Nitrogen budget data

Input-output estimates of nitrogen (N) on cropland are essential for improving N management and better understanding the global N cycle. Here, we compare 13 N budget datasets covering 115 countries and regions over 1961-2015. Though most datasets showed similar spatiotemporal patterns, some annual estimates varied widely among them, resulting in large ranges and uncertainty. In 2010, global medians (in Tg N yr-1) and associated min-max ranges were 73 (64-84) for global harvested crop N; 161 (139-192) for total N inputs; 86 (68-97) for N surplus; and 46% (40%-53%) for nitrogen use efficiency. Some of the most uncertain N budget terms by country showed ranges as large as their medians, revealing areas for improvement. A benchmark N budget dataset, derived from central tendencies of the original datasets, can be used in model comparisons and inform sustainable N management in food systems.