GROWTH-RESPONSES OF WARM-SEASON TALLGRASSES TO DORMANT-SEASON MANAGEMENT

A study on Conservation Reserve Program (CRP) land was established in southeastern Nebraska to determine the effect of dormant-season manage ment on subsequent-year growth rates and yields of tallgrasses, The pu rpose of the management practices was removal of standing dead materia l and litter that negatively impact plant growth and grazing efficienc y. Treatments consisted of a control with no residue manipulation and 5 residue manipulation practices including (1) October shredding and l eaving residue; (2) October haying; (3) October intensive grazing; (4) March intensive grazing; and (5) spring prescribed burning, The study was conducted in 1994/95 and 1995/96 on a switchgrass (Panicum virgat um L,) monoculture and mixed stand of warm-season tallgrasses dominate d by big bluestem (Andropogon gerardii Vitman) and little bluestem [Sc hizachyrium scoparium (Michx,) Nash], The manipulation treatments effe ctively removed standing dead material without reducing yields in the growing season following application. Marked switchgrass tillers on th e control plots increased (P < 0.1) in height at a more rapid rate tha n switchgrass on other treatments until late summer in both years, Rat e of morphological development was similar (P > 0.1) for all treatment s in 1995 and 1996, Rate of height increase and morphological developm ent in big and little bluestem on the mixed grass site generally was c omparable or slower on the manipulation treatments than the control in both years; however, big and little bluestem tillers grew relatively rapidly at the end of the 1995 growing season, Because the manipulatio n treatments generally did not increase tiller growth rates of the dom inant grass species, potential harvest dates would be similar to those of untreated areas.