Page 85 - Ilmu Tanah

72 The Chemistry and Fertility of Soils under Tropical Weeds

9. Explain the lifetime of soil enzymes in relation to proteases existing in the soil
environment?
10. Does deforestation affect soil enzymes? Explain!
11. Explain the magnitude of the soil enzymatic activities in different land-use system like
primary forest, secondary forest, monoculture plantation, and cultivated land!
12. Explain the difference of soil enzymatic activities in wood land versus meadow and
cornfield!
13. Explain the relationship between the functions of plant roots and the soil enzyme
production!
14. Explain the effect of fire on enzymatic activities!
15. Explain the effect of soil water content on the soil enzymatic activities! Does it relate to
the existence of the enzyme producers?
16. How is the relationship between the soil total N and the organic C content with the soil
enzymatic activities? Explain why!
17. Explain the effect of the existence of weeds in coffee pantation on the soil enzymatic
activities!
18. How does the forest converstion affect the optimum pH of phosphatase? What is
optimum pH?
19. How is the effect of Cu on the optimum pH of phosphatase?
20. How does the soil pH affect the soil enzymatic activities? Explain the chemical reasons
behind this phenomenon!
21. How does the soil pH affect the soil phosphatase activities? Explain the chemical
reasons behind this phenomenon!
22. What is the effect of CaCO 3 on urease activities! Why?
23. What chemical properties are affected by land-use conversion? Why?
24. How does the land conversion affect the soil micronutrient metals in the soil
environment?
25. Explain the relationship between the soil organic C and total N with the soil CEC and
exchangeable K!

Abdul Kadir Salam and Nanik Sriyani – 2019