The NBCalCer model for calculating global benefits and costs of nitrogen fertilizer use for cereal cultivation: Model description, uncertainty analysis and validation

• NBCalCer estimates effects of nitrogen on yields and environment in global cereals. • Crop benefits and environmental damages are monetized at the country scale. • NBCalCer provides several integrated performance indicators for cereals systems. • NBCalCer helps navigate policies reconciling food security and environment. • Results plausibility and policy potential of the model are demonstrated. The challenge of achieving food security in a world with a growing population, given decreasing area of good arable land, and climate change impacts, necessitates structural system changes which includes a more efficient and less polluting agricultural practices. Cereals represent the major staple crop to feed the global population, and its production heavily relies on synthetic nitrogen (N) fertilizers. However, increasing fertilizer inputs for higher yields is not sustainable without proper management of soil, crop, inputs, water and nutrients. The NBCalCer tool was developed to evaluate options for a more sustainable cereal cultivation. NBCalCer quantifies long-term yield responses to N inputs and its implications for N budgets, N losses and environmental impacts for global countries. Crop benefits and environmental damages are monetized to assess benefit-cost consequences for the farming sector and society, to determine optimal N inputs for both sufficient grain supply and acceptable N pollution levels.