Ultrabasic Soils Research Articles

Assessment of Heavy Metal Pollution Using the Geo-accumulation Index (I-Geo), Pollution Load Index (PLI) and Potential Ecological Risk Index (RI) in Paddy Field Soils Adjacent to Ultrabasic Soils

Assessment of Heavy Metal Pollution Using the Geo-accumulation Index (I-Geo), Pollution Load Index (PLI) and Potential Ecological Risk Index (RI) in Paddy Field Soils Adjacent to Ultrabasic Soils

Assessment of Heavy Metal Pollution Using the Geo-accumulation Index (I-Geo), Pollution Load Index (PLI) and Potential Ecological Risk Index (RI) in Paddy Field Soils Adjacent to Ultrabasic Soils

The content of heavy metals was appraised at paddy fields, from a total of 54 soil samples gathered from two locations in Ranau, Sabah and one from the UKM experimental paddy plot in Peninsular Malaysia, during2014 and 2015. Through an appraisal evaluate of contamination using the Index of Geo-accumulation (I geo) it was noted that Chromium and Nickel levels in Ranau field 1 came under grade 6 (I-geo > 5 is considered to be very contaminated), showing that the soil was heavily tainted with Cr and Ni, whilst Cobalt was discovered to be at the grade 3 level (medium to strong contamination). On the other hand, Ranau field 2's I-geo for other metals came under grade 1(which means medium to no contamination), highlighting the fact that the soils in these areas were tainted with the examined metals, while the control field was found to be grade 0 (no contamination). Ranau field 1 showed strong levels of the contamination factor (CF) for Co, Cr, and Ni, and its Pollution Load Index was(PLI) was> 1, denoting a steady degradation in the area, with high levels of pollution compared to those in the other tested areas. The average monomial ecological risk for Ni was found to be between (40 – 80), highlighting that Ni contamination was considered to be of medium danger to the surrounding environment. Through the Potential Ecological Risk Index, it was seen that Ni was a likely hazard and presented a substantial danger. The RI values for the test sites were as follows: season 2015 (2.89) < control for season 2014 (3.18).

Use of magnetic susceptibility to assess metals concentration in soils developed on a range of parent materials

This research was conducted to evaluate the utilization of magnetic susceptibility measurements in the assessment of metal concentrations in soils developed on a range of parent materials in northwestern Iran. Eighty surface soil samples were collected from eight parent rocks including ultrabasic rocks, basalt, andesite, granite, marl, limestone, Qom formation, and shale. The collected samples were assessed to determine magnetic susceptibility at low frequency (χlf) and concentrations of some metals comprising chromium (Cr), iron (Fe), copper (Cu), nickel (Ni), zinc (Zn), cobalt (Co), and manganese (Mn). The results showed that the highest levels of metals and χlf were observed in basic and ultrabasic soils. Strong positive correlations (P < 0.01) detected between χlf and Fe (0.87), Mn (0.78), Zn (0.74), Ni (0.90), Co (0.78), and Cr (0.90) in all samples indicated a potential for using magnetic susceptibility in semi-quantitative estimation of metal concentrations in soils of natural ecosystems. Multiple linear regression between metal contents and χlf showed that Ni, Zn, Mn, and Co could explain 77% of the total variance in χlf in the study area. K-means cluster analysis categorized the studied soils into three groups based on metals and χlf variability. Clustering of soils based on their parent rocks and use of further magnetic measures, i.e., saturation isothermal remanent magnetization (SIRM), isothermal remanent magnetization (IRM100mT) and natural remanent magnetization (NRM) are expected to improve the accuracy of metal concentration predictions in natural soils of the study area.

Contrasting effects of exogenous phosphorus application on N2O emissions from two tropical forest soils with contrasting phosphorus availability.

