significantly reduced N input by 19 kg ha−1 without yield and profit losses, and decreased N balance and N losses by 27% and 13%, respectively. Based on a linear relationship between N balance and N application rate, the N application thresholds of 179–191 kg ha−1 were obtained to increase tuber yield and minimize N losses. The NE based N recommendation rate (182 kg ha−1) was within the range of N application thresholds, indicating the synergistic effect of NE on productivity and environmental performance. The NE tool could potentially be expanded to help achieve synergistic yield and environmental improvements in other potato production regions.