Spatial and temporal distribution of salts on fairways and greens irrigated with reuse water.

A 4-yr study was conducted to assess the impact of reuse water on soil salinization of nine golf courses in southern Nevada: three long-term reuse courses, three fresh-water courses, and three courses that transitioned to reuse water during the experimental period. Four of nine fairways had positive leaching fractions (LFs) during all 4 yr, with statistical separation occurring based on 4-yr averages (p < 0.001). Soil salinity levels followed a sinusoidal seasonal curve, with 70% of all peaks associated with summer months. Salinity contour maps (surface soil) were compared over time. More than 85% of the surface area of greens were mapped as electrical conductivity of saturation extract (EC e ) < 4.0 dS m -1 , whereas 64% of the fairways were mapped at EC e < 4.0 dS m This salinity relationship dropped to 13% on fairways of long-term reuse courses. Changes in the average EC e values after transition to reuse water were primarily driven by the number of days a course had been irrigated with reuse water (R 2 = 0.69***). Depth-averaged salinity (sensors) was found to be highly correlated with LF on reuse courses (R 2 = 0.86***) and transitional courses (R 2 = 0.87***). Yearly changes in depth-averaged sensor values on transitional courses were described by an equation that included the number of days a golf course was irrigated with reuse water, the LF, and the uniformity of the irrigation system (R 2 = 0.83***). Although deficit irrigating can be practiced for short periods, adequate LFs are essential for the long-term success of golf courses irrigated with reuse water.