Deficit Irrigation Programs for Water Conservation in the Management of Bermudagrass Fairways in Texas.

In recent years, water availability for golf course irrigation use has been heavily scrutinized due to persistent drought conditions, diminishing potable water supplies, and increasing population growth.  Information is limited regarding minimal levels of reference evapotranspiration (ET_o)- based irrigation needed to maintain adequate summer fairway performance and fall recovery in the south-central U.S. This 2-year study evaluated 1) the response of ‘Tifway’ bermudagrass (Cynodon dactylon x C. traansvalensis Burt. Davy) fairway plots to irrigation levels of 0.6, 0.45, 0.3, and 0.0 x ET_o, with and without simulated summer traffic and 2) the effects of prior irrigation level and traffic on fall recovery at full irrigation levels. In the absence of traffic, irrigation at 0.3 x ET_o or sustained acceptable quality in both years, while withholding irrigation altogether resulted in unacceptable turf quality. Summer traffic stress reduced quality and percent green cover across all irrigation levels.  Upon resuing full (0.6 x ET_o) irrigation levels in autumn, deficit and unirrigated treatments each rebounded to 80-90% green cover by late fall if year 1.  However, in year 2, only irrigated plots recovered to acceptable levels, with unirrigated plots suffering substantial injury and attaining only 30% green cover by late fall. Effects on divot recovery time and root development due to irrigation treatments were also noted. Overall, data suggest that provision of minimal levels of deficit irrigation during summer drought may be critical to sustaining turf viability and promoting rapid fall recovery of bermudagrass following successive years of summer drought stress.