Quality‐Based Field Research Indicates Fertilization Reduces Irrigation Requirements of Four Turfgrass Species

The turfgrass industry must respond to increased scrutiny of water use by implementing best management practices that conserve water. Cultural practices, particularly fertilization, may reduce turfgrass water requirements. The fertilization response of two cool‐season species [ Poa pratensis L. and Schedonorus phoenix (Scop.) Holub] and two warm‐season species [ Cynodon dactylon (L.) Pers. and Bouteloua dactyloides (Nutt.) J.T. Columbus] was assessed for turfgrass quality during the 2‐yr experiment at Las Cruces, NM, when treated with 39 kg N ha −1 and subjected to a moisture gradient using linear gradient irrigation systems. Fertilized turfgrass swards maintained acceptable turfgrass quality with lower irrigation rates than swards receiving no fertilization. During Year 1, unfertilized P. pratensis and S. phoenix required 114% evapotranspiration (ET) irrigation replacement to maintain acceptable quality compared with only 70% ET when fertilized. In Year 2, all four turfgrass species required 71% ET irrigation replacement to maintain acceptable quality when not fertilized, compared with only 50% ET when fertilized. In Year 2, P. pratensis required 85%, S. phoenix required 75%, C. dactylon required 55%, and B. dactyloides required 27% ET irrigation replacement to maintain acceptable quality. During Year 2, the amounts of irrigation required to maintain 100% turfgrass cover were 65% potential ET for P. pratensis, 52% for S. phoenix , 31% for C. dactylon , and 11% for B. dactyloides . The proper use of fertilizer can increase turfgrass quality, plant growth, and canopy growth to reduce soil evaporation. The additional growth and transpiration rates expected with nitrogen fertilization do not appear to limit the ability of the turfgrasses to tolerate lower irrigation amounts.