Eurasian Journal of Soil Science

Abstract

Limited information is available on the pedology of highly weathered soils derived from ophiolitic rocks in the Philippines. This study evaluated red, highly weathered soils across the ophiolitic landscape of Eastern Samar. Five soil profiles were described and sampled for laboratory analysis. The geochemical composition of the parent materials ranged from mafic to ultramafic. The soils were acidic [pH(H₂O) = 4.97–6.45; pH(CaCl₂) = 3.95–5.96] and contained low concentrations of available P (trace–1.14 mg kg⁻¹), exchangeable K (trace–0.23 cmolc kg⁻¹), Ca (trace–12.66 cmolc kg⁻¹), and Na (trace), together with low Ca/Mg ratios (0.1–41.7). Profile 2 had comparatively high exchangeable Ca concentrations, particularly in deeper horizons. Ca/Mg ratios increased with depth in Profiles 2 and 3 but decreased in Profile 5. In Profiles 1 and 4, Ca/Mg ratios were very low and could not be calculated in several subsurface horizons because exchangeable Ca and/or Mg occurred at trace levels. Extractable Ni concentrations ranged from 0.16 to 22.40 mg kg⁻¹, with the highest concentration occurring in the Bo2 horizon of Profile 4, indicating contributions from ultramafic materials, Ni accumulation, and adsorption onto Fe (oxyhydr)oxides during weathering. The warm, humid climate, highly weatherable ophiolitic parent material, stable, well-drained topography, and original rainforest vegetation promoted the formation of highly weathered Ultisols and Oxisols. Low OM (0.36%–3.60%) and total N (0.04%–0.25%) contents may reflect anthropogenic effects, particularly periodic burning associated with shifting cultivation. The CIA (55.56–99.31), CIW (55.63–99.58), MWPI (0.14–7.44), and Vogt ratio (1.08–63.95) indicated advanced weathering and substantial losses of major cations. These findings demonstrate that ophiolitic soils under humid tropical conditions undergo intense weathering and leaching, resulting in marked profile-scale variation during pedogenic development.

Keywords

Geochemistry, soil characteristics, ophiolites, ultramafic soils, Oxisols, Ultisols.

References

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<p>Anderson, D.H., Hawkes, H.E., 1958. Relative mobility of the common elements in weathering of some schist and granite areas. <em>Geochimica et Cosmochimica Acta</em> 14(3): 204&ndash;210.</p>

<p>Asio, V.B., 1996. Characteristics, weathering, formation and degradation of soils from volcanic rocks in Leyte, Philippines. PhD dissertation, University of Hohenheim, Institute of Soil Science and Site Ecology, Stuttgart, Germany.</p>

<p>Asio, V.B., Jahn, R., 2007. Weathering of basaltic rock and clay mineral formation in Leyte, Philippines. <em>Philippine Agricultural Scientist</em> 90: 204&ndash;212.</p>

<p>Baillie, I., Evangelista, P., Inciong, N., 2000. Differentiation of upland soils on the Palawan ophiolitic complex, Philippines. <em>Catena</em> 39(4): 283&ndash;299.</p>

<p>Barbieri, M., 2016. The importance of enrichment factor (EF) and geoaccumulation index (Igeo) to evaluate soil contamination. <em>Journal of Geology &amp; Geophysics</em> 5(1): 237.</p>

<p>Barnes, S.J., Roeder, P.L., 2001. The range of spinel compositions in terrestrial mafic and ultramafic rocks. <em>Journal of Petrology</em> 42(12): 2279&ndash;2302.</p>

<p>Bern, C.R., Walton-Day, K., Naftz, D.L., 2019. Improved enrichment factor calculations through principal component analysis: Examples from soils near breccia pipe uranium mines, Arizona, USA. <em>Environmental Pollution</em> 248: 90&ndash;100.</p>

<p>Boyd, R.S., Kruckeberg, A.R., Rajakaruna, N., 2009. Biology of ultramafic rocks and soils: Research goals for the future. <em>Northeastern Naturalist</em> 16(sp5): 422&ndash;440.</p>

