Page 67 - Ilmu Tanah Book

54 The Chemistry and Fertility of Soils under Tropical Weeds

Chapter 4

Effects of Forest Conversion

4.1 Effects on Weeds and Other Vegetation
4.2 Effects on Soil Enzymatic Activities
4.3 Effects on Soil Chemistry and Fertility
Key Questions

L
and-use conversion may cause tremendous effects on plant cover, soil
biodiversity, and soil properties. Salam (2014; 2017) shows that forest
conversion from primary forest to secondary forest and finally to coffee
plantation and the more intensive uses of cultivated lands caused significant
changes in weed dominances and soil chemistry and fertility. Lampung that was
originally covered by the primary forest has changed to the secondary forest and a
big part of it had in the last five decades been converted to plantations and other
uses such as residential areas and cultivated lands. The composition of West
Lampung area, for example, is shown in Table 4.1, comparing the composition
between the existing land-uses in 1978, 1984, and 1990, only about 12 years
duration from 1978 to 1990. This trend alone tells about the very significant
changes in plant cover, soil biodiversity, and soil chemistry and fertility since every
land-use may show different covers, biodiversity, and soil chemical and fertility
properties.
Clearly shown in Table 4.1 that in 1978 the primary forest covered about
32.60% of the area. Six years later, the coverage decreased to 21.39% in 1984 and
to 12.72% for the following 12 years in 1990 (Salam et al., 1998b). The decreases

Abdul Kadir Salam and Nanik Sriyani – 2019