Irrigation Timing and Subsurface Drip Placement Improves Soil Surface Wetting for Tall Fescue Establishment.

Best management practices for turfgrass water use are needed as demands for potable water increase worldwide. Subsurface drip irrigation (SDI) has shown promise to reduce turfgrass water use. The objectives of this project were to: 1) determine drip line placement depth for sand-based turfgrass rootzones, 2) determine irrigation scheduling (pulsing versus continuous irrigation) for uniform surface wetting, and 3) determine best depth and irrigation schedule for establishment of tall fescue from sod and seed. Two experiments were conducted. In Experiment 1, twelve, 3.6 m x 3.6 m independently irrigated plots were constructed in Las Cruces, NM with 40 cm sand rootzones. Each plot was irrigated with one of three subsurface drip depths; 8, 15 or 23 cm or was irrigated with rotary overhead sprinklers (SRS; Hunter Industries Inc.). Subsurface drip lines (Netafim Ltd) were placed on 30 cm intervals with emitters on 30 cm centers along the drip lines. Timings of irrigation were 1 min on/1 min off, 4 min on/4min off or 16 min continuous run times. Amount of water reaching the soil surface was measured by placing a 900 cm2 cloth towel and 11 kg weight on the soil surface. Pulsing provided 48-63% more water to soil surface than continuous irrigation, however only sprinkler irrigated plots successfully established tall fescue. In Experiment 2, sixty bucket lysimeters with SDI placed at 8 cm in a sand based rootzone were used to compare several management practices (Dry vs. moist soil, dry vs. moist sod, and rolling vs. not rolling) to improve establishment of tall fescue sod and seed. Sod quality was evaluated on a 1 to 9 scale during establishment at 2 weeks after sodding. Preliminary trial runs showed moist soil and moist sod improved tall fescue quality at establishment from 2.5 to 8.0.