<p>Cascante, M.D., Wu, C.Y., Yang, C.Y., Hum, H.Z., Hseu, Z.Y., 2025. Parent material, elemental composition, and pedogenic processes in ophiolitic soils in Eastern Taiwan. <em>Pertanika Journal of Tropical Agricultural Science</em> 48(3): 991&ndash;1017.</p>

<p>Chesworth, W., 1973. The residua system of chemical weathering: A model for the chemical breakdown of silicate rocks at the surface of the Earth. <em>European Journal of Soil Science</em> 24(1): 69&ndash;81.</p>

<p>Coleman, R.G., 1977. Ophiolites: Ancient Oceanic Lithosphere? Springer-Verlag, Berlin, Germany, 229 p.</p>

<p>Coronas, J., 1920. The Climate and Weather of the Philippines, 1903&ndash;1918. Bureau of Printing, Manila, Philippines.</p>

<p>D&rsquo;Amico, M.E., 2009. Soil ecology and pedogenesis on ophiolitic materials in the Western Alps (Mont Avic Natural Park, northwestern Italy): Soil properties and their relationships with substrate, vegetation and biological activity. Doctoral dissertation.</p>

<p>Dilek, Y., Furnes, H., 2014. Ophiolites and their origins. <em>Elements</em> 10(2): 93&ndash;100.</p>

<p>Dimalanta, C., Suerte, L., Yumul, G., Tamayo, R., Ramos, E., 2006. A Cretaceous supra-subduction oceanic basin source for Central Philippine ophiolitic basement complexes: Geological and geophysical constraints. <em>Geosciences Journal </em>10(3): 305&ndash;320.</p>

<p>Edwards, P.J., 1998. Sulfur cycling, retention, and mobility in soils: A review. General Technical Report NE-250. Radnor, PA: U.S. Department of Agriculture, Forest Service, Northeastern Research Station. 18 p.</p>

<p>Galey, M.L., van der Ent, A., Iqbal, M.C.M., Rajakaruna, N., 2017. Ultramafic geoecology of South and Southeast Asia. <em>Botanical Studies</em> 58(1): 18.</p>

<p>Galgo, S.J.C., Asio, V.B., 2022. Properties, geochemical composition, and fertility of highly weathered soils in Central Philippines. <em>Eurasian Journal of Soil Science</em> 11(2): 113&ndash;125.</p>

<p>Gao, Y., Ma, M., Yang, T., Chen, W., Yang, T., 2018. Global atmospheric sulfur deposition and associated impaction on nitrogen cycling in ecosystems. <em>Journal of Cleaner Production</em> 195: 1&ndash;9.</p>

<p>Goldich, S.S., 1938. A study in rock-weathering. <em>Journal of Geology</em> 46(1): 17&ndash;58.</p>

<p>Gupta, B., Chandra Pathak, D.G., 2025. Role of nickel in plants: A review. <em>Indian Journal of Applied &amp; Pure Biology</em> 40: 2175&ndash;2181.</p>

<p>Harnois, L., 1988. The CIW index: A new chemical index of weathering. <em>Sedimentary Geology</em> 55(3&ndash;4): 319&ndash;322.</p>

<p>Hseu, Z.Y., 2018. Biogeochemistry of Serpentine Soils. Nova Science Publishers, New York, USA.</p>

<p>ISRIC, 1998. World Reference Base for Soil Resources. World Soil Resources Reports No. 84. Food and Agriculture Organization of the United Nations, Rome, Italy. Available at [Access date: 17.03.2026]: https://www.fao.org/4/w8594e/w8594e00.htm</p>

<p>Jahn, R., Blume, H.P., Asio, V.B., Spaargaren, O., Schad, P., 2006. Guidelines for Soil Description. 4th ed. Food and Agriculture Organization of the United Nations, Rome, Italy. Available at [Access date: 17.03.2026]: https://www.fao.org/4/a0541e/a0541e.pdf</p>

