Top Soil Research Articles

In situ bioaccumulation of metals by Prosopis juliflora and its detoxification potential at the metal contaminated sites

Heavy metals emanate from diverse anthropogenic activities and the top soil in the vicinity of these activities acts as an immediate sink and facilitates diffusion of heavy metals into the food chain. In the semi-arid plains of India, Prosopis juliflora is the most common and dominant weed along the motorways and barren lands including industrial environs. This investigation hypothesizes the adaptive nature of Prosopis juliflora in the metal enriched soils and attempts to understand its hyper-accumulating potential of metals besides bioconversion/detoxification capability. Prosopis juliflora samples (root, stem, leaves, and pods) from 100 sites in the environs of anthropogenic activities (vehicular emissions and industrial operations) were analyzed for heavy metal concentrations (Cu, Fe, Cr, Cd, Ni, Pb). Prosopis juliflora accumulate metals at the rate of 0.138 mg/kg/day DW for Copper (Cu), Fe: 0.142 mg/kg/day DW, Cr: 0.114 mg/kg/day DW, Ni: 0.048 mg/kg/day DW, Pb: 0.052 mg/kg/day DW, Cd: 0.009 mg/kg/day DW. Furthermore, X-ray Photoelectron Spectroscopy (XPS) metal oxidation state analysis revealed that in the pods of Prosopis juliflora heavy metals (Fe, Cr, Pb) largely existed in non-toxic form (toxic:non-toxic - 3:6), while in the under canopy soil, metals predominantly existed in toxic form (toxic:non-toxic - 7:2); conclusively XPS results ascertains the heavy metal bioconversion/detoxification potential of the plant. These findings suggest that presence of Prosopis juliflora coppice in the barren landscapes across the transportation corridors and metal based industrial zones may ideally favor phyto-remediation of heavy metals.

Temperature related to the spatial heterogeneity of wetland soil total nitrogen content in a frozen zone

Changes in soil total nitrogen (N) content would affect wetland function and the global N cycle. Determination of spatial heterogeneity controlling factors of wetland soil total N content per unit mass is essential to assess responses of ecosystem N cycle to global change. However, such information is limited in permafrost zones because few soil profiles have been acquired and methods to predict spatial distributions of wetland soil total N content in large areas are inefficient, which increase uncertainty in evaluations of N cycle at national or global scales. To determine the spatial heterogeneity of wetland soil total N content at different soil depths and frozen zones and the factors controlling wetland soil total N content in the frozen zones of Northeast China, the spatial pattern of wetland soil total N content was investigated by using a random forest method that combined field samples with environmental factors. Vertically, wetland soil total N content decreased with increasing soil depth, with the highest content in the top soil layer (0–30 cm). Spatially, wetland soil total N content decreased from northwest to southeast, with relatively high total N content in a continuous permafrost zone and relatively low total N content in a seasonally frozen zone. The overall coefficient of variation of wetland soil total N content in the frozen zones of Northeast was 29.58 %, indicating moderate variation. Land surface temperature, mean annual temperature, and mean annual humidity significantly affected total N content in 0–30 and 30–60 cm soil layers, suggesting that variations in temperature and humidity altered sequestration processes of wetland soil total N content. In the 60–100 cm soil layer, compared with other environmental factors, mean annual humidity, altitude, and mean annual precipitation had the greatest influence on the spatial distribution of wetland soil total N content. The study unravels the spatial pattern of soil total N content in frozen zones of Northeast China and reflects the direct and indirect effects of environmental factors on total N content. This provides a basis for the management and protection of wetland ecosystems.

Enzymatic Stoichiometry Reveals the Metabolic Limitations of Soil Microbes under Nitrogen and Phosphorus Addition in Chinese Fir Plantations.

