ARS | Publication request: Seedling success from germination to the first summer mortality event: cheatgrass versus three perennial restoration grass species

Submitted to: Society for Range Management Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: August 15, 2012
Publication Date: February 3, 2013
Citation: Harmon, D.N., Clements, C.D. 2013. Seedling success from germination to the first summer mortality event: cheatgrass versus three perennial restoration grass species [abstract]. In: Proceedings of the Society for Range Management, February 3-7, 2013, Oklahoma City, OK. 66:59.

Technical Abstract: Revegetation of Great Basin arid rangelands is an expensive yet largely unsuccessful process. Establishment predominantly falls below requirements for cheatgrass (Bromus tectorum) suppression (~10 plants/m2). Recent seedling demographic research suggests that seedling mortality from drought and lack of germination are not the main cause of failure but inability to emerge after germination. We examined germination, emergence and seedling survival of cheatgrass, squirreltail (Elymus elymoides), bluebunch wheatgrass (Pseudoroegneria spicata) and ‘hycrest’ crested wheatgrass (Agropyron cristatum) seeded (October 2011) in multiple soil types at the Reno ARS research location. Cheatgrass germination occurred by February (temperature low=27F/-3C: high=37F/3C, 12% gravimetric moisture) and perennials by March (Low=33F/1C: high=41F/5C, 10% gravimetric moisture). Maximum emergence occurred by April 18 (temperature low-=40F/4C: high=59F/15C). April germination percent yielded: cheatgrass 27% (range=47-11), bluebunch wheatgrass 23% (range=45-8), ‘hycrest’ wheatgrass 22% (range=30-10), and squirreltail 14% (range=30-6). Emergence resulted in: cheatgrass 17% (37% decrease post germination), bluebunch wheatgrass 17% (26% decrease), ‘hycrest’ 18% (23% decrease) and squirreltail 15% (7% increase). Seedling survival by late May was: cheatgrass 2.3% (87% decrease), bluebunch 1.25% (93% decrease), ‘hycrest’ 2.55% (86% decrease) and squirreltail 2.15% (86% decrease). July success per seeding effort was: cheatgrass 3.3%, “hycrest’ 2.5%, Squirreltail 1.3% and bluebunch 1.1%. We conclude that seedling mortality from drought is the largest contributor to seedling failure (88%) comparable with germination (78%). Emergence contributed 20% failure. We recognize potential effects of drought (Reno precipitation [October-May] normal 5.4” vs. 2011-2012 actual 2.6”). Results however concur with our years of wild land seeding experiences and observation of seedling mortality.