Turfgrass irrigation for soils with high clay contents poses unique challenges due to very slow water infiltration and percolation. The objective of this research was to study the interaction between irrigation inputs and N fertilizer and also to identify minimal levels of soil profile moisture needed to maintain healthy turf grass. The study was conducted on a 0.89 ha linear gradient irrigation system (LGIS) at the Texas A&M University Research and Extension Center in Dallas. The LGIS delivered water quantities ranging from 0 to 120% Class A pan evaporation (Ep) from late spring to early fall when warm-season grasses were actively growing. A wilt line visually separated water stressed from healthy turf. Ammonium sulfate fertilizer, labeled with 15N, was applied to microplots located within the LGIS at irrigation levels that replaced 120, 50, and 0% Ep. Access tubes were installed near each microplot and soil moisture was monitored to a depth of 100cm at 10cm intervals throughout the year. In both 2004 and 2005, the amount of 15N remaining in the upper 15cm of the soil profile was greatest for the 50% Ep and least for the 0% Ep irrigation levels. Turf grass remained visually healthy at the 50% Ep irrigation level, yet there was 10cm less water in the upper 100cm of this soil profile compared to the 120% Ep irrigated soil profile. Significant savings in water and fertilizer use are possible by irrigating at 50 to 70% of Ep versus more liberal applications of water.