Page 102 - Enzymes in Tropical Soils

90 Enzymes In Tropical Soils

in Fig. 6.5. As seen in Fig. 6.5, at day time, the topsoil temperature is higher than
that of subsoil . Conversely, at night time, the topsoil temperature is lower than
that of subsoil.

50
Soil Temperature ( oC) 30 Day-Time
40

20

Night-Time
10
0
0 5 1015202530
Soil Depth (cm)

Fig. 6.5. Hypothetical fluctuation of soil temperature with soil
depth (Salam, 2012).

The soil temperature is also related to the air temperature and, in general,
soil temperature is always higher than air temperature. This relationship shows
that the soil temperature may be predicted by the air temperature data for a
particular area. Because the soil temperature is usually higher than the air
temperature, the soil temperature may be predicted by the air temperature plus a
particular constant. This constant may be devised by studying the empirical data
for a particular area and range of time. One of the relationship is that developed in
Terbanggi Besar, Central Lampung, Indonesia (Wiharso, 1998). This relationnship is
shown in Eq. 6.1 and Eq. 6.2 as follow.

o
T s = T a + 1.9 ( C) ....... Eq. 6.1 (Dry Season)
o
T s = T a + 2.2 ( C) ....... Eq. 6.2 (Rainy Season)

where T s is soil temperature and T a is air temperature. These equations clearly
show that the soil temperature in the Rainy Season is Higher than that in the Dry
Season.

Abdul Kadir Salam - 2014