Effect of Irigation Efficiencies on Nitrogen Leaching Losses

The literature was reviewed to determine the effect increasing irrigation efficiencies have had on ${\mathrm{NO}}_3-N$ leaching. The mass of ${\mathrm{NO}}_3-N$ leached is directly related to the drainage volume. By increasing irrigation efficiencies, both the drainage volume and amount of ${\mathrm{NO}}_3-N$ leaching are reduced. Both water management and nitrogen management are important in controlling ${\mathrm{NO}}_3-N$ leaching. By using improved water management practices that control the amount of water applied and using the proper time to apply water, the irrigation efficiency is increased and ${\mathrm{NO}}_3-N$ leaching is reduced. Applying only enough N fertilizer to meet crop requirements for a realistic yield goal, time of application and use of slow release fertilizers are N management practices that will reduce ${\mathrm{NO}}_3-N$ leaching. However, it is impossible to reduce ${\mathrm{NO}}_3-N$ leaching to zero in the humid region on coarse‐textured soils and still maintain adequate crop yields. Nitrogen simulation models cannot be widely used to evaluate N management practices and irrigation water management practices that increase irrigation efficiencies because of the lack of required input data.