Scalping Effect On Spring Green-up of Bermudagrass and Seashore Paspalum.

The use of warm season grasses in transition zones has been limited by their long dormancy period from late fall to spring during which the plants lose their color.  A study was conducted at New Mexico State University on the National Turfgrass Evaluation Programs’s bermudagrass and seashore paspalum trials to investigate if late winter scalping could speed up spring green-up. Grasses were established in 2007 and included 31 bermudagrass and 12 seashore paspalum varieties. Plots were irrigated with saline water (TDS = 1600 ppm) at 100% Reference Evapotranspiration and mowed weekly at 2.5 cm.  The study design was a completely randomized block with scalping applied as a strip-plot treatment. Plots were scalped to a height of 1.5 cm in mid February 2010 using a reel mower, while control plots were left unscalped. Soil temperature was measured at a depth of 2.5 cm using wireless soil sensors.  Percentage green cover of plots was determined from March to June, 2010 in 14 day intervals using Digital Image Analysis. Scalping did not affect daily average soil temperature or daily maximum soil temperature. Non-linear regression was used to calculate Day of Year (DOY) at which grasses reached 50%, 75%, and 90% green coverage. Models predicted green coverage well with coefficients of determination ranging from 0.8 to 0.99. Analysis of variance to compare interpolated DOY values revealed that scalped bermudagrass was faster to reach 50%, 75%, and 90% green coverage by 4, 9, and 15 days respectively, when compared to unscalped plots. Scalped seashore paspalum exhibited 50% and 75% green coverage 15 and 20 days sooner than unscalped plots. Seashore paspalum plots were slow to green-up and did not reach 90% green coverage by June 2010. Results indicate that both bermudagrass and seashore paspalum benefited from scalping and greened up 2 and 3 weeks sooner than unscalped grasses.