A Comparative Study of the Use of Organic Carbon and Loss on Ignition in Defining Tropical Organic Soil Materials
| Autor: | E. Van Ranst, Mum Keng Wong, Raphael A.J. Wüst, S. Paramananthan, J.R. Vijiandran, Pei Xiong Lee |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Peat
Soil organic matter Soil Science Soil classification 04 agricultural and veterinary sciences Soil carbon 010501 environmental sciences 01 natural sciences Tropical peat Environmental chemistry Soil water 040103 agronomy & agriculture Histosol 0401 agriculture forestry and fisheries Environmental science Loss on ignition Agronomy and Crop Science 0105 earth and related environmental sciences |
| Zdroj: | Communications in Soil Science and Plant Analysis. 49:626-634 |
| ISSN: | 1532-2416 0010-3624 |
| Popis: | Organic soils or Histosols or peats as they are commonly referred to, are characterized by the presence of large amounts of organic soil materials (OSM), which is commonly quantified by the Walkley and Black (1934) (WB) method to determine the soil organic matter (SOM) using a correction factor of 1.724. SOM of Histosols is also identified through a combustion (loss on ignition, LOI) or elemental C-analysis (with a carbon-nitrogen-sulfur (CNS) analyzer with combustion and gas density detector). These methods were established using temperate and boreal peat deposits and here we demonstrate that tropical peat deposits require a modified approach. Typical SE-Asian tropical lowland peat pedons from rain forest and oil palm settings were sampled and the material analysed using a CNS analyzer, WB-C and LOI. The ratios for LOI:CNS-C for the 20 samples yielded values between 2.00–3.09 with a mean of 2.50 while the LOI:WB-C ratio yielded values from 1.75 to 2.58 with a mean of 1.94. A comparison of these values for topsoils and subsoils showed mean ratios (LOI:WB-C) of 1.94 and 1.89 for topsoils and subsoils, respectively. The forest samples had higher LOI:WB-C ratios than the subsoils from oil palm settings (1.94 vs 1.84). These values suggest that the standard factor of 1.724 to correct OSM to SOM for tropical soils is untenable. The values to convert CNS and WB-C values of tropical topsoils/subsoils to SOM or LOI should be 2.5 or 1.9, respectively. Our results indicate a significant difference in the soil organic carbon (SOC) of tropical lowland peats depending on the method used. |
| Databáze: | OpenAIRE |
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