Study on Spot Heating Technology of Hydroponics Strawberry by Using Low Density Polyethylene Pipe

Abstract

Abstract. The effects of spot heating on growing Strawberry in a nutriculture bed during Winter by spot heating system was estimated at Strawberry plastic greenhouse in the Nonsan Strawberry Experiment Station. The temperature of heating water was controlled by electric water heating boiler and maintained at the range of 21~23℃. Heating pipes were installed in root zone and put that very close to crown spot. Spot heating effect was tested in three cases which were heating root zone, root zone plus crown spot and crown spot only. White low density polyethylene pipe in external diameter of 16mm was installed on crown spot, and Stainless steel flexible pipe in nominal diameter of 15A was installed in root zone. Crown and root zone heating water circulation was continuously performed at a flowrate of 420 L/hr all day long. Strawberry production per bed was surveyed from Dec. 1, 2013 to Mar. 15, 2014. The accumulated yield growth rate compared with a control bed of crown heating was 43% and that of root zone heating bed was 39% and that of Root zone puls crown heating bed was 39%. The temperature of root zone in root heating bed was maintained at 18.0 ~ 23.0 ℃ and that of crown spot was maintained at 12~16℃. Also, Average temperature of crown in crown spot heating bed was raised higher by 3~5℃ and that of root zone in root zone heating bed was raised higher by 5~10℃ than those of control bed