Increasing nitrogen (N) deposition alters the availability of soil nutrients and is likely to intensify phosphorus (P) limitations, especially in P-limited tropical and subtropical forests. Soil microorganisms play vital roles in carbon (C) and nutrient cycling, but it is unclear whether and how much N and P imbalances affect the soil's microbial metabolism and mechanisms of nutrient limitations. In this study, a 3-year field experiment of N and P addition (control (CK), 100 kg N ha-1 yr-1 (N), 50 kg P ha-1 yr-1 (P), and NP) was set up to analyze the extracellular enzyme activities and stoichiometry characteristics of the top mineral soils in Chinese fir plantations with different stand ages (7, 20, and 33 years old). The results showed that the enzyme activities associated with the acquisition of C (β-1,4-glucosidase (BG) and β-d-cellobiohydrolase (CBH)) and P (acid phosphatases (APs)) in the N treatment were significantly higher than those in the CK treatment. Moreover, vector analysis revealed that both the vector's length and angle increased in stands of all ages, which indicated that N addition aggravated microbial C and P limitations. The P and NP treatments both significantly decreased the activity of AP and the enzymes' N:P ratio, thereby alleviating microbial P limitations, as revealed by the reduction in the vector's angle. Stand age was found to promote all enzymatic activities but had no obvious effects on the limitation of microbial metabolism with or without added nutrients in the soils under Chinese fir. Available N, Olsen-P, and pH were the main drivers of microbial metabolic limitations related to C nutrients. These results provide useful data for understanding the change in soil microbial activity in response to environmental changes, and suggest that P fertilization should be considered for management to improve productivity and C sequestration in Chinese fir plantation in the context of increased deposition of N.

Growth Response of Cocoa Seedlings (Theobroma cacao L.) in several Combinations of Planting Media and Trichoderma sp. as Biological Fertilizer

Indonesia is the third largest cocoa (Theobroma cacao L.) producing country in the world. In 2019 cocoa production in Lampung was 58,852 tons with a plantation area of 79,356 ha, in 2020 it was 58,623 tons with an area of 79,469 ha and in 2021 58,414 tons with an area of 77,174 ha. One of the reasons for this decline in production is plant pest organisms (OPT), namely fruit rot disease caused by the pathogen Pytophthora palmivora. Use of Trichoderma sp. can increase plant resistance and growth and act as a biological controller outside and inside the soil. The research was carried out on the grounds of the Lampung State Polytechnic from August to November 2023. This research aims to determine the effect of planting media and administration of Trichoderma sp. on the growth of cocoa seedlings. The method used was a Randomized Block Design (RAK) with 4 treatments and 4 replications so that there were 16 experimental units. Treatment P0 consisted of: Top Soil (Control), P1 Top Soil + Compost Fertilizer (2:1), P2 Top Soil + Trichoderma sp. (50:1), P3 Top Soil + Compost + Trichoderma sp. (50:25:1). The results of the research on treatments P3, P2 and P1 affected plant height, number of leaves and stem diameter. The P3 treatment showed the best results for the variables plant height 39.50 cm, number of leaves 21.58 and leaf area 37.79 cm2. Treatment P2 showed the best results for the stem diameter variable of 0.66 cm.

Transforming ex-Coal Mining Sites into Sustainable Plantations: A Case Study of Food Natural Sustainability Project in Bomba Group

The Ministry of Agriculture (Kementan) is encouraging efforts to convert former mining land into productive agricultural areas to increase national food production and stocks amidst the global food crisis. Land Reclamation Technology is a necessity to reduce the cost of reclamation of ex-mining land into agricultural land. The method of reclamation of ex-mining land by moving top soil from another place is not recommended because this is a step to solve the problem by creating other new problems. Sustainability Business Model for such rejuvenation projects refer to Collaboration and Community Based and must be prioritize all stakeholders (all parties involved and affected by the activities carried out by the business) rather than the interests of shareholders.

AHP and geospatial technologies for identifying groundwater exploration target regions in Dindigul, southern India

