Classification of Acid Sulfate Soils of Peninsular Malaysia

Acid sulfate soils form an important group of soils in Peninsular MaLaysia, particularly on the West Coast. These soils developed over marine, estuarine and brackish water deposits can be divided into two groups - the potential acid sulfate soils and the true acid sulfate soils using the definitions established in Soil Taxonomy. The classification of these soils in accordance to the Malaysian system is discussed. The Malaysian system though based on the concepts of Soil Taxonomy has been modified to suit local conditions. Two sequences of acid sulfate soils have been recognized in Peninsular Malaysia. A key to the identification of these acid sulfate soils is also presented in the paper

Acidity and Charge Characteristics of Marine Alluvial Soils from Carey Islands, Selangor

Six soil series from Carey Island were investigated to determine their acidity and charge characteristics. The study showed that the soils contained high amounts of basic cations, Al and S042-, which were reflected by their low pH and high electrical conductivity. The soils were highly buffered below pH 5.5 and this was found to be highly correlated to Al content. Further, it was found that negative charges on the clay surfaces increased with increase in soil pH. These observations' are contrary to the fact that the clay minerals in these soils are of the permanent charge type

Morphology, Mineralogy and Chemistry of an Ex-Mining Land in Ipoh, Perak

A study was carried out to characterize the 20.3 ha of ex-mining land at Kg. Kepayang Baru, Ipoh. The study shows that the ex-mining land can be classified into three groups i. e., sandy, clayey and a mixture of sandy and clayey deposits. The bases, organic carbon, phosphorus and nitrogen contents are very low. The cation exchange capacity is low, but pH is very high. The dominant minerals in the clay fraction are kaolinite, mica and chlorite

Mineralogy and Surface Charge Properties of two Acid Sulfate Soils from Peninsular Malaysia

Two acid sulfate soils sampled from an oil palm estate in Perak, Peninsular Malaysia, were studied. The soils were characterized by a low pH and the presence of yellowish mottles, which were identified as jarosite and/or natrojarosite. Other minerals present were kaolinite, mica, mica-smectite and smectite. The negative charges on the soil surface were found to increase significantly with an increase in pH. This increase was not related to the presence of oxides and/or hydroxides as these materials were present in very small amounts in the soils. On account of the increase in the negative charges with an increase in pH, it is suggested that CEC of acid sulfate soils be determined at soil pH to give a better reflection of the soil properties. Further, it was found that the soils were highly buffered at pH 3 - 5. The strong buffering at this pH range was related to the presence of high amounts ofaluminium in the soil

Penentuan faktor-faktor tanah ke atas tumbesaran gajus di kawasan tanah Bris : bahagian I

Penyelidikan mengenai gajus adalah amat kurang. Oleh yang demikian, satu kajian ladang telah dijalankan untuk menentukan perkaitan antara kedalaman lapisan keras spodik, iaitu ciri semulajadi tanah, dan paras kandungan bahan organan ke atas tumbesaran gajus. Kajian ini dijalankan di ladang gajus Perusahaan Gajus Malaysia (C/MA). Besut, di mana jenis-jenis tanah berasaskan kedalaman horizon spodik telah ditentukan terlebih dahulu. Teknik-teknik ringkas, yang direka khas untuk kajian ladang telah digunakan. Kedalaman lapisan keras spodik tidak menunjukkan kesan yang bererti ke atas tumbesaran gajus yang diukur dari segi ke tinggian pokok dan luas permukaan sudur pokok. Ini adalah kerana pokok tersebut tidak mempunyai sistem akar yang dalam. Walaubagaimana pun, kandungan bahan organan tanah memberikan kesan yang sangat bererti ke atas ketinggian pokok serta luas permukaan sudur pokok dan memberikan angkali korelasi r = 0.536 dan r = 0.495 (P < 0.01) tiap-tiap satunya. Seterusnya bahan organan tanah dipengaruhi secara tidak langsung oleh kedalaman lapisan keras spodik seperti yang ditunjukkan oleh angkali korelasi yang negatif (r =-·0.364; P < 0.05)

Distribution of VA Mycorrhizal Spores in Sandy Beach Soils under Cashew

Surface horizons (0-15 em) of sandy beach soils from Besut and Kuantan, (Malaysia) under cashew (Anacardium occidentale L) were sampled for Vesicular-Arbuscular Mycorrhizal (VAM) spores. Isolation of VAM spores were made from both the Rudua and Jambu series in Besut as well as the Rudua and Baging series in Kuantan. There were more spores isolated from the Kuantan than the Besut areas. The results also indiate a positive relationship between spore number to percent organic matter present in the topsoil. The abundant spores isolated from the Kuantan areas (in contrast to Besut) could have some significance in the P nutrition of cashew and probably explain the yield differences existing between these two areas

A comparative study of the use of organic carbon and loss on ignition in defining tropical organic soil materials

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

Contrasting vulnerability of drained tropical and high-latitude peatlands to fluvial loss of stored carbon

Carbon sequestration and storage in peatlands rely on consistently highwater tables. Anthropogenic pressures including drainage, burning, land conversion for agriculture, timber, and biofuel production, cause loss of peat-forming vegetation and exposure of previously anaerobic peat to aerobic decomposition. This can shift peatlands from net CO2 sinks to large CO2 sources, releasing carbon held for millennia. Peatlands also export significant quantities of carbon via fluvial pathways, mainly as dissolved organic carbon (DOC). We analyzed radiocarbon (14C) levels of DOC in drainage water from multiple peatlands in Europe and Southeast Asia, to infer differences in the age of carbon lost from intact and drained systems. In most cases, drainage led to increased release of older carbon from the peat profile but withmarked differences related to peat type. Very low DOC-14C levels in runoff from drained tropical peatlands indicate loss of very old (centuries to millennia) stored peat carbon. High-latitude peatlands appear more resilient to drainage; 14C measurements from UK blanket bogs suggest that exported DOC remains young (500 year) carbon in high-latitude systems. Rewetting at least partially offsets drainage effects on DOC age

Effects of cross-section on infiltration and seepage in permeable stormwater channels

Factors affecting the infiltration rate have been studied fairly well by many researches; however, the effects of the cross-section of a permeable stormwater channel on the surface water depth reduction due to infiltration and seepage have largely been neglected. In the present study, towards improving the efficiency of permeable channels, the effects of the three components of a trapezoidal section, namely, the water depth, side slope, and base width, on the infiltration and unsteady seepage rates were investigated. Laboratory studies using models of the channel with unsaturated soil were performed under ponding condition using various initial water levels, base widths, and side slopes for two soil textures, namely, sandy loam and loamy sand. The results showed that the rate of surface water depth reduction by infiltration and seepage increases with increasing water level irrespective of the base width and side slope. In addition, an increase of the side slope increases the infiltration rate, with the effect becoming more significant with increasing initial water level, while the effect of varying the base width is insignificant