Development and use of a variable-speed lateral boom irrigation system to define water requirements of 11 turfgrass genotypes under field conditions

Improved irrigation scheduling is one strategy by which water management can be improved in turfgrass systems. The development and testing of a variable-speed lateral boom irrigation system for use in field-based irrigation trials is reported. Christiansen's coefficient of uniformity was greater than 92% and the efficiency of irrigator discharge was greater than 90% for application depths (mm/unit land area) of 0.5 - 13 mm. The minimum irrigation requirements were determined for 11 turfgrass genotypes from a summer irrigation dose - response field trial that applied daily treatments of 100 ( control), 80, 60, 40 and 20% of the previous day's net evaporation measured using a US Class A pan. Responses of several shoot parameters, including clipping production, green leaf area index, leaf chlorophyll and leaf water status were evaluated to define minimum irrigation requirements for the turfgrasses. Minimum irrigation requirements ( as defined by declines of 10% in several shoot responses) for C-3 and C-4 turfgrasses were 64 - 94% and 32 - 78% of US Class A pan, respectively. Variability in irrigation requirements within C-3 or C-4 types was due mainly to variations in estimates based on the different shoot parameters. The results demonstrate the opportunity for water conservation by using C-4 rather than C-3 turfgrasses in locations with hot dry summers ( and mild winters) typical of a Mediterranean-type climate.