Recent advances in space technology are being widely utilized in resource mapping and management as they provide a high level of accuracy over a short duration and at a lower cost, when compared to traditional methods. Remote sensing and the geographical information system (GIS) play a vital role in collecting and analyzing information used to map resources and earth surface features. For example, anthropogenic activities and climate change affect the natural interaction between the surface and ground water making the monitoring and management of groundwater resources mandatory for future sustainable development. In this study, we attempt to identify the groundwater potential zones in the Dindigul district of Tamil Nadu, India using these emerging technologies. To map regions with groundwater potential, the analytical hierarchical process (AHP) was used to assign weights to all classes in each thematic layer based on groundwater-influencing factors. The sub-features of every parameter were also ranked, using a pairwise comparison method, based on the groundwater-influencing factors and expert knowledge. The parameters selected for the analysis were geology, geomorphology, soil, land-use/land-cover, drainage density, lineament density, slope, rainfall, thickness of top-soil, thickness of fractured zone, thickness of weathered zone, topographic wetness index, roughness and curvature. The weighted overlay analysis method was adopted for all the thematic layers, with technical support from the AHP for assigning weightages. The results were classified into five categories viz., very high, high, moderate, low, and very low potential zones, and used to prepare a groundwater potential map. This map revealed a nuanced distribution of groundwater potential across the district, with varying degrees of potentiality in different regions. Very high potential zones occupy a minimal area (0.07%) but are strategically located in areas characterized by high weathered zone thickness and conducive soil characteristics. High potential zones cover a significant area (22.33%) and are dispersed throughout the district, with specific concentrations in regions featuring highly fractured zones and favorable geological attributes. Moderate potential zones (35.12%) are primarily located in the northeastern part of the study area, while low and very low potential regions cover 19.56% and 22.92% of the study area. The low and very low potential zones appear particularly in hilly terrains, with unfavorable top soil and geological conditions. The validation of the groundwater potential zone (GWPZ) map using the annual average water level data demonstrates a substantial match (60.53%) between the identified groundwater conditions and actual well depths, affirming the reliability and significance of the findings from this study.

An integrated approach to obtain high-precision regional root water uptake maps

Root water uptake (RWU) is exceptionally difficult to determine in situ due to its unique nature of occurring underground. Accurately characterizing the spatial–temporal characteristics of RWU at a regional scale remains a significant challenge, and high-precision regional-scale RWU maps have not yet been reported. In this study, we develop a novel approach that integrates the Google Earth Engine (GEE) platform, mathematical models, and machine learning algorithms to generate high-precision regional maps of maize RWU in China’s primary maize production area. The GEE platform was used to extract essential parameters such as soil properties, leaf area index, and growth period. These variables, along with meteorological data from 122 agricultural meteorological stations, were used to calculate RWU at a point scale using the Hydrus-1D and AquaCrop models. Finally, we utilized Hydrus-calculated point-scale RWU fluxes, along with 31 covariates extracted from the GEE platform, in conjunction with the CatBoost algorithm to develop a machine-learning model for estimating regional-scale RWU. The accuracy of the developed machine-learning model was validated using statistical measures, such asa mean absolute error (0.0299 cm d−1), a root mean squared error (0.0398 cm d−1), and the correlation coefficient (0.9178). The model was then applied to generate high-precision (500 m × 500 m) regional-scale RWU maps from 2015 to 2019. Additionally, our analysis identified several parameters, including TempDew (i.e., 2-m dewpoint temperature), SurfaceSM (i.e., top layer soil moisture), TempMax (i.e., max 2-m air temperature), and Latitude, as key factors influencing regional-scale RWU. This approach provides a robust strategy for accurately generating regional-scale RWU maps, even with limited data. Furthermore, it can be extended to obtain other regional indices, offering valuable insights for various real-world applications.

Coefficient Analysis of the Alluvial Fan Surface Geometry: A Methodological Approach to Applied Geomorphology

The alluvial fan is a depositional geomorphic surface at the foothills. Most of the alluvial fans in tropical regions are highly dynamic under wet climatic conditions and neotectonic environments. The fans of this region are covered with fertile top soils and deep forests. The soils attack people for agriculture in this region. Presently the continuously growing population pressure causes huge deforestation in these alluvial fan areas for cultivation which causes an accelerating rate of natural hazards like flash floods, landslides, and soil erosion that accelerate the dynamic nature of the fan surfaces. The coefficient analysis helps to understand the dynamic nature of the alluvial fan surface and thus helps to identify the hazard-prone area for planning purposes.

Substantial terrestrial carbon emissions from global expansion of impervious surface area

Global impervious surface area (ISA) has more than doubled over the last three decades, but the associated carbon emissions resulting from the depletion of pre-existing land carbon stores remain unknown. Here, we report that the carbon losses from biomass and top soil (0–30 cm) due to global ISA expansion reached 46–75 Tg C per year over 1993–2018, accounting for 3.7–6.0% of the concurrent human land-use change emissions. For the Annex I countries of UNFCCC, our estimated emissions are comparable to the carbon emissions arising from settlement expansion as reported by the national greenhouse gas inventories, providing independent validation of this kind. The contrast between growing emissions in non-Annex I countries and declining ones in Annex I countries over the study period can be explained by an observed emerging pattern of emissions evolution dependent on the economic development stage. Our study has implications for international carbon accounting and climate mitigation as it reveals previously ignored but substantial contributions of ISA expansion to anthropogenic carbon emissions through land-use effects.

