Productivity, botanical composition, and nutritive value of swards including forage chicory

Pure stands of 'Grasslands Puna' chicory (Cichorium intybus L.) are product ive and responsive to N fertilization in the eastern USA. We conducted a fi eld experiment for 3 yr to investigate productivity and nutritive value of swards including chicory, orchardgrass (Dactylis glomerata L.), and birdsfo ot trefoil (Lotus corniculatus L,) as a function of clipping frequency (3- and 6-wk intervals). Each treatment was replicated three times on an upland site of Dekalb series soil (loamy-skeletal, mixed, subactive, mesic Typic Dystrochrept). Modest rates of N, P, and K were applied annually. Herbage m ass, botanical composition, in vitro organic matter disappearance (IVOMD), and crude protein (CP) were determined. Cumulative herbage yield was not in fluenced by initial sward composition with chicory, chicory-orchardgrass, a nd chicory-orchardgrass-trefoil averaging 6.8 Mg ha(-1) during a growing se ason. Clipping frequency influenced yield with canopies clipped at 6-wk int ervals producing 26% more herbage than those clipped at 3-wk intervals. Gro wth rates of canopies clipped at 6-wk intervals averaged 51 kg ha(-1) d(-1) early in the growing season, suggesting that swards including chicory woul d be responsive to nutrient inputs and where rapid herbage regrowth and nut rient use by the growing crop are needed. Chicory declined in swards with t ime, regardless of initial sward composition or clipping frequency, Fluctua tions in IVOMD and CP were related to changes in sward composition arising from the interaction of time and clipping frequency, Including orchardgrass and trefoil retarded invasion of less desirable species and so provided a means to control overall sward productivity and herbage composition.