Turfgrass establishment from polymer-coated seed under saline irrigation

Abstract

A study was conducted at New Mexico State University in Las Cruces, NM, in 2009 and 2010 to investigate the establishment of five turfgrass species {'Barrister' Kentucky bluegrass [PoapratensisL.], 'Barvado' tall fescue [Festuca arundinacea Schreb.], 'Premier II' perennial ryegrass [Lolium perenne L.], 'Bargusto' bermudagrass [Cynodon dactylon (L.) Pers. × Cynodon. transvalensis Burtt-Davy], and 'Sea Spray' seashore paspalum [Paspalum vaginatum O. Swartz]} from coated and uncoated seed. The grasses were irrigated at 100% reference evapotranspiration (ET0) during fall, winter, and spring and at 120% ET0during summer with either saline [electrical conductivity (EC) = 2. 3 dS·m-1] or potable water (EC = 0. 6 dS·m-1). Generally, seed coating did not affect seedling emergence negatively when irrigated with saline water. During fall, perennial ryegrass exhibited fastest emergence under both saline and potable irrigation andbermudagrasswastheonlygrasstoshowgreateremergencewhenirrigatedwithsaline water. Perennial ryegrass and tall fescue were the fastest to emerge in spring, regardless of seed coating or water quality. Seed coating delayed early establishment (less than 50% coverage) but did not affect days to reach 95% coverage (DAS95). Bermudagrass and seashore paspalum required the most DAS95 when seeded in the fall; however, bermudagrass needed fewest DAS95 when seeded in the spring. All grasses established faster when seeded in spring compared with fall. Fall-seeded perennial ryegrass and kentucky bluegrass required similar DAS95, whereas kentucky bluegrass seeded in spring was slower to reach 95% coverage than perennial ryegrass. Saline water had no effect on establishment when grasses were sown in fall. Surprisingly, grasses established in spring and irrigated with saline water reached 95% coverage 26 days faster than plots irrigated with potable water. Moreover, the growing degree-day model used in this study did not produce similar values for the different air temperatures and irrigation water qualities.