Ideal Irrigation Management for Establishing Cool-Season Grasses.

Information is lacking on the appropriate amount of irrigation needed to establish cool-season grasses from seed. Moreover, several municipalities limit days to water lawns, raising concerns about the success of the establishment. A study was conducted at New Mexico State University, in Las Cruces, during 2012 and 2013 to investigate the effect of 3 irrigation levels [60%; 120% and 180% potential evapotranspiration (ET₀)] and two irrigation schedules [daily (D) and every second day (ODD)] on the establishment of several varieties of Kentucky bluegrass (Poa pratensis L.), perennial ryegrass (Lolium perenne L.), and tall fescue (Festuca arundinacea Shreb.). Plots were seeded on September 25^th 2012, and fertilized monthly with 5g N m^-2. Digital image analysis was used to measure percentage of cover on a bi-weekly interval. Sensors were installed at 5cm depths to record temperature and soil moisture content. A sigmoidal model was used to estimate the days after seeding to reach 50% (DAS50), and 95% coverage (DAS95). Irrigation schedule did not significantly affect establishment, indicating that irrigating every other day had no negative effect. Perennial ryegrass was the fastest grass to reach 50 and 95 % coverage, regardless of the variety. This was followed by tall fescue, then Kentucky bluegrass, which was the slowest to reach both 50 and 95% coverage. Generally tall fescue established (DAS50 and DAS95) equally fast at 120 and180% of ET. Grasses under lowest ET treatment (60%) were the slowest to establish. Kentucky bluegrass established fastest when irrigated at 120% ET followed by 180% and 60% ET. Perennial ryegrass establishment was not affected by irrigation level. Our results indicate that irrigation levels differ in their effect on speed of establishment of cool-season grasses.