<p>Jones, J.B., Jr., 2001. Laboratory Guide for Conducting Soil Tests and Plant Analysis. CRC Press, Boca Raton, FL, USA. 384p.</p>

<p>Kolb, A., 1942. Die Kulturschichtung auf den Philippinen. <em>Geographische Zeitschrift</em> 48(1/2): 1&ndash;20.</p>

<p>K&ouml;ppen, W., 1918. Klassifikation der Klimate nach Temperatur, Niederschlag und Jahreslauf. <em>Petermanns Geographische Mitteilungen</em> 64: 193&ndash;203, 243&ndash;248.</p>

<p>Kumar, J., 2023. Nickel availability, deficiency and toxicity in soils and plants: A review. <em>International Journal of Applied Research</em> 9(8): 265&ndash;272.</p>

<p>Kumar, P., Khandelwal, D., Kanwar, V., Mukherjee, S., 2025. Geochemical and mineralogical analysis of ophiolitic and sedimentary formations in Middle Andaman. <em>Discover Geoscience</em> 3(1): 97.</p>

<p>Le Bas, M.J., Streckeisen, A.L., 1991. The IUGS systematics of igneous rocks. <em>Journal of the Geological Society</em> 148(5): 825&ndash;833.</p>

<p>Le Maitre, R.W., Streckeisen, A., Zanettin, B., Le Bas, M.J., Bonin, B., Bateman, P., 2002. Igneous Rocks: A Classification and Glossary of Terms: Recommendations of the International Union of Geological Sciences Subcommission on the Systematics of Igneous Rocks. Cambridge University Press, Cambridge, UK.</p>

<p>Lindsay, W.L., Martens, D.C., 1990. Testing soils for copper, iron, manganese, and zinc. In: Westerman, R.L. (Ed.), Soil Testing and Plant Analysis. 3rd ed. Soil Science Society of America, Madison, WI, USA, pp. 229&ndash;264.</p>

<p>Loska, K., Wiechuła, D., Pelczar, J., 2005. Application of enrichment factor to assessment of zinc enrichment/depletion in farming soils. <em>Communications in Soil Science and Plant Analysis</em> 36(9&ndash;10): 1117&ndash;1128.</p>

<p>Madulid, D.A., Agoo, E.M.G., 1997. Assessment of the vegetation of Philippine mountains on ultramafic rocks. In: The Ecology of Ultramafic and Metalliferous Areas. Documents Scientifiques et Techniques III/2, ORSTOM,&nbsp; Jaffr&eacute;, T., Reeves, R.D., Becquer, T. (Eds.), Noum&eacute;a, New Caledonia.</p>

<p>Maleknia, P., Mazhari, S.A., Ugwonoh, N., Czig&aacute;ny, S., Kasina, M., Myovela, J.L., 2025. Assessment of the concentration, mobility, and bioavailability of Co, Cr, and Ni in soils from the West Sabzevar ophiolitic complex, Iran. <em>Journal of Asian Earth Sciences: X</em> 14: 100203.</p>

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<p>Murphy, J., Riley, J.P., 1962. A modified single solution method for the determination of phosphate in natural waters. <em>Analytica Chimica Acta</em> 27: 31&ndash;36.</p>

<p>Navarrete, I.A., Asio, V.B., Jahn, R., Tsutsuki, K., 2007. Characteristics and genesis of two strongly weathered soils in Samar, Philippines. <em>Australian Journal of Soil Research</em> 45(3): 153&ndash;163.</p>

<p>Navarrete, I.A., Gabiana, C.C., Dumo, J.R.E., Salmo, S.G., III, Guzman, M.A.L.G., Valera, N.S., Espiritu, E.Q., 2017. Heavy metal concentrations in soils and vegetation in urban areas of Quezon City, Philippines. <em>Environmental Monitoring and Assessment</em> 189(4): 145.</p>

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<p>Oze, C., Fendorf, S., Bird, D.K., Coleman, R.G., 2004. Chromium geochemistry of serpentine soils. <em>International Geology Review </em>46(2): 97&ndash;126.</p>

