抄録
A new irrigating and soil-warming cultivation system was developed. There was only one porous ceramic pipeline that was used simultaneously as an irrigating pipe and as a warming pipe in this developed system. The cultivation experiment with lettuce verified that this system was practical for irrigating and warming soil simultaneously. Because the irrigating was also from the heating pipe, there was not the problem of the soil drying around the pipe. On the basis of surveying the longitudinal and cross-sectional temperature distributions in the bed soil, the heat sources for heating soil were analyzed under different conditions. The relationship between the soil temperature and the circulating water temperature was also studied in different air temperatures. The required water temperature for warming soil was obeyed to the power function of the air temperature in this ceramic pipe system. When the lowest air temperature at night was not less than 6.6°C, 30.0°Cwater was enough if the soil was warmed only to 15°C. The growth and yields of lettuce in the warming treatment were significantly better than those in the no-warming treatment.
