Distribution of soil minerals along the toposequence of Hyang-Argopuro Volcanic Mountain, Jember, Indonesia

Abstract

The study was conducted in the Hyang-Argopuro volcanic mountain in Jember, Indonesia, with the aim of assessing the distribution of soil minerals along a toposequence and their relationship to soil genesis. Three soil profiles representing the upper, middle, and lower slopes of the toposequence were analyzed. The results revealed that the predominant sand minerals in the soils are opaque minerals, weatherable minerals, amphibole groups, and ferromagnesian minerals. The presence of magnetite, primarily found in the soil profile on the upper slope, suggests the effect of the well-drained topography on its formation. Clay mineral analysis showed that halloysite dominates in soil profile 1, along with traces of gibbsite and cristobalite in the surface horizon. Soil profile 2 is characterized by a combination of halloysite and illite, while kaolinite and illite dominate in soil profile 3. The presence of illite in these soils aligns with previous studies conducted in volcanic regions. The degree of soil development follows the sequence: Soil Profile 2 > Soil Profile 1 > Soil Profile 3. This corresponds to the soil classification, where soil profile 3 is classified as an Alfisol, soil profile 1 as a Mollisol, and soil profile 3 as an Inceptisol. The Andic properties, such as low bulk density and high pH in NaF, observed in soil profile 1 suggest its development from an Andisol. Overall, the study findings highlight the significant influence of basaltic andesite parent material, mountainous topography, and warm and wet climate on the mineral composition and development in the area.