<p>Palin, R.M., Santosh, M., Cao, W., Li, S.S., Hern&aacute;ndez-Uribe, D., Parsons, A., 2020. Secular change and the onset of plate tectonics on Earth. <em>Earth-Science Reviews</em> 207: 103172.</p>

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Abstract

Limited information is available on the pedology of highly weathered soils derived from ophiolitic rocks in the Philippines. This study evaluated red, highly weathered soils across the ophiolitic landscape of Eastern Samar. Five soil profiles were described and sampled for laboratory analysis. The geochemical composition of the parent materials ranged from mafic to ultramafic. The soils were acidic [pH(H₂O) = 4.97–6.45; pH(CaCl₂) = 3.95–5.96] and contained low concentrations of available P (trace–1.14 mg kg⁻¹), exchangeable K (trace–0.23 cmolc kg⁻¹), Ca (trace–12.66 cmolc kg⁻¹), and Na (trace), together with low Ca/Mg ratios (0.1–41.7). Profile 2 had comparatively high exchangeable Ca concentrations, particularly in deeper horizons. Ca/Mg ratios increased with depth in Profiles 2 and 3 but decreased in Profile 5. In Profiles 1 and 4, Ca/Mg ratios were very low and could not be calculated in several subsurface horizons because exchangeable Ca and/or Mg occurred at trace levels. Extractable Ni concentrations ranged from 0.16 to 22.40 mg kg⁻¹, with the highest concentration occurring in the Bo2 horizon of Profile 4, indicating contributions from ultramafic materials, Ni accumulation, and adsorption onto Fe (oxyhydr)oxides during weathering. The warm, humid climate, highly weatherable ophiolitic parent material, stable, well-drained topography, and original rainforest vegetation promoted the formation of highly weathered Ultisols and Oxisols. Low OM (0.36%–3.60%) and total N (0.04%–0.25%) contents may reflect anthropogenic effects, particularly periodic burning associated with shifting cultivation. The CIA (55.56–99.31), CIW (55.63–99.58), MWPI (0.14–7.44), and Vogt ratio (1.08–63.95) indicated advanced weathering and substantial losses of major cations. These findings demonstrate that ophiolitic soils under humid tropical conditions undergo intense weathering and leaching, resulting in marked profile-scale variation during pedogenic development.

Keywords: Geochemistry, soil characteristics, ophiolites, ultramafic soils, Oxisols, Ultisols.

References

Alloway, B.J., 2012. Sources of heavy metals and metalloids in soils. In: Heavy Metals in Soils: Trace Metals and Metalloids in Soils and Their Bioavailability. Alloway, B.J. (Ed.), 3rd ed. Springer, Dordrecht, the Netherlands, pp. 11–50.

Anderson, D.H., Hawkes, H.E., 1958. Relative mobility of the common elements in weathering of some schist and granite areas. Geochimica et Cosmochimica Acta 14(3): 204–210.

Asio, V.B., 1996. Characteristics, weathering, formation and degradation of soils from volcanic rocks in Leyte, Philippines. PhD dissertation, University of Hohenheim, Institute of Soil Science and Site Ecology, Stuttgart, Germany.

Asio, V.B., Jahn, R., 2007. Weathering of basaltic rock and clay mineral formation in Leyte, Philippines. Philippine Agricultural Scientist 90: 204–212.

Baillie, I., Evangelista, P., Inciong, N., 2000. Differentiation of upland soils on the Palawan ophiolitic complex, Philippines. Catena 39(4): 283–299.

Barbieri, M., 2016. The importance of enrichment factor (EF) and geoaccumulation index (Igeo) to evaluate soil contamination. Journal of Geology & Geophysics 5(1): 237.

Barnes, S.J., Roeder, P.L., 2001. The range of spinel compositions in terrestrial mafic and ultramafic rocks. Journal of Petrology 42(12): 2279–2302.

Bern, C.R., Walton-Day, K., Naftz, D.L., 2019. Improved enrichment factor calculations through principal component analysis: Examples from soils near breccia pipe uranium mines, Arizona, USA. Environmental Pollution 248: 90–100.

