"Someday men will learn to irrigate and apply fertilizer instead of praying for fertility" Warren Eyster. Nitrogen (N) and water (W) management practices are key components in irrigated crop production. Plants cannot grow in soil without water, so too when soil is saturated with water. Plants lacking N show stunted growth and yellowish leaves. Too much N can have negative environmental impacts such as water contamination and eutrophication. Leaching is the main vehicle through which applied N can contaminate groundwater. Understanding of N movement through soil profile is also essential for more N efficient and minimizing N leaching. This book provide the findings of the study in which maize agronomic response were evaluated against different water and N application regimes; lateral and vertical movement of nitrogen under different irrigation regimes were determined; and distribution pattern of nitrogen in the maize root zone was modeled. The book provides management practices for optimizing economic application regimes for N and W to maximize irrigated maize production.