Page 44 - Enzymes in Tropical Soils

32 Enzymes In Tropical Soils

(Dash et al., 1981; Harrison, 1983; Moyo et al., 1989; Sparks, 1989; Neal, 1990),
and/or soil pH (Frankenberger and Johanson, 1982; Malcolm, 1983; Rojo et al.,
1990; Reddy et al., 1991; Sakai and Tadano, 1993; Trasar-Cepeda et al., 1991;
Garcia et al., 1993; Huang et al., 1995; Salam et al., 1998d;1998i). However, the
activities of soil enzymes will decrease above the optimum soil water, soil
temperature, and/or soil pH. The activities of soil enzymes are also reported to
increase with the increase in the populations and activities of soil microorganisms
(Duxbury and Tate III, 1981; Ross and Cairns, 1982; Frankenberger, Jr. and Dick,
1983; Jha et al., 1992; Joner and Jakobsen, 1995; Vinotha et al., 2000).

Important Questions

1. Explain the Nutrient Balance in the soil system! Explain its relationship with Food
Chain!
2. Explain the role of soil enzymes in the Soil – Plant – Animal/Human Relationship!
3. Explain the Nutrient Cycle in the Soil – Plant System! What happens in a closed
system?
4. Explain the Nutrient Cycle in an Open System!
5. Explain the sources of organic matter accumulation in the environment!
6. Does the organic matter accumulation in the environment cause some problems?
Explain!
7. Do the accumulated organic matters in the environment have potentials for some
uses? Explain!
8. Explain the nutrient contents of organic matters or organic wastes!
9. Can the organic wastes in big towns/cities be used for supplying nutrient elements in
the soil system? Explain!
10. What is the role of soil enzymes to solve the problems caused by organic matter
accumulation in the environment? Explain!
11. Mention and explain several factors that may influence the decomposition of organic
matters in the environment!
12. May the presence of enzymes in soils solve the problem of nutrient supplies in
agriculture? Explain!

Abdul Kadir Salam - 2014