Publication
 

Heterogeneity of Soil Morphology and Hydrology on the 50 ha Long-Term Ecological Research Plot at Pasoh, Peninsular Malaysia

The soils of the 50 ha long-term Centre for Tropical Forest Science (CTFS) research plot at Pasoh, Peninsular Malaysia were surveyed in detail in 1994—1996 and briefly re-examined in 2005—2006. Pasoh is rain shadowed by mountains to both east and west, and the aseasonal 1800 mm annual rainfall is marginal for an evergreen forest. There is a low ridge of Triassic shale in the north-eastern corner but two thirds of the plot consists of alluvial flats. The ridge is capped by remnants of a laterite (ferricrete) sheet, and the well-drained, brown fine loam over clay soils range from < 50 cm over a sheet of dense gravel laterite on the crest, through moderately dense gravels on midslopes, to deep clays with few gravels on lower slopes. The alluvial sediments are derived from variable mixtures of granite, sandstone and shale. Drainage varies from moderately free on a low (1—3 m) terrace to perennially saturated in low parts of a floodplain. Many of the poorly drained soils are stagnogleys, with mucky surfaces, and very wet, mottled grey upper mineral horizons, overlying moist and less mottled brown subsoils. The ridge soils are moderately dystrophic, and soil depth and available moisture reserves for dry spells appear to be major edaphic constraints. The alluvial soils are also moderately dystrophic, and vary substantially with respect to aeration of root zones. Stagnogleying imposes a particular combination of aeration stresses on young plants, as young seedlings have to cope initially with the saturated upper horizons, but encounter better aerated lower subsoils if they survive and grow. Nutrients are also important, but it is the extent and type of drainage constraints that make Pasoh unusual among CTFS plots.

Tanah di plot kajian jangka panjang 50 ha Pusat Sains Hutan Tropika (CTFS) di Pasoh, Semenanjung Malaysia dikaji dengan terperinci pada tahun 1994—1996 dan diperiksa semula pada 2005—2006. Pasoh terletak di kawasan lindungan hujan di antara banjaran gunung di timur dan barat dengan hujan tak bermusim sebanyak 1800 mm setahun, jumlah yang agak sedikit untuk hutan malar hijau. Terdapat satu banjaran syal rendah berusia Trias di timur laut plot kajian tetapi dua pertiga plot terdiri daripada dataran aluvium. Banjaran dilitupi tinggalan lapisan laterit (ferikret) dan tanah lom halus berwarna perang yang sangat salir di atas lempung. Ia berada < 50 cm dari lapisan padat kelikir laterit di puncak, diikuti kelikir yang sederhana padat di pertengahan banjaran, seterusnya lempung dalam dan sedikit kelikir di kaki banjaran. Enapan aluvium dibentuk daripada campuran batuan granit, batu pasir dan syal. Saliran tanah berubah dari sederhana di teres rendah (1—3 m) hingga agak tepu sepanjang tahun di bahagian rendah dataran banjir. Kebanyakan tanah tidak mempunyai saliran yang baik terbentuk daripada glei genang yang berlumpur dengan horizon mineral sangat berair dan berarau kelabu berada di atas subtanah perang yang lembab dan kurang arau. Tanah banjaran mempunyai distrofi sederhana. Kedalaman tanah dan kandungan simpanan lembapan tersedia semasa musim kering berkemungkinan menjadi halangan edafik yang utama. Tanah aluvium juga mempunyai distrofi sederhana dan pengudaraan zon akarnya berubah-ubah dengan ketara. Glei genang menyebabkan berlakunya tegasan pengudaraan ke atas tumbuhan muda kerana anak-anak pokok terpaksa menghadapi horizon atas yang tepu air tetapi subtanah yang lebih baik pengudaraannya. Walaupun pengaruh nutrien juga penting, taburan dan jenis kekangan saliran dipercayai menjadikan Pasoh agak berbeza daripada plot CTFS yang lain.

Abstract in English & Malay; article in English only. 

Authors: 
Y. Adzmi, W.C. Suhaimi, M.S. Amir Husni, H. Mohd Ghazali, S.K. Amir, & I. Baillie
Journal: 
Journal of Tropical Forest Science
Year: 
2010
Volume: 
22
Issue: 
1
Pages: 
21-35
Site: 
Pasoh