Values Of Organic Matter Research Articles

Changes in Soil Chemical Properties of Rice Paddy, Upland Field, and Greenhouse in Incheon from 2015 to 2019

This study was performed with the monitoring data of soil chemical properties of rice paddy, upland field and greenhouse soils in Ganghwa, Incheon metropolitan city from 2015 to 2019. Soil pH values tended to increase gradually in three soils, but there was no significant change in that of greenhouse soil. The concentration of organic matter (OM) and available phosphate (Av. P2O5) have fluctuated from 2015 to 2019, showing significant differences. In 2019, the average value of OM and Av. P2O5 were distributed within the appropriate level suggested by Rural Development Administration. In rice paddy field, the available silicate (SiO2) were found to be proper within the standard concentration every year. The contents of exchangeable cations were higher than the proper standard, showing significant differences among the years, except greenhouse soil. The mean concentration of EC for five years in upland and greenhouse soils were 2.5 and 5.9 dS m-1 above the proper standard. The optimal frequencies of pH were 46.8% and 47.1% at rice paddy and upland soil, but the excessive frequency ratio of pH was 48.5% at greenhouse soil in 2019. The exchangeable cations seemed to be seriously disproportionate exceeding the optimal level by 95%. In Pearson correlation matrix, the value of exchangeable Ca had a significantly positive correlation with exchangeable Mg content at upland and greenhouse soils. By principal component analysis, the exchangeable K, Mg and OM could distinguish between greenhouse and other soils on the first principal component and the pH and Av. P2O5 could differentiate between rice paddy and upland soils on the second principal component. Scatter plot of chemical properties investigated from rice paddy (P), upland (U) field and greenhouse (F) soils from 2015 to 2019.

Changes in the Impacts of Topographic Factors, Soil Texture, and Cropping Systems on Topsoil Chemical Properties in the Mountainous Areas of the Subtropical Monsoon Region from 2007 to 2017: A Case Study in Hefeng, China.

Understanding the spatial pattern of soil chemical properties (SCPs) together with topological factors and soil management practices is essential for land management. This study examines the spatial changes in soil chemical properties and their impact on China’s subtropical mountainous areas. In 2007 and 2017, 290 and 200 soil samples, respectively, were collected in Hefeng County, a mountainous county in central China. We used descriptive statistics and geostatistical methods, including ANOVA, semivariance, Moran’s I, and fractal dimensions, to analyze the characteristics and spatial autocorrelation changes in soil organic matter (OM), available phosphorus (AP), available potassium (AK), and pH value from 2007 to 2017. We explored the relationship between each SCP and the relationship between SCPs with topographic parameters, soil texture, and cropping systems. The results show that the mean value of soil OM, AP, AK, and pH in Hefeng increased from 2007 to 2017. The spatial variation and spatial dependency of each SCP in 2007, excluding AP and AK in 2007, were higher than in 2017. The soil in areas with high topographic relief, profile curvature, and planform curvature had less AP, AK, and pH. Soil at higher elevation had lower OM (r = −0.197, p < 0.01; r = −0.334, p < 0.01) and AP (r = −0.043, p < 0.05; r = −0.121, p < 0.05) and higher AK (r = −0.305, p < 0.01; r = 0.408, p < 0.01) in 2007 and 2017. Soil OM and AK in 2007 were significantly (p < 0.05) correlated with soil texture (p < 0.05). In contrast, oil AP and soil pH in 2007 and all SCPs in 2017 were poorly correlated with soil texture. The cropping systems played an important role in affecting all SCPs in 2007 (p < 0.01), while they only significantly affected AK in 2017 (p < 0.05). Our findings demonstrate that both topological factors, that is, the changes in cropping management and the changes in acid rain, impact soil chemical properties. The local government should place more focus on reducing soil acid amounts, soil AP content, and soil erosion by improving water conservancy facilities.