ALEM-FEM-BEM coupling for response analysis of pile group in laminated fluid-saturated geomaterials induced by tunnel excavation

This paper proposes a two-stage analytical methodology for predicting the response of pile groups in layered fluid-saturated soils induced by tunnel excavation. The Loganathan analytical approach is adopted for estimating the free-field response induced by tunneling. At the second phase, the solution to the surrounding soil of pile groups is employed as the kernel function based on the analytical layer-element method (ALEM). Subsequently, the analysis of soil-structure interaction is presented using the boundary element method (BEM). The Timoshenko-beam model is utilized to simulate each monopile combined with finite element method (FEM). Finally, the responses of adjacent pile groups are derived by the coordination conditions and coupling of BEM and FEM. Comparisons are made between the presented analytical solutions and existing experimental and numerical results. Parametric analyses are performed to evaluate the influence of soil permeability, material stratification, tunnel-pile distance, tunnel buried depth, and pile slenderness ratio on the mechanical behavior of grouped piles. The results show that the pile group in hard top and soft bottom saturated soils demonstrates better load-bearing capacity than that in soft upper and hard lower soils. Then, with the increment of tunnel-pile distance, the displacement and bending moment are reduced by 22.2 %-50 % and 41.2 %-66.7 %, respectively, and the increased rate of mechanical response over time slows down. Moreover, increasing the burial depth reduces the displacement by 8.6 %-33.3 % and the bending moment by 33.4 %-50 %, respectively, and the locations of peak responses increase from 0.6 times the pile length to 0.8 times the pile length.

Hydrus-1D Model for Simulating Potassium Transport in Rice Crop Irrigated with Alternate Wetting and Drying Practice

ABSTRACT Potassium (K) is one of the essential nutrients that play a crucial role in rice fields; however, its availability, transport, and balance components can be influenced by alternating wetting and drying (AWD) irrigation practice. This study used the Hydrus-1D solute transport model to simulate K transport and balance components in AWD irrigated rice fields. Thirty lysimeter field experiment plots with three different irrigation treatments (No: no soil water stress, MS: mild soil water stress (400 cm), and SS: severe soil water stress (750 cm)) were used for rice cultivation. Daily measurements of soil matric potential head (SMPH) and ponding water depth (PWD) were recorded. Throughout the rice-growing season, leachate water samples from the surface (ponding water) and soil profiles were collected to measure K content. Using the lysimeter field experiment data, the Hydrus-1D model simulated K transport in the AWD rice field. The simulation results indicate that the K distribution predominantly occurred within the top puddled soil layer (0–20 cm) in AWD practice. This suggests that the recommended K fertilizer dose with a 4–5 cm PWD and SMPH of 400 cm optimizes K availability for rice while limiting K leaching loss. The Hydrus-1D model proves to be a valuable management tool, aiding in determining optimal K application rates and ponding water depths for AWD irrigation, ensuring sufficient K nutrients for rice, and controlling K loss for sustainable rice production.

Diversity of Calonectria species from leaves and soils in diseased southern China Eucalyptus plantation

Calonectria leaf blight (CLB) is one of the best-known diseases of Eucalyptus spp., particularly in Asia and South America. Recently, typical symptoms of leaf and shoot blight caused by Calonectria spp. Were observed in a Eucalyptus plantation in the YunNan Province of southwestern China. Isolations were made from diseased leaves and top soil collected below the diseased trees to determine the causal agent of the disease and to consider the distribution characteristics of the Calonectria species. This resulted in 417 isolates, of which 228 were from leaves and 189 were from soil. Based on comparisons of DNA sequences for the act (actin), cmdA (calmodulin), his3 (histone H3), rpb2 (the second largest subunit of RNA polymerase), tef1 (translation elongation factor 1-alpha) and tub2 (β-tubulin) gene regions, as well as morphological characteristics, 11 Calonectria species were identified. These included Calonectria aciculata (0.7 %), Ca. colhounii (1.2 %), Ca. eucalypti (10.6 %) and Ca. honghensis (43.2 %) in the Ca. colhounii species complex, and Ca. aconidialis (15.3 %), Ca. asiatica (9.8 %), Ca. hongkongensis (1.0 %), Ca. ilicicola (6.0 %), Ca. kyotensis (0.5 %), and Ca. yunnanensis (11.3 %) in the Ca. kyotensis species complex. In addition, a novel species, accounting for 0.5 % of the isolates, was discovered and is described here as Ca. dianii sp. nov. in the Ca colhounii species complex. Most (99.1 %) of the isolates collected from the leaves resided in the Ca. colhounii species complex and a majority (95.8 %) of those from the soils were in Ca. kyotensis species complex. These results suggest that Calonectria spp. in the Ca. colhounii species complex infecting leaves might be adapted to that niche and that those in the Ca. kyotensis species complex are better adapted to a soil habitat.