Boyd, R.S., Kruckeberg, A.R., Rajakaruna, N., 2009. Biology of ultramafic rocks and soils: Research goals for the future. Northeastern Naturalist 16(sp5): 422–440.

Cascante, M.D., Wu, C.Y., Yang, C.Y., Hum, H.Z., Hseu, Z.Y., 2025. Parent material, elemental composition, and pedogenic processes in ophiolitic soils in Eastern Taiwan. Pertanika Journal of Tropical Agricultural Science 48(3): 991–1017.

Chesworth, W., 1973. The residua system of chemical weathering: A model for the chemical breakdown of silicate rocks at the surface of the Earth. European Journal of Soil Science 24(1): 69–81.

Coleman, R.G., 1977. Ophiolites: Ancient Oceanic Lithosphere? Springer-Verlag, Berlin, Germany, 229 p.

Coronas, J., 1920. The Climate and Weather of the Philippines, 1903–1918. Bureau of Printing, Manila, Philippines.

D’Amico, M.E., 2009. Soil ecology and pedogenesis on ophiolitic materials in the Western Alps (Mont Avic Natural Park, northwestern Italy): Soil properties and their relationships with substrate, vegetation and biological activity. Doctoral dissertation.

Dilek, Y., Furnes, H., 2014. Ophiolites and their origins. Elements 10(2): 93–100.

Dimalanta, C., Suerte, L., Yumul, G., Tamayo, R., Ramos, E., 2006. A Cretaceous supra-subduction oceanic basin source for Central Philippine ophiolitic basement complexes: Geological and geophysical constraints. Geosciences Journal 10(3): 305–320.

Edwards, P.J., 1998. Sulfur cycling, retention, and mobility in soils: A review. General Technical Report NE-250. Radnor, PA: U.S. Department of Agriculture, Forest Service, Northeastern Research Station. 18 p.

Galey, M.L., van der Ent, A., Iqbal, M.C.M., Rajakaruna, N., 2017. Ultramafic geoecology of South and Southeast Asia. Botanical Studies 58(1): 18.

Galgo, S.J.C., Asio, V.B., 2022. Properties, geochemical composition, and fertility of highly weathered soils in Central Philippines. Eurasian Journal of Soil Science 11(2): 113–125.

Gao, Y., Ma, M., Yang, T., Chen, W., Yang, T., 2018. Global atmospheric sulfur deposition and associated impaction on nitrogen cycling in ecosystems. Journal of Cleaner Production 195: 1–9.

Goldich, S.S., 1938. A study in rock-weathering. Journal of Geology 46(1): 17–58.

Gupta, B., Chandra Pathak, D.G., 2025. Role of nickel in plants: A review. Indian Journal of Applied & Pure Biology 40: 2175–2181.

Harnois, L., 1988. The CIW index: A new chemical index of weathering. Sedimentary Geology 55(3–4): 319–322.

Hseu, Z.Y., 2018. Biogeochemistry of Serpentine Soils. Nova Science Publishers, New York, USA.

ISRIC, 1998. World Reference Base for Soil Resources. World Soil Resources Reports No. 84. Food and Agriculture Organization of the United Nations, Rome, Italy. Available at [Access date: 17.03.2026]: https://www.fao.org/4/w8594e/w8594e00.htm

Jahn, R., Blume, H.P., Asio, V.B., Spaargaren, O., Schad, P., 2006. Guidelines for Soil Description. 4th ed. Food and Agriculture Organization of the United Nations, Rome, Italy. Available at [Access date: 17.03.2026]: https://www.fao.org/4/a0541e/a0541e.pdf

Jones, J.B., Jr., 2001. Laboratory Guide for Conducting Soil Tests and Plant Analysis. CRC Press, Boca Raton, FL, USA. 384p.

Kolb, A., 1942. Die Kulturschichtung auf den Philippinen. Geographische Zeitschrift 48(1/2): 1–20.

