Nitrogen limits productivity in most ecosystems, including agroecosystems.
To overcome this limitation, N fertilizers, both organic and synthetic, are used to increase crop yields. Industrial N fixation for fertilizer has altered global biogeochemical cycling of N, and because N is easily lost from ecosystems , overapplication of N fertilizer pollutes groundwater , saturates downstream aquatic and terrestrial ecosystems with N and causes emissions of reactive N gases to the atmosphere. To eliminate overdependence on this potentially costly input , methods must be developed to sustain high yields without overloading agroecosystems with nitrogen. N limits primary productivity. N is easily lost from ecosystems.