Evaluation of grass establishment, development and survival under sod-seeding conditions in the dry subhumid prairies
Gobin, Suzanne M.
In order to increase the nesting potential of pastures and rangelands, increases in the proportion of high quality dense nesting cover (DNC) grasses in the sward are required. Sod-seeding is a system where seeds are placed into an undisturbed pasture or rangeland sod, and this system may be an effective way to establish DNC grasses, especially on fragile soils where pre-seeding tillage is not desirable. Different management practises will affect the degree of success achieved with sod-seeded grass stands. It is not known at the present time if all candidate DNC grass species response similarly to sod-seeding. The objectives of this study were 1) to evaluate different sod-suppression techniques for the establishment of tall wheatgrass [Thinopyrum ponticum (Podp.) Barkw. & D.R. Dewey] under two types of resident vegetation and 2) to compare the relative response of switchgrass (Panicum virgatum L.), green needlegrass (Stipa viridula Trin.), tall wheatgrass, and northern wheatgrass (Elymus lanceolatus (Scribner & J.G. Smith) Gould] to seedbed preparation techniques. Field studies were conducted in 1991 and 1992 at Portage La Prairie and Gladstone, MB and a controlled environment study was conducted in 1992. Grass seedling emergence, development and survival were monitored throughout the growing season, and in some cases, the following season as well. Environmental measurements and competition from the resident vegetation were measured. Results of the first experiment indicated that under conditions of intense competition from rhizomatous resident vegetation, such as with bromegrass (Bromus inermis L.) and Poa species at Gladstone, chemical suppression of the resident vegetation was critical for successful establishment, development and survival of tall wheatgrass plants... Results of the second experiment indicated that suppression of the resident vegetation increased plant density, development and survival of all four sod-seeded grasses over the untreated control. The tall and northern wheatgrasses were the most conducive to sod-seeding, and the switchgrass and green needlegrass the most difficult grasses to establish successfully.