Gilgai microtopography of soil from carbonate rocks
Asmita Ahmad- Christianto Lopulisa

Universitas Hasanuddin

Abstract

Gilgai microtopography is a characteristic topography of soils that develop from carbonate rocks which are influenced by the presence of smectite clay minerals. The process of forming a gilgai can inhibit the development of plant growth and soil stability. Soil genesis is an interesting topic to study, especially concerning how the process of moving clay forming a gilgai microtopography. The objective was to study the process of forming a gilgai microtopography which is formed from the parent material of carbonate rock in Mangarabombang District, Takalar Regency. The methods used are survey methods, analysis of soil physical characteristics and soil chemistry, and soil mineral. The results showed an increase in clayeyness at the top horizon in line with decreasing permeability on the top horizon and inversely proportional to soil porosity. The cation exchange capacity is higher at the top horizon, which indicates an increase in clay content. The mineral content of clay is nontronite as a member of the smectite group. Nontronite mineral formation subsidized by calcium and magnesium cations from carbonate rocks. This mineral absorbs more water and caused the saturation conditions that triggering lateral pressure and formed a gilgai micro-topography.

Keywords: gilgai, permeability, porosity, smectite

Topic: Crop Production and Environment