| AQUASTAT | FAO's global information system on water and agriculture | 
| FAOSTAT | Food and Agriculture Organisation | 
| GCMD | Global Change Master Discovery (NASA) | 
| HWSD | Harmonized World Soil Database | 
| IFA | International Fertilizer Industry Association | 
| IPG | Institute of Physical Geography Hydrology Group (Goethe-University Frankfurt) | 
| GDR | UC Berkeley Geospatial Data Repository | 
| USDA | United States Department of Agriculture; http://www.pecad.fas.usda.gov/cropexplorer/ | 
| EEA | European Environment Agency | 
| WRI | Earth trends The Environmental Information Portal | 
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