Forest Conversion to Agricultural Lands: Impact on Soil Physical Characteristics Uswah Hasanah (a*), Al Adawiah Amami (a), Rachmat Zainuddin (a), Bunga Elim Somba (a), Rezi Amelia (a)
a) Department of Agrotechnology, Tadulako University
Jl. Soekarno Hatta No.KM. 9, Palu 94148, Indonesia
*uswahmughni[at]yahoo.co.id
Abstract
Forest conversion to other land uses particularly for agricultural purposes had been widespread globally including Indonesia. Removal of the forest cover exposes its organic matter to harsher climatic condition declining soil physical characteristics. This paper discusses changes in several soil physical characteristics when forest was converted into agricultural cultivation i.e. fallow (shrubs), wetland rice, cacao, durian, and avocado land uses. Undisturbed and disturbed soil samples were taken from each land use and analyzed for texture, soil organic carbon (C), soil bulk density, and hydraulic conductivity. All land uses had sandy loam texture except silty loam in wetland rice. The forests had the highest C-organic content (4.70%) whereas the others contained less than halve (<2.01%) of that in the forest land. Bulk density in the forest soil was less than 1.00 g cm-3 while the others ranged between 1.53 g cm-3 to 1.75 g cm-3. The lowest soil permeability was found in the avocado plantation (0.18 cm h-1) and the highest in the forests (9.46 cm h-1), while the others ranged from 2.03-2.47 cm/hour. This study demonstrates that the physical qualities of the soil significantly deteriorated after forests were converted to agricultural lands.