An incubation study was conducted to test the effects of phosphorus (P) addition on nitrous oxide (N2O) emissions from the soils taken from two tropical rain forests established on different parent materials [meta-sedimentary (MS) and ultrabasic (UB) rock] on Mt. Kinabalu, Borneo. Earlier studies suggest that the forest on UB soils is more strongly limited by P than that on MS soils is. In MS soils, P addition significantly reduced N2O emissions. Since neither ammonium (NH4+) nor nitrate (NO3−) contents were reduced by P addition, we assumed that the decrease in N2O emissions were not due to the previously-reported mechanism: P addition stimulated microbial nitrogen (N) immobilization and collateral inorganic N consumption, reducing resources for producing N2O. Since P addition enhanced the ratios of microbial biomass to CO2 and N2O emissions (indicators of nitrifying and/or denitrifying respiratory efficiency), it was suggested that the N required for the respiration of nitrifying and/or denitrifying bacteria was reduced, leading to reduced N2O emissions. On the other hand, P addition had no effects on N2O emissions in UB soils. The respiratory efficiency did not change significantly by P addition, possibly because the microbial community in the highly-P-depleted UB soils shifted by P addition, with which the enhancement of respiration efficiency did not co-vary. We concluded that (1) P addition may control N2O emissions through increasing respiratory efficiency, and (2) the effects may be different depending on the differences in P availability.

Association of organic matter with iron and aluminum across a range of soils determined via selective dissolution techniques coupled with dissolved nitrogen analysis

Strong correlations of soil total organic carbon (OC) with iron and aluminum phases reported frequently make it important to quantify these organic matter (OM) associations, but selective extractants sometimes contain OC. Soil nitrogen is often predominantly organic and might serve as a proxy for OM. We therefore investigated nitrogen associations with Fe and Al using several selective extractants that use reductive, complexation, and alkaline approaches. Total dissolved nitrogen (TDN) correlated strongly with extracted Fe and Al across seventeen samples, including highly- and weakly-weathered soils, iron-rich ultrabasic soils, podzolic, and volcanic soils. Typically a quarter to a third of total soil nitrogen was dissolved by the various extractions, though higher fractions (up to 60%) were found in spodic-horizon and volcanic surface-horizon samples. Similar proportions were found for OC, using three OC-free extractants, indicating that TDN provides a useful surrogate for assessing OM partitioning via extractants that contain OC. Use of TDN:metal ratios in extractant solutions allows estimation of extracted OM that could have been sorptively associated with metal oxide/hydroxides and poorly-crystalline aluminosilicates. These ratios were often high in extractions targeted at these adsorbents, and imply that usually most of the extracted TDN consists instead of organo–metal complexes. The dynamics of these complexes may have stronger control on accumulation/remobilization of soil OM than those of metal oxyhydroxides and poorly-crystalline aluminosilicates.

Interactive influences of climate and parent material on soil microbial community structure in Bornean tropical forest ecosystems

AbstractClimate and parent material strongly control vegetation structure and function, yet their control over the belowground microbial community is poorly understood. We assessed variation in microbial lipid profiles in undisturbed forest soils (organic and surface mineral horizons) along an altitudinal gradient (700, 1,700, and 2,700 m a.s.l. mean annual temperature of 12–24°C) on two contrasting parent materials (acidic metasedimentary vs. ultrabasic igneous rock) in Mt. Kinabalu, Borneo. Soil organic carbon and nitrogen concentrations were generally higher at higher altitudes and, within a site, at upper soil horizons. Soil pH ranged from 3.9 to 5.3, with higher values for the ultrabasic soils especially at higher altitudes. The major shifts in microbial community structure observed were the decline in the ratio of fungal to bacterial lipid markers both with increasing soil depth and decreasing altitude. The positive correlation between this ratio with soil C and N concentrations suggested a strong substrate control in accord with the literature from mid to high‐latitude ecosystems. Principal component analysis using seven groups of signature lipids suggested a significant altitude by parent material interaction—the significant difference in microbial community structure between the two rock types found at 2,700‐m sites developed on weakly weathered soils diminished with decreasing altitude towards 700‐m sites where soils were strongly weathered. These results are consistent with the hypothesis that parent material effect on soil microbial community (either directly via soil geochemistry or indirectly via floristic composition) is stronger at an earlier stage of ecosystem development.

