Seedbed effects on grass establishment on abandoned Nebraska Sandhills cropland

Abstract

Perennial grass establishment on abandoned cropland in the Nebraska Sandhills is difficult due to low soil fertility, organic matter, and water holding capacity and high potential erodibility. Establishment is further complicated by unpredictable precipitation and weed competition. Two warm-season grasses: sand bluestem [Andropogon gerardii var. paucipilus (Nash) Fern.] and switchgrass (Panicum virgatum L.); and 2 cool-season grasses: smooth brome (Bromus inermis Leyss.) and intermediate wheatgrass [Thinopyrum intermedium (Host) Barkw. & D.R. Dewey subsp. intermedium] were evaluated with spring-seeded field trials. Seedbed preparation [untilled, disced, and dead oat (Avena sativa L.) cover (DOC)] effect on seeded grass and nonseeded species densities was evaluated in 1985 and 1986 at 2 locations on Valentine sands (Aquic Ustipsamment). In 1985 1 site was irrigated. Both sites were dryland in 1986. Stand failure (< 5 seedlings/m2) occurred on the dryland site in 1985 due to low, erratic precipitation. Stands evaluated in June 1986 on plots established with irrigation in 1985 had 38, 46, and 61 plants/m2 for the untilled, disced, and DOC seedbeds, respectively. The disced or DOC seedbeds were required for successful (>10 plants/m2) dryland seedings in 1986 at both locations. Irrigation the establishment year minimized risk of stand failure and allowed the use of any seedbed preparation or grass species studied. Sand bluestem was the only species to establish both years. However, if a dryland seeding of a cool-season species is desired, intermediate wheatgrass appeared more adapted than smooth brome.