Caracterização de solos por espectroscopia no infravermelho próximo e análise de componentes principa

This research aimed to use principal component analysis (PCA) as an exploratory method for spectral data of soil absorbance from the Baturité Massif and Central Hinterland (Ceará State, Brazil) to verify the potential of the technique in soil characterization. We analyzed 46 soil samples from different areas (native and cultivated). Each sample was analyzed in two particle sizes: 2 and 0.2 mm. We obtained spectral data by near-infrared spectroscopy (NIR), selecting the 1,360–2,260 nm range (2,376 variables). We evaluated three data pretreatment methods: multiplicative scatter correction (MSC), first derivative, and second derivative of the Savitzky-Golay filter. The absorption bands observed were: 1,414 nm (C–H stretching and deformation combination), 1,450 nm (O–H associated with the carbon chain), 1,780 nm (second overtone of C–H), 1,928 nm (O–H associated with molecular water), and 2,208 nm (C–H stretch and C=O combination). The best pretreatment was verified using only the multiplicative scatter correction (MSC). Two principal components explained 98% of the data variability, being the first principal component (PC1) related to the characteristic band of moisture, with negative values in the 1,928 nm region, while the second principal component (PC2) was related to the total organic matter (OM) originating from the C–H, C=O, and N–H bonds, wavelength region 1,414 nm. The PCA allowed characterizing the samples in terms of moisture and OM contents, with emphasis on soils under irrigated agroforestry system with higher values of moisture and OM, while the soil in degradation process presented lower values for these attributes. The NIR spectroscopy, associated with data processing methods (PCA and MSC), allows identifying changes in soil attributes, such as moisture and OM.

Digestibility of Local Feed Ingredients in Tilapia Oreochromis niloticus Juveniles, Determined on Faeces Collected by Siphoning or Stripping

Eight locally available protein source ingredients in Tanzania were selected for assessment of apparent digestibility (AD) in tilapia Oreochromis niloticus, using faeces samples collected by siphoning or stripping. The selected protein source ingredients were Lake Victoria sardines (FM), brewers spent yeast (BSY), moringa leaves (ML), freshwater shrimp (FSH), marine shrimp (MSH), cattle blood (CB), duckweed (DW) and fish frames (FF). The AD (%) of dry matter (DM), organic matter (OM) and crude protein (CP) was unaffected (p &gt; 0.782–0.901) by the faeces collection method (i.e., siphoning or stripping), with correlation coefficient (r) of 0.98, 0.99 and 0.93 between AD values for DM, OM and CP, respectively, following siphoning and stripping. The AD (%) of DM, OM, CP and gross energy (GE) in the test ingredients differed (p &lt; 0.0001). The AD (%) of DM and OM was lowest in BSY and DW, followed in increasing order by ML, MSH, FF, FSH and CB. In general, the AD (%) of CP was high (&gt;76%), but with a low value (46%) for DW. The AD (%) of GE was closely correlated (r = 0.96) with the AD of OM. In conclusion, FSH, MSH, CB, FF, BSY and ML have acceptable protein digestibility to be used in tilapia diet formulation.

Assessment of physiochemical properties and concentration of heavy metals in agricultural soils fertilized with chemical fertilizers

The present study aim to assess the effect of phosphate and urea fertilizers on the physicochemical properties, pH and electrical conductivity (EC) of the soil. The effect of these fertilizers on cation exchange capacity (CEC), organic matter (OM), and the possibility of contamination with heavy metals (HM) (Cr, Cu, Cd, Mn, Zn, Ni, Fe, and Pb) were studied on the soils of Alshati agricultural project at different seasons after forty years of fertilization. Uncultivated soil samples were also analyzed for comparison and considered as reference. Mean values of soil pH, EC, CEC, and OM ranged between 6.88-7.32, 0.14–0.26 μS/cm, 2.95–4.19 Cmol/kg and 0.49–0.53%, respectively, in all seasons. Concentrations of HMs were 9.50–38.38, 0.0–2.05, 0.0–0.47, 0.0–29.81, 0.0–13.85, 2.83–25.95 and 104–512.20 mg/kg respectively, for Cr, Cu, Cd, Mn, Zn, Ni and Fe. The concentrations of the HMs in the soil were found to be vary significantly with the seasons (winter, spring, summer, and autumn). However, no traces of Pb was found in the soil samples. The result showed a significant correlation between, pH, EC, CEC, OM and HM content of the soil. The geochemical index of contamination shows that there was no contamination with Cu, Cd, Zn, Pb, Cr, Mn, Ni, and Fe.

