The air was provided with a pump (D.K.-200, Daekwang
Elec. Appl. Co., Korea) and sent through a humidifier.
Soil temperature in the column was measured using thermometers
placed in the center of each column at depths
of 37.5 and 87.5 cm below the top of the column. During
the experimental period, the temperature of the room
where the columns were located was maintained at 23 ±
3 C.