Köppen, W., 1918. Klassifikation der Klimate nach Temperatur, Niederschlag und Jahreslauf. Petermanns Geographische Mitteilungen 64: 193–203, 243–248.

Kumar, J., 2023. Nickel availability, deficiency and toxicity in soils and plants: A review. International Journal of Applied Research 9(8): 265–272.

Kumar, P., Khandelwal, D., Kanwar, V., Mukherjee, S., 2025. Geochemical and mineralogical analysis of ophiolitic and sedimentary formations in Middle Andaman. Discover Geoscience 3(1): 97.

Le Bas, M.J., Streckeisen, A.L., 1991. The IUGS systematics of igneous rocks. Journal of the Geological Society 148(5): 825–833.

Le Maitre, R.W., Streckeisen, A., Zanettin, B., Le Bas, M.J., Bonin, B., Bateman, P., 2002. Igneous Rocks: A Classification and Glossary of Terms: Recommendations of the International Union of Geological Sciences Subcommission on the Systematics of Igneous Rocks. Cambridge University Press, Cambridge, UK.

Lindsay, W.L., Martens, D.C., 1990. Testing soils for copper, iron, manganese, and zinc. In: Westerman, R.L. (Ed.), Soil Testing and Plant Analysis. 3rd ed. Soil Science Society of America, Madison, WI, USA, pp. 229–264.

Loska, K., Wiechuła, D., Pelczar, J., 2005. Application of enrichment factor to assessment of zinc enrichment/depletion in farming soils. Communications in Soil Science and Plant Analysis 36(9–10): 1117–1128.

Madulid, D.A., Agoo, E.M.G., 1997. Assessment of the vegetation of Philippine mountains on ultramafic rocks. In: The Ecology of Ultramafic and Metalliferous Areas. Documents Scientifiques et Techniques III/2, ORSTOM,  Jaffré, T., Reeves, R.D., Becquer, T. (Eds.), Nouméa, New Caledonia.

Maleknia, P., Mazhari, S.A., Ugwonoh, N., Czigány, S., Kasina, M., Myovela, J.L., 2025. Assessment of the concentration, mobility, and bioavailability of Co, Cr, and Ni in soils from the West Sabzevar ophiolitic complex, Iran. Journal of Asian Earth Sciences: X 14: 100203.

Miyashiro, A., 1975. Classification, characteristics, and origin of ophiolites. Journal of Geology 83(2): 249–281.

Murphy, J., Riley, J.P., 1962. A modified single solution method for the determination of phosphate in natural waters. Analytica Chimica Acta 27: 31–36.

Navarrete, I.A., Asio, V.B., Jahn, R., Tsutsuki, K., 2007. Characteristics and genesis of two strongly weathered soils in Samar, Philippines. Australian Journal of Soil Research 45(3): 153–163.

Navarrete, I.A., Gabiana, C.C., Dumo, J.R.E., Salmo, S.G., III, Guzman, M.A.L.G., Valera, N.S., Espiritu, E.Q., 2017. Heavy metal concentrations in soils and vegetation in urban areas of Quezon City, Philippines. Environmental Monitoring and Assessment 189(4): 145.

Nelson, D.W., Sommers, L.E., 1996. Total carbon, organic carbon, and organic matter. In: Methods of Soil Analysis, Part 3: Chemical Methods. Sparks, D.L., Page, A.L., Helmke, P.A., Loeppert, R.H., Soltanpour, P.N., Tabatabai, M.A., Johnston, C.T., Sumner, M.E. (Eds.), SSSA Book Series No. 5. Soil Science Society of America and American Society of Agronomy, Madison, WI, USA, pp. 961–1010.

Nesbitt, H.W., Young, G.M., 1982. Early Proterozoic climates and plate motions inferred from major element chemistry of lutites. Nature 299(5885): 715–717.

Olguera, D.T., Asio, V.B., 2025. Application of soil development indices for the evaluation of old soils in Samar Island, Philippines. Philippine Journal of Science 154(5): 1171-1183.

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