Optimum nitrogen rate to maintain sustainable potato production and improve nitrogen use efficiency at a regional scale in China. A meta-analysis

The great challenges of ensuring global food security and reducing environmental risk caused by excessive fertilizer inputs require optimizing fertilizer rates to maintain crop production and environmental sustainability. Previous results regarding optimizing N-fertilizer rate for potato were mainly based on case studies and lacked regional-scale information on N-fertilizer management. We hypothesized that regional optimum N rates would increase N use efficiency without sacrificing potato yield compared with low and high N rates. We determined the optimal N-fertilization rates for Chinese potato production at a regional scale based on a dataset of 706 observations from 142 peer-reviewed publications. The linear-plus-plateau model was used to estimate regional optimum N rates, which were 115, 150, 120, and 126 kg N ha −1 for the northern, central, southwestern, and southern regions of China, respectively. The target yield could be obtained by applying less N fertilizer when the indigenous N supply was higher across the main potato production region in China. Compared with high N rates, recommended N rates increased N use efficiency and agronomic efficiency by 48.60–81.67% and 17.12–72.90%, respectively, without any yield losses. Recommended N rates also achieved 5.95–14.70% greater yield than low N rates. Here, we show for the first time that, based on a comprehensive literature review, regional optimum N-fertilizer rates result in increased yield and N use efficiency, and reduced negative environmental impacts, all of which play a vital role in maintaining sustainable potato production. The present study highlights the importance of research for achieving a reasonable trade-off between food security and N-fertilizer management for sustainable agriculture.