Perennial Grassland Establishment and Production Response Following Different Annual Cropping Systems.

Developing efficient, economical methods of perennial mixture establishment in a semi-arid environment is needed for grazing and conservation purposes.  We evaluated different perennial monocultures and mixtures planted into various annual crops (spring wheat, corn, soybean, dry pea, and canola) to determine establishment and subsequent production variation near Mandan, ND.  Experimental design was a randomized complete block with a split-split plot treatment structure with 4 replications established in 2010 and 2 additional replications established in 2011.  Perennial monocultures consisted of switchgrass and intermediate wheatgrass and binary mixtures of intermediate wheatgrass + alfalfa and switchgrass + alfalfa.  High-input moderate diversity treatments included warm-season mixtures (switchgrass, big bluestem, indiangrass, and little bluestem) and cool-season mixtures (western wheatgrass, green needlegrass, Canada wildrye, and intermediate wheatgrass).  Low-input high diversity plots consisted of big bluestem, little bluestem, indiangrass, switchgrass, western wheatgrass, Canada wildrye, prairie junegrass, and green needlegrass, stiff sunflower, goldenrod, narrow leaf coneflower, common yarrow, roundhead lespedeza , purple prairie clover, Illinois bundleflower, and leadplant.  Seeding rate was 450 pure live seed m² for each split-plot treatment.  Perennial mixture treatments were managed according to best management practices. Overall, perennial stand establishment measured using a frequency grid indicated stands were fully successful (>40%) with perennials established into soybean residue having the highest stand frequency.  End of season biomass yields, following the establishment year, were highest for intermediate wheatgrass (8.2 Mg ha^-1).