Properties of peat soil formed in lacustrine plains surrounded by tectonic hills in Papua Highland

Peat soils in Papua highlands are unique because they formed in lacustrine plains surrounded by tectonic hills. However, there is no information about the characteristics of these peat soils. Thus, the purpose of this study was to assess properties of these specific peat soils. Four selected peat soils located at an altitude between 1548 to 1782 m asl were studied for their morphology. A total of 16 samples were taken for analysis in the laboratory. The results showed that peat soils were derived from reed-sedges and ferns. The ash content in extremely deep peat soils is 42-337 mg kg⁻¹, while moderate peat soils are 179 to 648 mg kg⁻¹. Soil acidity ranges from very acid to slightly acid. Base saturation is classified as low to moderate (30 to 62%). These peat soils received Ca and Al enrichment from the surrounding tectonic hills. Interesting findings in these soils are high exchangeable Ca (21.11 to 42.62 cmol_c kg⁻¹) and high potential P (13 to 1,104 mg kg⁻¹). Chemical properties of peat soils in Papua are more fertile in highlands than lowland with implication of lower input application in the highland. The exchangeable Al should be considered when these peat soils are cleared for agriculture.