Coating Warm-Season Turfgrass Seed to Improve Establishment Under Saline Conditions.

Saline irrigation has been proposed as a water conservation strategy to irrigate turfgrass areas, however, salinity can hinder the germination process and be detrimental for turfgrass seedling establishment. A study was conducted during the summer of 2014 at the UC Riverside turfgrass research facility in Riverside, CA, to determine: 1) effects of five experimental seed coatings and Zeba coating on the establishment of ‘Princess 77’ bermudagrass and ‘Sea Spray’ seashore paspalum when irrigated with increasing levels of saline water; and 2) how irrigation salinity affects seedling establishment of ‘NuMex Sahara’ bermudagrass, ‘Whittet’ kikuyugrass, and ‘Sundancer’ buffalograss. A line-source experiment was designed to alternate distribution of potable and saline water to establish an irrigation salinity gradient, identifying 5 different electrical conductivity (EC) levels (2, 3, 4.5, 5.5, and 7 dS/m). Percent ground cover was assessed weekly throughout the experiment using Digital Image Analysis. By the end of the experiment (three months after seeding), the only seed coating treatment that had a positive effect on bermudagrass establishment was ASET 4000 6%, which increased turf cover in comparison to uncoated seed at 3 and 7 dS/m. In particular, ASET 4000 6% coating on Princess 77 achieved the highest overall turf cover (63%) when irrigated with saline water at 7 dS/m. Seashore paspalum coated with ASET 4000 1% reached the highest overall cover (97%) when irrigated at 2 dS/m, and showed higher turf cover in comparison to the uncoated treatment (76% vs. 67%) when irrigated at 5.5 dS/m. Kikuyugrass was slower to establish under saline conditions compared to bermudagrass and seashore paspalum, reaching only 79% cover at 2 dS/m and 0% at 7 dS/m. Of all turfgrass species evaluated, buffalograss seedling establishment was slowest and most impacted by irrigation salinity.