Page 84 - Ilmu Tanah Book

The Chemistry and Fertility of Soils under Tropical Weeds 71

Table 4.9. The changes in some soil properties by land-use conversion
in Tulung Boho Central Lampung*.

Organic C CEC Exch. K
Land-Use pH -1 -1 -1
(g kg ) (cmolc kg ) (mg kg )
Secondary Forest 4.8 24.9 25.9 62.4

Swamp 3.9 19.4 7.7 74.1

Pineapple 4.0 11.8 4.7 3.9

“Sengon” 4.4 16.7 2.7 31.2

Mixed Garden 4.0 10.4 3.1 42.9
Cassava 4.1 13.2 4.7 62.4

Corn 4.7 9.7 1.7 23.4

*Adapted from Salam et al. (1999a)

Key Questions

1. Explain the magnitude of land-use conversion in West Lampung in the period of 1978 -
1984 – 1990? What happen to the primary forest, secondary forest, monoculture
plantation, residential areas, etc.? What is your prediction now and in the near future?
Explain!
2. What are the effect of land-use conversion on plant covers, weed dominance, and soil
chemistry and fertility? Explain!
3. What are the effects of land-use conversion on the soil enzymatic activities? Explain!
4. What was the vegetation dominating the primary forest and the secondary forest?
Explain!
5. Explain the effects of long-term land cultivation with cassava on the soil chemistry and
fertility!
6. Explain the effects of narural vegetation and Paspalum conjugatum on the soil
enzymatic activities in coffee plantation of West Lampung!
7. Why do the living things such as microorganisms, macroorganisms, and plant roots
produce enzymes? What enzymes are produced by these living things?
8. What is the function of soil enzymes? Explain their roles in nutrient cycles!
Abdul Kadir Salam and Nanik Sriyani – 2019