Soil Water Conditions According to Landscape Position and Aboveground Vegetation in an Acacia mangium Plantation in Sabah, Malaysia

JARQ : Japan Agricultural Research Quarterly
ISSN 00213551
書誌レコードID(総合目録DB) AA0068709X
42-01-10.pdf1.04 MB

We studied the soil water dynamics of the humid tropics at a 1.6-ha Acacia mangium stand in Sabah State, northern Borneo, to quantify the effect of landscape position and vegetation on soil water conditions. We monitored the volumetric soil water content (VSW) at a depth of 30 cm at 12 locations in the research plot, every 30 min for 1 year using ADR theta probes. To analyze the drying process, twelve events were selected in the course of the research period when comparatively long intervals without rainfall occurred. The decline in soil water during the drying periods fit linear regressions well when we excluded the data from the first 24 h after the last rain event. The absolute value of the slope of the regression was termed the drying rate (DR). Topographic index, described as ln(α/tanβ) (α = upslope contributing area per unit contour; tanβ = local slope angle) was also determined. The range of the VSW in bottomland was smaller than for other landscape positions, but no significant relationship was observed between the topographic index and the VSW. The median DR was significantly correlated with tree density, and with the topographic index. During a drying period, evapotranspiration was the major factor controlling the soil water regime in this stand. The normalized DR according to tree density was significantly lower in the bottomlands, and described the wet gleyic characteristics of the bottomland well. The DR appeared to be a good indicator for detecting the effects of vegetation and topography on soil water conditions in the humid tropics.

作成者 INAGAKI Masahiro KAMO Koichi YAMADA Tsuyoshi TITIN Jupiri

humid tropics

slope position

soil drying rate

soil moisture

tree density

公開者 Japan International Research Center for Agricultural Sciences
国立情報学研究所メタデータ主題語彙集(資源タイプ) Journal Article
開始ページ 69
終了ページ 76
DOI 10.6090/jarq.42.69
権利 Japan International Research Center for Agricultural Sciences
言語 eng