Bacterial community composition and function vary with farmland type and soil depth around a mining area

Heavy metal pollution can have adverse impacts on microorganisms, plants and even human health. To date, the impact of heavy metals on bacteria in farmland has yielded poor attention, and there is a paucity of knowledge on the impact of land type on bacteria in mining area with heavy metal pollution. Around a metal-contaminated mining area, two soil depths in three types of farmlands were selected to explore the composition and function of bacteria and their correlations with the types and contents of heavy metals. The compositions and functions of bacterial communities at the three different agricultural sites were disparate to a certain extent. Some metabolic functions of bacterial community in the paddy field were up-regulated compared with those at other site. These results observed around mining area were different from those previously reported in conventional farmlands. In addition, bacterial community composition in the top soils was relatively complex, while in the deep soils it became more unitary and extracellular functional genes got enriched. Meanwhile, heavy metal pollution may stimulate the enrichment of certain bacteria to protect plants from damage. This finding may aid in understanding the indirect effect of metal contamination on plants and thus putting forward feasible strategies for the remediation of metal-contaminated sites. Main findings of the workThis was the first study to comprehensively explore the influence of heavy metal pollution on the soil bacterial communities and metabolic potentials in different agricultural land types and soil depths around a mining area.

Analisis Penggunaan Tanaman Vetiver terhadap Stabilitas Lereng pada Bendungan Way Sekampung

Problems that occur in the western part of As Way Sekampung have the potential for landslides to occur. Efforts used to handle slope strengthening by planting vetiver plants. The research method used to analyze slopes uses the limit equilibrium method on slip surface sections using the Morgenstren-Price method with the help of Geostudio 2023.1.0 software. SLOPE/W to get the safety factor under normal conditions and under seismic load conditions. By using a seismic load with a return period of 500 years (PE 10% in 50 years) with a Peak Ground Acceleration (PGA) value for the Way Sekampung Dam inundation area of 0,265 g. In vetiver plants, the root depth is simulated according to the top soil depth of 0,0 – 0,1 m. Soil planted with vetiver plants experienced an increase in the value of cohesion (c) by 74,42% and a decrease in the value of the angle of internal friction (φ˚) by 49,40%. The conclusion obtained was that slope stability in normal existing conditions was 4,525 and in normal vetiver plant strengthening conditions the safety factor increased to 4,529. Then, in the existing seismic conditions, the safety factor is 2,624 and in strengthening vetiver plants with seismic loads, the safety factor value increases to 2,626. It can be concluded that vetiver plants are able to strengthen slope conditions.

Amelioration’s Effects on Soil Chemical Properties in Maize Cultivation in Dryland Aceh, Indonesia

Background: Amelioration is the technique of adding amendments to sub-optimal drylands to improve their chemical quality. The effectiveness of this amendment depends on the type and dosage of the amendment. Methods: This pot experiment was carried out using a randomized block design (RBD) in 3 replications. Treatment of amendment materials (A) which consists of 8 (eight) treatments, namely: A0 (no amendment); A1 (biochar 20 t ha-1); A2 (compost 20 t ha-1); A3 (CaCO3 4 t ha-1); A4 (SP-36 fertilizer 4 t ha-1); A5 (biochar 10 t ha-1 + CaCO3 4 t ha-1); A6 (compost 10 t ha-1 + CaCO3 4 t ha-1); and A7 (biochar 10 t ha-1 + compost 10 t ha-1). The top soils (0-20 cm) were used in the experiment taken from three soil orders of sub-optimal dryland of Aceh Besar Regency, Aceh (Indonesia), including Andisols, Inceptisols and Ultisols. Result: Providing amendments affects several soil chemical parameters in the drylands of Aceh and this effect depends on the type of ameliorant material and the dose applied as well as the soil order. By applying amendments, soils with a slightly acidic pH could turn slightly alkaline, resulting in an increase in available P, K and cation exchange capacity (CEC) of dryland soils.

