Influence of nitrogen on productivity and nutritive value of forage chicory

Chicory (Cichorium intybus L.) is highly productive and responsive to N fertilization under midsummer conditions in the eastern USA. We conducted a field experiment for 3 yr on a Ramsey soil (loamy, siliceous, subactive, mesic Lithic Dystrudept) in southern West Virginia to determine if fertilizer N influenced forage chicory nutritive value and NO3-N concentration. Each N rate (0, 80, 160, 240, or 480 kg N ha(-1)) was replicated three times in a randomized block design. Swards were clipped at 6-wk intervals during the growing season. Swards were virtually pure chicory in the first year (1994) regardless of N rate. By the third year (1996), chicory ranged from about 40% (0 N) to less than 5% (480 kg N ha(-1)) of swards. Botanical composition changes in the sward influenced dry matter (DM) response to N rate and herbage nutritive value. Dry matter production increased with N rate in 1994, but was not affected by N in 1996 when chicory was not a major sward component. More than 70% of total annual DM production in 1994 occurred after the first harvest, but by 1996 was less than 50%, reflecting productivity patterns typical of cool-season swards. Nitrate concentrations in herbage were greatest (3.5 g kg(-1)) in 1995, a relatively dry year, and least (2.3 g kg(-1)) in 1996, when there was less chicory in the sward. Crude protein (CP) and in vitro organic matter disappearance (IVOMD) values indicated high forage quality throughout the course of the experiment.