New distributional records from central-eastern Madagascar and patterns of morphological variation in the endangered shrew tenrec Microgale jobihely (Afrosoricida: Tenrecidae)

Abstract Microgale jobihely (Afrosoricida: Tenrecidae) was described in 2006 based on 12 specimens from the southwestern flank of Tsaratanana Massif in northern Madagascar. This species is considered Endangered by the IUCN. During small mammal surveys conducted in central-eastern Madagascar within the Ambatovy Forest between June 2007 and February 2009, six specimens allocated to M. jobihely were collected. This site is 485 km southeast of the holotype locality and rests on ultrabasic soils associated with nickel and cobalt deposits. Morphological studies of the Ambatovy and Tsaratanana material provide insights into patterns of variation in this taxon. Notable size variation occurs between the northern and southern populations, as well as differences in craniodental morphology. A portion of the Ambatovy site will be cleared as a result of mineral exploitation and even with the discovery of a second population of this taxon, its conservation status remains Endangered.

Substrate, climate, and land use controls over soil N dynamics and N-oxide emissions in Borneo

Nitrogen (N) enrichment of tropical ecosystems is likely to increase with rapid industrial and agricultural development, but the ecological consequences of N additions in these systems are not well understood. We measured soil N- oxide emissions and N transformations in primary rain forest ecosystems at four elevations and across two substrate types on Mt. Kinabalu, Borneo, before and after short-term experimental N additions. We also measured N pools and fluxes across a land use gradient of primary forest, burned secondary forest, and fertilized agriculture. Back- ground soil N20 and NO emissions in primary forest decreased with elevation, and soils derived from sedimentary substrates had larger pools of inorganic N, rates of nitrification, and N-oxide fluxes than ultrabasic soils when there were significant differences between substrate types. N-oxide emissions after N additions and background rates of nitrification were low in all soils derived from ultrabasic substrates compared to sedimentary substrates, even at lowland sites supporting, diverse Dipterocarp forests growing on morphologically similar Oxisols. Rates of potential nitrification were good predictors of N-oxide emissions after N additions. N20 and NO fluxes were largest at low elevations and on sedimentary-derived soils compared to ultrabasic-derived soils, even at the smallest addition of N, 15 kg N ha-1. Because current methods of soil classification do not ex- plicitly characterize a number of soil chemical properties important to nutrient cycling, the use of soil maps to extrapolate biogeochemical processes to the region or globe may be limited in its accuracy and usefulness. In agricultural systems, management practices were more important than substrate type in controlling N-oxide emissions and soil N cycling. N-oxide fluxes from agricultural fields were more than an order of magnitude greater than from primary forests on the same substrate type and at the same elevation. As primary forests are cleared for intensive agriculture, soil N20 and NO emissions are likely to far exceed those from the most N-saturated tropical forest ecosystems. This study highlights the inter-dependence of climate, substrate age, N deposition, and land-use practices determining N cycling and N-oxide emissions in humid tropical regions.

The economic potential of ultrabasic soils in the vicinity of Ranau, Sabah

The economic potential of ultrabasic soils in the vicinity of Ranau, Sabah

A long vegetation history from lowland Irian Jaya, Indonesia

This paper reports the pollen analysis of a 10 m core from a mire at 780 m altitude and 2°S latitude on ultrabasic soils on a northern coastal range of New Guinea. The area is almost undisturbed by humans and the record is believed to cover about 60,000 yr B.P. The results show that montane forest grew around the site continously through the Late Pleistocene with a distinct increases in higher-altitude taxa from 25,000 to 10,500 yr B.P., the time of glacial maxima elsewhere. The invasion of the site by lower-altitude forest, which commenced at 10,500 yr B.P., was reversed after a few hundred years, and was not finally completed until about 7000 yr B.P. The results show that vegetation in the region has been sensitive to climatic change, the Pleistocene ecology being consistent with a temperature change of about 3–4°C. Times of change agree with other tropical areas even though the site climate was probably affected by changing sea levels. However, the tropical forest demonstrates overall long-term stability in which changes in dominance may reflect minor shifts in disturbance and tree longevity. A distinctive record of fine charcoal occurs after 10,900 yr B.P. but not at any level prior to that time. This shows that the forest was continously fire free for a very long time. the charcoal is probably an indication of anthropogenic disturbance which may correlate with the spread of agricultural innovation in lowland New Guinea. An increase in secondary species after 7000 yr B.P. may be a result of minor anthropogenic activity or the result of warmer conditions and shorter tree life in the lower-altitude forests.

