In which country most of the N required for crop production through N₂ fixation by legumes

In New Zealand, most of the N is required for crop production through Nitrogen fixation by legumes.
Fertilizer usage in New Zealand grassland farming is almost entirely confined to the application of non-nitrogenous fertilizers and lime to grass or clover pastures. Once established and effectively nodulated, with satisfactory mineral nutrition clovers can obtain their nitrogen for growth through symbiosis with rhizobial bacteria.