本邦草地における火入れ温度の測定 : (4)ササ型草地の火入れ温度
1972 年 22 巻 1 号 p. 24-33
詳細
1972 年 22 巻 1 号 p. 24-33
The tests of field-burning were carried out in the Sasa type grassland at the foot of Mt. Zao, Miyagi Prefecture. The temperature change during grassland fires at various heights were recorded automatically by means of iron-constantan thermocouples. The aboveground standing crop of Sasa palmata was about 540 g d. wt./m^2,and the total fuel including the dead body and litter attained to 1300-1400 g d. wt./m^2,of which about 50-95 per cent was burnt. The air temperature up to about 20cm height attained the maximum temperature in 30-90 seconds after the ignition, and the temperature change as the result of burning continued for 4-10 minutes. The maximum temperature recorded was about 400-800℃ at the height of 5 to 30 cm above the soil surface. On the other hand, the temperatures above 200℃ were maintained for 1-6 minutes at the height of 5-15 cm. In the plot where Sasa was grown for a long time, the duff layer (mixture of F layer and H layer) is very thick, attaining to even 5 cm. Even in case where the grassland was burnt exceedingly well, almost all of the duff layer remained unburnt and played a role of adiabatic effect. Therefore, the soil surface temperature of the Sasa type grassland was exceedingly lower than the Zoysia type grassland, to say nothing of the Miscanthus type grassland.
