Page 120 - Enzymes in Tropical Soils

108 Enzymes In Tropical Soils

Salam et al., 1998d; 1998i; Sarapatka et al., 2004). Sarapatka et al. (2004) reported
that acid phosphatase activity in the root zones of various species and cereal
cultivars was negatively correlated with increasing pH and available phosphorus
level in the nutrient medium. Frankenberger and Johanson (1982) also reported
the depencence of other enzymes i.e. urease and phosphodiesterase activities on
soil pH. As a result of ionization and deionization of the functional sites of the
enzyme proteins with the increase in soil pH, the activities of soil enzymes may
change accordingly.
As mentioned previously, this behavior was clearly demonstrated by
phosphatase in tropical soils. Salam et al. (1998d) treated tropical soil samples of
some deforested locations in West Lampung, Indonesia, at a series of buffered pH
of 3 to 12. The results are shown in Fig. 7.2. A similar patterns were also reported
by Trasar-Cepeda et al. (1991) and Nakas et al. (1987). Ekenler and Tabatabai
(2003) suggested that acid phosphatase was the most sensitive and arylsulfatase
the least sensitive to changes in soil pH.

500

Act. of Phosphatase (mg p-Nitrofenol g -1 h -1 ) 300 Primary Forest
400

Secondary Forest
200
Coffee Plantation
100

0 Cultivated Land
3 4 5 6 7 8 9 101112
pH

Fig. 7.2. The relationship between phosphatase activity and pH in soils of different land-
uses from West Lampung Indonesia (Adapted from Salam et al., 1998d).

Abdul Kadir Salam - 2014