Chicory productivity, forage quality, and response to nitrogen fertilization

Chicory (Cichorium intybus L.) shows potential for use in grazing systems. Information is needed regarding the productivity and quality of chicory forage in midlatitude states of the USA. Forage yield and quality of chicory under several levels of N fertilization were determined in a Kentucky field experiment. Plots were established during late spring on a silt loam soil (fine-silty, mixed, mesic Typic Paleudult) and received 0, 50, 100, 150, or 200 kg ha(-1) of fertilizer N annually in two equal portions. Treatments were arranged in a randomized complete block design with four replicates. Herbage was harvested four times each year at 5-wk intervals. With N fertilization, chicory produced maximum dry matter yields of 7.8 and 5.6 Mg ha(-1) in 1992 and 1993, respectively. Increasing N level produced linear increases in first-harvest yields and Linear or quadratic increases at the third harvest, during midsummer, but N effects persisted only during the first growth period after application. Chicory forage was high in moisture: greater than or equal to 850 g kg(-1) in first-harvest forage, which often increased with increasing N level. Chicory remained almost completely vegetative, and forage quality was consistently high. Nitrogen concentration averaged 22.9 and 22.3 g kg(-1) in 1992 and 1993, respectively, and was affected by N fertilization primarily at the first harvest. Chicory forage exceeded 640 g kg(-1) in vitro dry matter disappearance and remained below 400 in neutral-detergent fiber concentration throughout the study. Chicory established rapidly and persisted well. Nitrogen-fertilized chicory produced high midseason yields of high-quality forage, suggesting that this species could supplement cool-season grasses. The high rate and extent of N recovery found for chicory warrants further research to determine optimum N fertilization regimes.