Input data set: N-Fertilizer GGCMI (ISIMIP3b)

The n-fertilizer-ggcmifert dataset provides an alternative crop-specific nitrogen fertilizer forcing for a dedicated ISIMIP3b sensitivity experiment. It was developed to investigate the sensitivity of crop model simulations to the representation of fertilizer inputs by preserving observed spatial patterns of fertilizer application while following the temporal evolution projected by Integrated Assessment Models.

The dataset provides annual, crop-specific nitrogen fertilizer application rates on a global grid for use in the ISIMIP3b "ggcmifert" sensitivity experiment. It differs from the standard ISIMIP3b Group III fertilizer forcing, which directly applies fertilizer application rates from the Integrated Assessment Models (IAMs), by employing a harmonization procedure that preserves observed spatial patterns of fertilizer use.

Historical and future fertilizer application rates are generated by combining the crop-specific, spatially explicit fertilizer maps of Mueller et al. (2012) for the reference year 2000 with temporal changes derived from the MAgPIE and IMAGE Integrated Assessment Models. The harmonization algorithm preserves the sub-national spatial variability of fertilizer application, reflecting differences in crop productivity and management intensity, while adopting the temporal evolution projected by the IAMs. Depending on the magnitude of the bias between the IAM and the reference data in the year 2000, the temporal evolution is applied as either an absolute or relative change, with a smooth transition between both approaches. This methodology preserves projected trends while avoiding unrealistic fertilizer application rates in regions where the IAMs substantially underestimate fertilizer use in the reference year.

As in the standard ISIMIP3b setup, annual fertilizer application rates are limited to a maximum of 500 kg N ha⁻¹ yr⁻¹.

The dataset contains separate annual fertilizer application fields for the following crop types:

cas (cassava)
mai (maize)
mil (millet)
nut (nuts)
pea (peas)
rap (rapeseed)
ri1 (rice, first growing season)
ri2 (rice, second growing season)
sgb (sugar beet)
sgc (sugar cane)
sor (sorghum)
soy (soybean)
sun (sunflower)
swh (spring wheat)
wwh (winter wheat)

Future projections are provided for each combination of the five ISIMIP core climate models and the two Integrated Assessment Models, MAgPIE and IMAGE, following the ISIMIP3b Group III adaptation scenarios. This dataset is intended exclusively for the ggcmifert sensitivity experiment and should not be used as a replacement for the standard ISIMIP3b fertilizer forcing.

The dataset was originally developed for use within the Global Gridded Crop Model Intercomparison (GGCMI) and is subsequently adopted by ISIMIP for an ISIMIP3b nitrogen-fertilizer sensitivity experiment.

Works cited:

Heinke, J., Ostberg, S., Schaphoff, S., Frieler, K., Müller, C., Gerten, D., Meinshausen, M., and Lucht, W.: A new climate dataset for systematic assessments of climate change impacts as a function of global warming, Geosci. Model Dev., 6, 1689–1703, https://doi.org/10.5194/gmd-6-1689-2013, 2013.

Mueller, N. D. et al. Closing yield gaps through nutrient and water management. Nature 490, 254–257, https://doi.org/10.1038/nature11420 (2012).

Sam Rabin & Christoph Müller. (2026). AgMIP-GGCMI/fertilizer_rates: v1.0.1 (Version v1.01) [Computer software]. Zenodo. https://doi.org/10.5281/zenodo.21496984

For ISIMIP participants, these files are available for download on the DKRZ server:
/work/bb0820/ISIMIP/ISIMIP3b/InputData/socioeconomic/n-fertilizer-ggcmifert/