Forcing Culture of Witloof Chicory (Cichorium intybus L.) Using Fermentation Heat of Cow Manure

This research investigated the feasibility of witloof chicory production with fermentation heat of cow’s manure, in Hokkaido, during semi-cold and cold seasons. Forcing culture experiments were conducted in semi-cold season (once, April to May, 2013) and cold season (twice, March, 2014; March, 2015). In each experiment, cow compost produced through solid-liquid separator (water content; 72.6%) was used as heat sources. Temperature of outside air, indoor air, compost container, forcing chambers (soil and air) and heat exchangers were recorded. Through all experiments, compost temperature was maintained up to 30°C, and it showed potential to be used as a heat source for chicory forcing culture. In semi-cold season, temperatures of forcing chambers (6.3 (cid:4) 0.9 (cid:4) 0.65 m) were maintained stably, and average air temperature of forcing chamber reached 17.2°C in average, and marketable etiolated heads (Chicon) were obtained after 22 d. In cold season, air temperature of forcing chamber (3.0 (cid:4) 0.9 (cid:4) 0.65 m) was maintained stably (10.6°C in 2014, 14.4°C in 2015, in average), and marketable heads were obtained after 15 to 19 d. The results indicated that witloof chicory forcing culture in semi-cold and cold seasons by using cow manure fermentation heat as heat sources is indeed possible.