Effects of St. Augustinegrass genotype and irrigation frequency on turfgrass quality in a subtropical environment

Growing urban populations have placed greater demands on municipal water supplies, especially during dry periods. Efforts are underway to develop turfgrasses with better performance using less irrigation. The objective of this research was to assess the effects of irrigation management and St. Augustinegrass [Stenotaphrum secundatum (Walter) Kuntze] genotype on turf quality (TQ). The field study conducted in Citra, FL, was a split-plot design with the main plot (irrigation) arranged in blocks. Calendar-based irrigation treatments were soil sensor-based, 8X, 4X, 2X, and 1X per month (MO) and none. St. Augustinegrass genotypes included three commercial cultivars and eight experimental entries. Turfgrass quality varied with time, genotype, and irrigation. Sensor-based and 8XMO irrigation produced the highest TQ values, ranging from 5 to 7 for all cultivars, but sensor-based irrigation used less water overall. Turf quality declined with 2XMO and more restrictive irrigation frequencies, with TQ values ranging from 2 to 4. Several recently developed breeding lines performed better across all the irrigation treatments than current commercial cultivars. To satisfy both municipal watering restrictions and turfgrass health requirements, sensor-based irrigation coupled with the use of improved breeding lines and cultivars such as DALSA 1618 or FSA1602 (CitraBlue^®) offer the potential to maintain quality turfgrass while substantially reducing residential irrigation use.