Page 70 - Enzymes in Tropical Soils

58 Enzymes In Tropical Soils

Bergstrom and Monreal, 1998). Some researchers found that the activities of
alkaline and acid phosphatases were higher in the root zones and decrease to the
directions of the bulk soils uninhabited by plant roots (Joner and Jakobsen, 1995).
Salam et al. (1997a) also found that the activities of phosphatases in soil differed
depending on the vegetation. The activity of acid and alkaline phosphatases were
reported to be higher in the root-zones of alang-alang (Imperata cylindrica) than
those in the root-zones of green kyllinga (Cyperus kyllingia), pigweed (Amaranthus
spinosus), and amaranth (Amaranthus tricolor), while those in the root-zone of
pigweed was the lowest (Table 4.1). Jha et al. (1992) also showed that the soil
phosphatase was higher in undisturbed forests than those in soils that had
encountered deforestation.

Table 4.1. The activities of phosphatases in the root zones of
several tropical weeds.

Weed Acid Alkaline
Phosphatase Phosphatase
-1
mg p-Nitrophenol g h
-1
Alang-alang 178 63
Green Kyllinga 152 41
Pigweed 110 34
Amaranth 170 43
Adapted from Salam et al. (1997a)

Important Questions

1. What is the role of soil enzyme in relation to the nutrient cycles in the soil – plant
systems?
2. What is the benefit of soil enzymes related to the status of soil fertility in a close and
in an open soil system? Explain!
3. What is the benefit of soil enzymes in managing organic waste in the soil system?
Explain!
4. How is the understanding on the soil enzymes as related to the soil environmental
factors useful for managing organic matters as nutrient sources? Explain!
5. Explain the producers of soil enzymes!
6. How do the soil microorganisms affect the soil enzymatic activities?
7. How do the soil macroorganisms affect the soil enzymatic activities?

Abdul Kadir Salam - 2014