Pengaruh Bokashi Limbah Kulit Kopi pada Bibit Pepaya (Caraca Papaya L.) Calina

This study aimed to determine the effect of the proportion of coffee peel bokashi in the planting medium on the growth of papaya plant seedlings (Carica papaya L.) cv Calina. The research was conducted at the Faculty of Agriculture Screenhouse on Jalan Perjuangan, Cirebon City, at an altitude of 5 m above sea level. The research was conducted from May 2022 to June 2022. The experimental method used with a completely randomized design. The treatment consisted of 4 proportions of bokashi in the planting media, each of which was repeated 6 times so that there were 24 experimental units. Each experimental unit consisted of 10 polybags. The total papaya plant seeds used were 240 seeds. The treatments studied were: K0 = top soil, K1 = 250 g bokashi + 1 kg soil, K2 = 500 g bokashi + 1 kg soil, and K3 = 750 g bokashi + 1 kg soil. The results showed that the proportion of coffee peel waste bokashi significantly affected the growth of papaya plants. Using 500 g coffee skin waste bokashi in 1 kg of soil had the best effect on plant height, stem diameter, plant growth rate, number of leaves, root volume, root length, root ratio, and net assimilation rate. Keywords: coffee peel, bokashi, papaya

Decrease in soil test phosphorus levels under omitted phosphorus fertilizer application

AbstractMany European cropped soils have high soil test P (STP) values in the top soil because of P accumulation over many years of fertilizer application. This should allow to save P fertilizer applications for some years without STP values decreasing to a level that might negatively impact crop yield. However, the way STP develops under omitted P fertilizer application is not well understood. We examined STP development under omitted P fertilizer application for timeframes between 7 and 46 years on 96 unfertilized treatments (P0 treatments) of 43 European long‐term P field experiments, using five different STP methods. For comparability, values obtained by different STP methods were converted to Olsen‐P concentrations. We fitted exponential decay curves to Olsen‐P data of each P0 treatment defined by initial Olsen‐P values (Olsen‐Pi), rates of decrease (k) and asymptotes (A), reflecting minimum obtainable STP. Subsequently, we analysed whether the variables most commonly recorded in experiments, are sufficient to explain the variation in model parameters, these variables being P export, clay content, Corg and pH as well as average annual temperature and precipitation. We found that out of our predictor variables, soil clay content, precipitation and temperature were showing the most prominent effects on the parameters Olsen‐Pi, A or k. However, the amount of variation explained by the considered variables was too low to potentially facilitate a prediction of STP decrease, and various P0 treatments showed no clear Olsen‐P decrease or unexpectedly high asymptotes. This hints at a strong influence of the P sorption capacity of the soil with often high potential for replenishment from less available P pools. In connection with P introduction from the subsoil or possibly from surrounding plots, the extension of timeframes of omitted P fertilizer application without reaching critical STP values for crop production, might be explainable. Corresponding effects could not be analysed because of lack of data for most P0 treatments, calling for the additional determination of, for example, the maximum P sorption capacity, total P and subsoil P in future experiments.

Impact of Metals Scrap Yard on the Presence of some Heavy Metals Concentration within Gombe Metropolis, Gombe State, Nigeria, using Atomic Absorption Spectrometry