Effect of enzyme supplementation and extruding process on the digestibility of nutrients and phenolic acids of defatted rice bran based diets in ileal-cannulated growing pigs

To improve the efficiency of nutrient utilization in defatted rice bran (DRB) used as animal feed ingredient, the effects of enzyme supplementation and extruding process on the coefficient of apparent ileal digestibility (CAID) and apparent total tract digestibility (CATTD) of nutrients and nutraceutical phenolic acids were evaluated using growing pigs (initial body weight = 18 ± 1.2 Kg) permanently fitted with ileal T-cannula. The extruded DRB ingredient (EDRB) was prepared by extruding the DRB ingredient at 130–135 °C using a single-screw extruder. The enzyme preparation contained cellulase, xylanase, phytase, and ferulic acid esterase. Eight cannulated pigs were allocated according to a 4 × 4 double Latin square arrangement. In each period, 1 of 4 tested diets, i.e., DRB basal diet, EDRB basal diet, and their enzyme added counterparts were randomly distributed to 2 pigs (1 pig form each square). The feces were sampled on the 6th and 7th day, and the ileal digesta were collected on the 8th, 9th and 10th day in each period. The results shown that pigs fed EDRB containing diets exhibited higher CAID values of dry matter (DM), organic matter (OM), gross energy (GE), and ether extract (EE) (P <0.001), and CATTD values of DM, OM, GE, crude protein (CP) and EE (P <0.002) comparing with that of DRB containing items. The CATTD values of most NSP fractions and their constituent residues in EDRB diets were positively affected by the extruding process; however, only the CAID values of insoluble arabinose and xylose were increased (P < 0.05). Enzyme inclusion improved the CAID of DM, OM, GE, ash, Ca, total phosphorus (TP) and phytate phosphorus (PP, P <0.05), and the CATTD of ash, Ca, TP, PP, and Mg (P <0.05). The added enzyme increased the digestion of NSP fractions in the foregut of pigs whereas the effect was not obvious in the large intestine of pigs except for insoluble arabinose. The enzyme addition did not show any effect on the CAID and CATTD of CP, and the CAID of amino acids in the rice bran containing diets. On the contrary, the CAID of amino acids were decreased and the CATTD of CP was increased by the extruding process. To sum up, the extruding temperature adopted in this study (130–135 °C) was too high for DRB processing with the aim of improving the efficiency of amino acids utilization, while it was helpful to improve the digestion of most of gross nutrients and NSP fractions over the whole digestive tract of pigs.

The Effect of Lactobacillus plantarum Addition and Fermentation Periods on Nutritive Value Dwarf Elephant Grass (Pennisetum purpureum cv Mott) Silage

This research aimed to examine the effect of different Lactobacillus plantarum addition and fermentation periods on its physical quality, pH, nutritive value ( dry matter (DM), organic matter (OM), crude protein (CP), crude fiber (CF), extract ether (EE)). This research also to find out the best treatments of dwarf elephant grass silage by Lactobacillus plantarum addition with different fermentation periods. Completely Randomized Factorial Design was used in this experiment, with two factor ie. Lactobacillus plantarum inclusion (0, 0.3; 0.6; 0.9 %) and fermentation periods (0, 7, 14, 21 days). Each treatment was replicated three times. Addition 6 % molasses of fresh weight grass was employed in all the treatment. The result indicated that different of Lactobacillus plantarum addition, fermentation periods and their interaction were highly significant effect on pH, OM, CF and EE value (p<0.01). Interaction of two factors also highly significant influence to DM and CP content of dwarf elephant grass silage. Lactobacillus plantarum addition factor has highly significant effect on CP content and fermentation period was a significant effect on CP value of dwarf elephant grass silage. Physical quality of dwarf elephant grass with various Lactobacillus plantarum addition and fermentation periods shown a good quality of silage with fresh and acidic odor, good texture, a little bit browny color, and no fungi. Average pH of silage was around 3.90 – 4.30 after incubation 7 – 21 days. Average of nutritive value dwarf elephant grass silage were 11.55 – 13.15 % DM, 81.13-82.32 % OM, 10.48 – 12.00 % CP, 22.31 – 25.27 % CF and 1.21 – 2.98% EE. It can be concluded that Lactobacillus plantarum addition can faster ensilage fermentation and the best silage was on treatment 0.6 % Lactobacillus plantarum addition and 7 days fermentation periods.

