Assessment of Fertilizer Use by Crop at the Global Level 2011. Fully understanding the contribution of the different crop types to fertilizer use at national, regional and global levels is a prerequisite to the development of sound fertilizer demand forecasts. IFA gathers information on fertilizer use by crop in the main fertilizer-consuming countries. IFA's Assessment currently covers 23 countries (considering the EU-27 as a single country), which account together for more than 90% of world fertilizer consumption, making it possible to analyze fertilizer use by crop type at the global level.