The Metal scrap yards play a crucial role in the recycling and reuse of metals, contributing significantly to the economy and conservation of natural resources. However, the processing and storage of metal scraps can lead to the release of heavy metals such as lead, chromium and cadmium, into the environment. The presence of heavy metals in metal scrap yards poses a significant risk to nearby communities, workers and the environment, also causing air and water pollution, soil contamination, and health problem. Study of impact of metals scrap yard on the presence some of some heavy metals in soil samples was done using Atomic Absorption Spectrometer (AAS). Top soil sample were collected from eight metals scrap yards and their corresponding control areas. One gram (1 g) each of the soil samples was digested and then heated slowly and steadily, the solution appears colorless. The samples were allowed to cool and ready for analysis. The result obtained was, the mean elemental concentration element was of the order ofMn (41.022±41.202)> Cu (4.416±4.274) >Pb (2.685±1.399) > Mg (0.500±10.122) > Cr (0.460±0.187) > Cd (0.125±0.027) > Co (0.04±0.000)> Ni (0.000±0.000). The comparison of the elemental concentration of the heavy metals of (Mn, Mg, Cu, Pd, Cr, Cd, Co and Ni) in the study area ware shows the metal scrap yard has impact in the presence of heavy metals in soil. In addition, the Contamination factor (CF), and Pollution load index (PLI) of each trace element in soil of the study area and their respective control area were all < 1 which implies that they all have low contamination factors, less polluted and low contaminated.

NIGHT-FLYING BEETLES, ADORETUS COMPRESSUS – PESTS OF OIL PALM

Adoretus compressus are small night-flying beetles, and also known as cockchafer beetles. A. compressus beetles are about 10-15 mm long, brown in colour and elongate and oval shaped. Adults usually eat by chewing and forming small holes in the foliage. The larvae or grubs live in the soil, generally under grass and almost exclusively feeding on plant refuse or decaying vegetable matters of the top soil. Life history of A. compressus is not well known and the life cycle of the insect is roughly complete in three months. A. compressus is polyphagous and feeds on leaves of many species of plants including several plantation based crops of tea, coconut, cocoa, rubber and oil palm. It is the most common insect pest in oil palm nurseries. Occasional outbreaks cause serious defoliation in immature plantings. During serious outbreaks, large number of Adoretus beetles can cause 80 to nearly 100 per cent defoliation of newly planted seedlings within two weeks. Almost all the fronds become badly damaged and skeletonised; and finally total drying of leaves occurs. Yield recording started when fruit bunches production commenced for a period of 27 months. Even though the affected palms recovered after effective chemical control, immature palms with severe damage (more than 50% defoliation) recorded 27 per cent reduction in fresh fruit bunch (FFB) yield and 18 per cent reduction in bunch number. Various aspects of management and control are discussed. In dealing with occasional outbreaks, spraying of insecticides like triclorfon, carbaryl, carbosulfan and cypermethrin at intervals of 7 to 14 days is effective. In southern Thailand, spraying of carbaryl 85 per cent wettable powder (WP) 60 g per 20 litres water + application of carbosulfan 5 per cent granules (G) at 200 g per palm gave 100 per cent effectiveness after three rounds of treatments at weekly intervals. Keywords: Adoretus compressus, cockchafer beetles, night flying beetles, leaf-eating pest, oil palm, control.

Effects of legacy mining on mercury concentrations in conifer needles and mushrooms in northern Palatinate, Germany

Due to integrated pollution prevention and control measures and the reduced burning of coal, air concentrations of mercury (Hg0) are currently levelling off. In the future, however, evasion from land surfaces will probably reverse this trend. Reasons are the rising temperatures and the loss of forest cover caused by calamities, droughts, storms and wildfires. Plant leaves constitute an important matrix for the accumulation of gaseous mercury and uptake and re-volatilisation by plants depends on the species, the vitality and the age and morphology of leaf organs. It has been shown that older conifer needles show higher concentrations than young needles and Hg accumulation is increasing throughout the season.In present study, we collected branches from Norway Spruce (Picea abies) in a former cinnabar mining region in Northern Palatinate, where artisanal and small-scale mining left innumerable waste dumps. While mining, smelting and processing of the ores were terminated during WWII, high total mercury concentrations remained in the top soils locally, with presumably only small fractions being plant available. In the lab, up to seven needle age classes were analysed. 1000 needle weights increased with age and as expected, also the Hg concentrations were elevated in the older needles. Needle concentrations were higher than those reported from other national biomonitoring programs confirming the regional imprint from legacy mercury. To complement our biomonitoring study, we collected edible mushrooms in former mining areas. Hg concentrations in most samples exceeded the EU maximum residue levels (MRL), while only a few broke the existing cadmium and lead limits. Tolerable weekly intake (TWI) for inorganic mercury would be surpassed with the consumption of a small portion of mushrooms. Further studies should be performed on the outgassing of Hg from mine wastes and the incorporation of Hg in the local food web, including its methylation and biomagnification.