Input of terrestrial organic matter linked to deglaciation increased mercury transport to the Svalbard fjords

Deglaciation has accelerated the transport of minerals as well as modern and ancient organic matter from land to fjord sediments in Spitsbergen, Svalbard, in the European Arctic Ocean. Consequently, such sediments may contain significant levels of total mercury (THg) bound to terrestrial organic matter. The present study compared THg contents in surface sediments from three fjord settings in Spitsbergen: Hornsund in the southern Spitsbergen, which has high annual volume of loss glacier and receives sediment from multiple tidewater glaciers, Dicksonfjorden in the central Spitsbergen, which receives sediment from glacifluvial rivers, and Wijdefjorden in the northern Spitsbergen, which receive sediments from a mixture of tidewater glaciers and glacifluvial rivers. Our results showed that the THg (52 ± 15 ng g−1) bound to organic matter (OM) was the highest in the Hornsund surface sediments, where the glacier loss (0.44 km3 yr−1) and organic carbon accumulation rates (9.3 ~ 49.4 g m−2 yr−1) were elevated compared to other fjords. Furthermore, the δ13C (–27 ~ –24‰) and δ34S values (–10 ~ 15‰) of OM indicated that most of OM were originated from terrestrial sources. Thus, the temperature-driven glacial melting could release more OM originating from the meltwater or terrestrial materials, which are available for THg binding in the European Arctic fjord ecosystems.

Geochemical variations across the Jurassic/Cretaceous boundary in central Mexico. Insights for correlation with Tethyan areas

A multiproxy study of a 29 m-thick carbonate succession in the Apulco area, Puebla State in central Mexico including pyrite framboids, δ13Ccarb, δ18Ocarb, Total Inorganic Carbon (TIC), Total Organic Carbon (TOC) and Organic Matter (OM), reveals minor geochemical changes across the Jurassic/Cretaceous boundary. Anoxic bottom conditions during the Tithonian were registered by high values of TOC and OM, and low values of δ13Ccarb and TIC. Near the Jurassic/Cretaceous boundary, signatures of all measured proxies changed drastically due to processes related with the organic matter preservation in the basin. These changes can be associated with the late Tithonian sea level drop and paleoclimatic variations passing from dry to semi-arid conditions. Otherwise, on late early to late Berriasian facies, values of all proxies tend to the stabilization indicating more oxygenated bottom conditions. The δ13Ccarb goes to positive values while δ18Ocarb and TIC remain constant, the organic matter and total organic carbon decrease to the lowest values. The geochemical behavior of the Apulco section is similar to those reported from other Tethyan sections as Brodno and DSDP 534A and can be preliminary correlated by its chemostratigraphic signal. Additionally, a central age of 141.65 Ma (87Sr/86Sr) in the very base of the calpionellid Elliptica Subzone strengthens the calpionellid biostratigraphic framework for Mexican sections.

Isotope alteration caused by changes in biochemical composition of sedimentary organic matter

