Ultisols of “lowlandDipterocarpforest” in East Kalimantan, Indonesia

Abstract

Morphological and physical properties of 35 Typic Paleudults and Typic Hapludults, the major soils of the "Lowland Dipterocarp Forest" in East Kalimantan were investigated. The soil morphology was related to the texture, and occasionally to the geomorphology. The coarse soils were distinguished from the fine ones by the more frequent occurrence of gray and rusty mottles in the epipedons, thicker albic horizons, thinner cutan development in the argillic horizons, weaker mottling in the subsoils, and weaker structure development throughout the solum. Clay migration was more pronounced in the fine soils than in the coarse ones. Silt translocation was detected in the fine soils, but not in the coarse soils. Physical properties were controlled by the texture and depth. Bulk density increased with depth, and was inversely correlated with the clay and carbon contents in each horizon. Fine pore space increased with depth, and was directly correlated with the clay content. Meanwhile the coarse pore space decreased downward, and was inversely correlated with the clay content. Hydraulic conductivity was high in the topsoils and decreased with depth. The soil shrinkage pattern was assumed to be associated with the difference in morphology, and clay and silt migration.

Physico-Chemical Characterization and Mine Soil Genesis in Age Series Coal Mine Overburden Spoil in Chronosequence in a Dry Tropical Environment

“…A negative relation between bulk density and organic C (r=-0.903, p<0.01) of spoil samples collected from different age series of mine overburdens substantiated the concept [7,18,46,47]. Organic C in association with primary soil particle was reported to promote macro aggregation [40,45] and hence, soil bulk density declines.…”

“…Importance of bulk density lies with the fact that it regulates space, air and water availability to soil organisms [43]. A decline in bulk density, with age of mine spoil, can be interpreted as a reduction in soil compactness, because of the development of soil micropore space [44,45]. According to Ohta and Effendi [45], it is the clay fraction, which has an ultimate bearing on the soil bulk density.…”

Potential N2O emissions from leguminous tree plantation soils in the humid tropics

“…Relatively low-clay-content Acrisols have less structure development and high bulk density because soil shrinkage in drier periods is weaker than that of more clayey Acrisols, and particles of sand, silt, and clay are packed closely [Ohta and Effendi, 1992]. Thus in relatively low-clay-content Acrisols, soil porosity declines and drainage is consequently constrained.…”

Biomass Recovery of Naturally Regenerated Vegetation after the 1998 Forest Fire in East Kalimantan, Indonesia

“…The area was originally covered by a lowland dipterocarp forest. The mean annual rainfall is approximately 2,000 mm; the annual mean daily maximum and minimum temperatures are 29.9 and 21.4ºC, respectively 16 ; and the dominated soils are Ultisols 10 . This area was subjected to selective logging prior to 1978 17 .…”