Page 172 - Enzymes in Tropical Soils

160 Enzymes In Tropical Soils

Forest fires was also reported to affect the soil enzymatic activity. Saa et al.
(1993) reported that wildfires strongly lowered the activity of acid phosphatase and
caused an intense mineralizing effect on organic P, and hence profoundly increased
the inorganic P fractions. However, the controlled fire did not affect acid
phosphatase and only slightly affected the organic P mineralization and the soil
inorganic P fractions. Wildfires were also reported to greatly affect the soil organic
C and total N. Abelle and Engel (2013) noted that burned areas had significantly
greater soil C and total N than did unburned areas across communities on the
landscape of Mojave Desert.
The forest conversion was also observed to affect the shifting in the
optimum pH for phosphatases. As shown previously (Fig. 7.2), land-use conversion
from the primary forest to the secondary forest, coffee plantation, and cultivated
lands shifted the optimum values for phosphatases to higher values (Fig. 10.1). The
value of the optimum pH in the primary forest was the lowest i.e 5.0 and that in
the coffee plantation was the highest i.e 6.3 (Salam et al., 1998d).

7
6.5
6
5.5
5
4.5
4
3.5
3

Fig. 10.1. The shifting of optimum pH by forest clearing and
land-use conversion (Salam et al., 1998d).

Abdul Kadir Salam - 2014