Stable carbon (C) and nitrogen (N) isotope ratios of sedimentary organic matter (OM) can reflect the biogeochemical history of aquatic ecosystems. However, diagenetic processes in sediments may alter isotope records of OM via microbial activity and preferential degradation of isotopically distinct organic components. This study investigated the isotope alteration caused by preferential degradation in surface sediments sampled from a eutrophic reservoir in Germany. Sediments were treated sequentially with hot water extraction, hydrochloric acid hydrolysis, hydrogen peroxide oxidation and di-sodium peroxodisulfate oxidation to chemically simulate preferential degradation pathways of sedimentary OM. Residue and extracts from each extraction step were analyzed using elemental analyzer-isotope ratio mass spectrometry and solid-state 13C nuclear magnetic resonance spectroscopy. Our results show that stable C and N isotope ratios reacted differently to changes in the biochemical composition of sedimentary OM. Preferential degradation of proteins and carbohydrates resulted in a 1.2‰ depletion of 13C, while the isotope composition of 15N remained nearly the same. Sedimentary δ15N values were notably altered when lignins and lipids were oxidized from residual sediments. Throughout the sequential fractionation procedure, δ13C was linearly correlated with the C:N of residual sediments. This finding demonstrates that changes in biochemical composition caused by preferential degradation altered δ13C values of sedimentary OM, while this trend was not observed for δ15N values. Our study identifies the influence of preferential degradation on stable C isotope ratios and provide additional insight into the isotope alteration caused by post-depositional processes.

Climate and land use as key factors of the stability of organic matter in soils

Stocks of organic carbon in the soils and its resistance to biodegradation depend on a combination of external and internal determinants which control not only the decomposition, but also the stabilization of organic matter (OM). Soil OM stability was evaluated: 1) by specific mineralization rate (SpMinR) for the forest ecosystems located in various climatic zones of Eurasia (temperate, Mediterranean, and tropical) and 2) by the biological stability index (IBS), determined for the main soil types of the European part of Russia under natural vegetation and agricultural crops. It is shown that the key factors determining the stability of OM of substances in soils are the climate and type of vegetation (land use). Thus, a close negative correlations between the SpMinR values and the annual precipitation and the average annual air temperature were found in the soils of the Eurasian transect. It was revealed that the share of stable and biologically conservative OM and IBS values in the soils under agricultural crops were significantly higher than in the soils of natural cenoses.

Co-vermicomposting of Wastewater Treatment Plant Sludge and Yard Waste: Investigation of Operation Parameters

Million tons of domestic wastewater treatment plant sludge is produced in each year. Since it increases the volume of the landfill area, the treatment of sludge with vermicomposting is an attractive approach. Vermicomposting of domestic wastewater treatment plant sludge with yard waste was carried out using Eisenia Fetida for 60 days. The effects of Bio-One™ (liquid microbial fertilizer), additives (different mature vermicomposts), recirculation and ventilation on decomposition rate of composting were investigated for composting mixtures. Temperature, moisture content (MC), organic matter (OM), pH, electrical conductivity (EC), total carbon (TOC) and total kjeldahl nitrogen (TKN) were monitored during the composting process. In addition, phototoxicity level and worm number changes of the mixtures were determined. C/N and OM value decreases ranged between 27.56–63.77% and 15.15–43.12%, respectively. It was concluded that vermicomposting process was faster than traditional composting process in terms of decomposition of organic matter. The result C/N ratio was more suitable to use it as soil remedial material in vermicomposting process. It has been shown that Bio-One™ addition has a positive effect on the acceleration of the process. It has been found that the process of recirculation some of the leachate formed during the vermicomposting process is an advantageous. It has been determined that mature vermicompost addition is an effective method. The final worm numbers were higher (except ventilation conditions) than the initial. The positive results of the plant growth tests on the final products in all cases may indicate that the products will not cause any toxic effect in the use as soil conditioning material.

Organics preserved in anhydrous interplanetary dust particles: Pristine or not?

AbstractThe chondritic‐porous subset of interplanetary dust particles (CP‐IDPs) are thought to have a cometary origin. Since the CP‐IDPs are anhydrous and unaltered by aqueous processes that are common to chondritic organic matter (OM), they represent the most pristine material of the solar system. However, the study of IDP OM might be hindered by their further alteration by flash heating during atmospheric entry, and we have limited understanding on how short‐term heating influences their organic content. In order to investigate this problem, five CP‐IDPs were studied for their OM contents, distributions, and isotopic compositions at the submicro‐ to nanoscale levels. The OM contained in the IDPs in this study spans the spectrum from primitive OM to that which has been significantly processed by heat. Similarities in the Raman D bands of the meteoritic and IDP OMs indicate that the overall gain in the sizes of crystalline domains in response to heating is similar. However, the Raman ΓG values of the OM in all of the five IDPs clearly deviate from those of chondritic OM that had been processed during a prolonged episode of parent body heating. Such disparity suggests that the nonaromatic contents of the OM are different. Short duration heating further increases the H/C ratio and reduces the δ13C and δD values of the IDP OM. Our findings suggest that IDP OM contains a significant proportion of disordered C with low H content, such as sp2 olefinic C=C, sp3 C–C, and/or carbonyl contents as bridging material.

