MICROMORPHOLOGICAL CHARACTERISTICS OF (POTENTIAL) ACID SULPHATE SOILS UNDER THE BANJERESE TRADITIONAL LAND MANAGEMENT (BTLM) SYSTEM

Budi Mulyanto, Basuki Sumawinata, Gunawan Djajakirana, and Suwardi (2000)

ABSTRACT

The relationship of micromorphological characteristic of (potential) acid sulphate soils and under the Banjarese traditional land management (BTLM) system have been studied in Karya Tani Village, Barambai, South Kalimantan. The Karya Tani ditch witch established 25 years ago, so that impacts of the land management could be identified. The BTLM system was a cycle which comprised natural forest, forest and paddy field, climax paddy field, transition process, and abandoned area. Soil sample were collected from every sequence of the BTLM system. The physical, chemical, mineralogical and micromorphological analyses were carried out on selected sample. The results of the study indicated that there were several changes of the soil characteristics that possibly changed the soil classification results. The pyrites (FeS₂) was dissolved into iron Fe²⁺ and SO₄ = ions and the Fe²⁺ were immediately oxidized and hydrolyzed into iron hydro-oxides. In some cases the iron hydro-oxides coated the remaining pyrites, therefore even the forests had been converted into agriculture lands for about 25 years the pyrites were still remain. The minimum tillage in the BTLM was related to the fact that the existing pyrites were coated by iron hydro-oxides. This coating could break up and the acid could be reproduced if these soils were plowed. It seem that the BTLM system is an adaptive land management system in an ecosystem with the (potential) acid sulphate soils.