Chromium accumulation, transport and toxicity in plants∗

The predominant pathway for human exposure to chromium in non‐occupationally exposed individuals is via food with a daily intake of around 30–100 μgd–1, with vegetables providing a major contribution. Unlike reports of chromium essentiality to man and animals, plants appear not to require chromium in spite of some early reports of a stimulatory growth effect. Most reports on chromium in plants have been concerned with their growth on soils amended with sewage sludge, pF‐ash, tannery waste, or on ultra basic soils, which contain extreme concentrations of the element. Experimental studies with plants grown in hydroponic solution have often been undertaken at unrealistically high concentrations to examine the uptake of chromium in various forms, either as CrIII or CrVI at different pHs. In most cases, reports on chromium in plants deal with element concentrations and plant/soil relationships rather than detailed biochemical and physiological processes. In general, chromium is largely retained in the roots of...

The vegetation of ultrabasic soils on the Isle of Rhum I. Physical environment, plant associations and soil chemistry

Summary Rhum is a cool, windy island which has a high rainfall. Its ultrabasic soils are mildly acid, have exchangeable Mg/Ca quotients of 1.0–1.5, total nickel concentrations up to 2100 µg g− 1, and have a very high proportion of coarse sand particles. Mg/Ca quotients were higher in extracted soil solutions. A TWINSPAN classification of vegetation data from 283 quadrats on ultrabasic and non-ultrabasic soils produced seven interpreted vegetation Groups on the former soils and five on the latter. The Groups fit more or less into Associations or Communities described by Birse (1980, 1984). The vegetation of the more open ‘debris’ has some rare or uncommon species and is unusual amongst British ultrabasic areas in often having Calluna vulgaris and Molinia caerulea even when the total cover values are less than 5%.

The vegetation of ultrabasic soils on the Isle of Rhum II. The causes of the debris

Summary The relationship between the Rhum ultrabasic skeletal soils and their debris vegetation was investigated by plant analyses and field and laboratory experiments. Samples of Agrostis vinealis, Arenaria norvegica ssp norvegica, Calluna vulgaris, Festuca vivipara, Plantago maritima and Racomitrium lanuginosum from these soils usually had low concentrations of potassium and calcium, and high concentrations of sodium, magnesium (and high Mg/Ca quotients), iron and nickel. There were instances of very high iron concentrations (up to 22.4mg g−1 in Plantago maritima), very high Mg/Ca quotients (up to 27.8 in Arenaria novegica spp. norvegica) and high nickel concentrations (up to 0.48mg g−1 in Plantago maritima). A nutrient addition experiment which was set up in 1965 on an exposed barren area had in 1982 over twice as many species as originally recorded and a nearly complete plant cover. Shorter-term work has confirmed that nutrient availability limits the ultrabasic vegetation. An experiment on Agrostis v...

Plant-soil relationships in a New Caledonian serpentine flora

Elemental concentrations were studied in two New Caledonian hyper-accumulators of nickel and in the soils supporting these plants. The nickel content of Hybanthus austrocaledonicus was directly related to the total nickel content of the soil, and this species may therefore be used for biogeochemical prospecting. Nickel was correlated well with other elements of the iron family in non-lateritic ultrabasic soils but not in laterites. Both H. austrocaledonicus and Homalium kanaliense contained adequate amounts of potassium despite very low concentrations in the supporting soils. These low nutrient levels were further aggravated by antagonism to potassium uptake caused by other soil elements. Because of the paucity of relationships between nickel in H. kanaliense and elements in the soil, it is suggested that the high nickel levels in this plant may be controlled by organic constituents in this species. re]19760504