Climate and Land Use as Key Factors of the Stability of Organic Matter in Soils.

Stocks and biodegradation resistance of organic carbon in soils depend on the combination of external and internal determinants, which control not only the decomposition, but also the stabilization of organic matter (OM). The soil OM stability has been evaluated by (1) specific mineralization rate (SpMinR) for the forest ecosystems located in various climatic zones of Eurasia (temperate, Mediterranean, and tropical) and (2) biological stability index (IBS) determined for the main soil types of European Russia under natural vegetation and agricultural crops. It has been shown that the climate and vegetation type (land use) are the key factors determining the OM stability in soils. For example, close negative correlations of the SpMinR values with the annual precipitation and the mean annual air temperature have been found in soils of the Eurasian transect. It has been revealed that the portion of stable and biologically conserved OM and IBS values in soils under agricultural crops are significantly higher than in soils of natural cenoses.

Changes in Chemical Properties of Greenhouse Soils Collected from Ganghwa

The chemical properties of greenhouse soils in Ganghwa were investigated every year from 2014 to 2018 in order to manage soil fertility and increase crop yield. In 2018, the average concentrations of chemical properties from greenhouse soils were analyzed: 6.4 for pH, 6.72 dS m-1 for EC (electrical conductivity), 23 g kg-1 for OM (amount of organic matter), 187 mg kg-1 for P2O5 (available phosphate), 1.89, 12.09, 4.84 cmolc kg-1 for exchangeable potassium (K), calcium (Ca), magnesium (Mg), respectively. There were no significant changes in the contents of pH and OM from 2014 to 2018. However, the concentration of EC was 3.7 times higher than that of the proper standard recommended by Rural Development Administration in 2018. Further, the excessive frequency ratio about exchangeable cations were 60.6% for K, 93.9% for Ca and 95.9% for Mg based on the recommendation and the contents of exchangeable cations had a tendency to increase according to the years. The frequency ratio of P2O5 which is insufficient in comparison with the standard was 83.8% and the concentration of P2O5 was 1.9 times lower than that of the recommendation in 2018. The P2O5 content had tended to decrease with years. The OM values of cucumber and tomato were higher than those of pepper and water melon, whereas the contents of P2O5 were also insufficient in all crops. Based on principal component analysis, EC was significantly correlated with exchangeable cations, K, Ca and Mg from greenhouse soils in Ganghwa. In order to promote soil fertility of greenhouse in Ganghwa, it is necessary to apply phosphate fertilizer and manage soil nutrients based on the soil tests and analyses. Pearson correlation coefficient matrix comparing paired chemical properties of greenhouse soils in Ganghwa.

Natural and experimental structural evolution of dispersed organic matter in mudstones: The Shimanto accretionary complex, southwest Japan

