Conversion Systems of Bermudagrass to Switchgrass or Mixed Nativegrass.

In the southern Great Plains, research has demonstrated that switchgrass (Panicum virgatum) has excellent forage potential. Switchgrass begins spring growth earlier than many introduced warm season perennial grasses, i.e. bermudagrass (Cynodon dactylon). This enables it to provide abundant, high quality forage with good stocker cattle gains from early to late spring. Nativegrass mixtures can also provide early season forage and contain grasses that vary in seasonal forage distribution providing higher quality forage further into the growing season than switchgrass.  Compared to bermudagrass, switchgrass or nativegrass mixtures increase wildlife habitat, lower maintenance cost, and can improve land value. These benefits have increased interest in conversion of bermudagrass land areas to switchgrass or nativegrass. Because of its herbicide tolerance, ability to propagate from stolons, rhizomes, and seed, bermudagrass is difficult to control making conversion challenging. To be successful, conversion methods need to be acquired.  A two-year, two location conversion study was developed to determine  efficacy of twelve conversion systems for bermudagrass control and establishment of switchgrass (‘Alamo’) or a nativegrass mixture of little bluestem (Schizachyrium acoparium ‘Cimarron’), big bluestem (Andropogon gerardii ‘Kaw’), indiangrass (Sorghastrum nutans ‘common’), switchgrass (‘Alamo’), and green sprangletop (Leptochloa dubia ‘common’).  Conversion systems consisted of combinations of preparation time (7, 11, 19 months from treatment initiation to planting), cover crops (0, 1, 2, 3), glyphosate application (13.8, 18.4, 23 L ha^-1) and tillage (till, no-till). Switchgrass and nativegrass planting date for all conversion systems was April. Tillage systems were more effective than no-tillage. Mean yields across locations and years for no-till were 963 kg ha^-1 and 3219 kg ha^-1 compared to tillage yields of 2517 kg ha^-1 and 7449 kg ha^-1 for nativegrass and switchgrass respectively. Tillage systems with cover crops (2 or 3) and preparation time (11 or 19 months) were more successful in establishing nativegrass and switchgrass than other tillage systems.