AbstractStructural changes induced by thermal maturation of dispersed organic matter (OM) in the Shimanto accretionary complex, southwest Japan, were investigated using micro‐Fourier‐transform infrared spectroscopy and micro‐Raman spectroscopy. Natural dispersed OM exhibits systematic structural changes inferred from D1‐ and G‐band FWHM values, Raman band separation (RBS), and intensity ratios of the D1‐ and G‐bands (ID1/IG ratio) from diagenetic zone to anchizone (IC values: 0.75–0.30). Infrared spectra indicate a loss of aliphatic CH x, aromatic CH x, and oxygen‐containing structures as temperature increases. These changes are consistent with discontinuities in thermal structures bounded by out‐of‐sequence thrusts. Kinetic pyrolysis experiments indicate that the ID1/IG ratio of synthesized OM has a power law relationship with heat treatment time. Kinetic models of temperature dependence were fitted using the ID1/IG ratio, and an effective activation energy of 106 ±17 kJ/mol was estimated using an Arrhenius equation. The activation energies estimated by power law rate and Avrami models have a least‐square correlation coefficient of 0.93, indicating the temperature dependence of carbonization. The estimated effective activation energy is consistent with that of coal, lignin, cellulose, and hemicellulose during thermal degradation. On the other hand, RBS, and D1‐ and G‐band FWHM values of OM display more complex changes with increasing heating temperature and time, and it is difficult to constrain rate parameters during pyrolysis experiments. Our data indicate that the ID1/IG ratio is controlled by a simple thermally activated process, whereas RBS and D1‐ and G‐band FWHM values can be affected by lithostatic pressure, fluid activity, hydrogen index, and host lithology, as well as temperature. Structural evolution of dispersed OM in mudstones differs between natural and anhydrous closed experimental systems. Natural carbonization based on micro‐Raman spectroscopy should be applied for a limited indicator of thermal maturation, especially for dispersed OM in diagenetic zone.

Streptomyces pactum combined with manure compost alters soil fertility and enzymatic activities, enhancing phytoextraction of potentially toxic metals (PTMs) in a smelter-contaminated soil

The effect of manure compost alone and combined with Streptomyces pactum (Act12) applied in the smelter-contaminated soil was investigated. The soil fertility, enzymatic activities, potentially toxic metals (PTMs) solubility, and phytoremediation efficiency of potherb mustard (Brassica juncea, Coss.) were assessed. Results showed that the application of compost reduced the soil pH, while significantly increased the soil electrical conductivity (EC) (7.0 folds), available phosphorus (AP) (10.8 folds), available potassium (AK) (2.81 folds), dissolved organic carbon (DOC) (5.22 folds), organic matter (OM) (4.93 folds), together with soil enzymatic activities viz. urease (UR) (4.39 folds), dehydrogenase (DEH) (45.0 folds) and alkaline phosphatase (ALP) (123.9 folds) in comparison with control. The inoculation of Act12 increased AP, AK, DOC, OM and UR values, but reduced EC, DEH and ALP values compared to corresponding lone compost amendment. Additionally, Act12 solubilized PTMs (Cd and Zn) in the soil, and accordingly enhanced the PTMs uptake in the plant. The phytoextraction indices viz. biological concentration factor (BCF), translocation factor (TF) and metal extraction amount (MEA) indicated that compost and Act12 had a synergistic role in enhancing the phytoremediation efficiency, among which MEA values of Cd and Zn maximally increased by 9.64 and 11.4 folds, respectively, compared to control. Redundancy analysis (RDA) indicated that phytoextraction indices correlated well with soil parameters. Our results suggested that manure compost associated with Act12 is a potential strengthening strategy in phytoremediation of PTMs contaminated soil.

Succession and the Relationship between Vegetation and Soil in the Marl Quarries of the Yucatan Peninsula, Mexico

Open-pit mining is a common activity in the Yucatan Peninsula for the extraction of limestone. These areas are characterized by the total removal of the natural vegetation cover and soil in order to access calcareous material. The present study shows the composition and structure of the vegetation in five quarries after approximately ten years of abandonment, and the target vegetation near to the quarries in southeastern Mexico. A linear mixed model showed that P availability is one of the limiting factors for species establishment in the quarries. Using a canonical correspondence analysis (CCA), the distribution of the species was determined in relation to the edaphic variables: soil depth, the percentage of organic matter (OM), cationic exchange capacity (CEC), pH and texture. Twenty-six families, 46 genera and 50 species were recorded in the quarries, and 25 families, 45 genera and 47 species were recorded in the conserved areas. The dominant species in the quarries belong to the families Poaceae, Fabaceae, Rubiaceae and Anacardiaceae. The quarries with higher values of OM (2%), CEC (24 Cmol/kg), depth (11 cm) and sand percentage (31%) include the following species Lysiloma latisiliquum (L.) Benth., Metopium brownei (Jacq.) Urb. and Bursera simaruba (L.) Sarg., which are common in secondary forests. Quarries with lower values of OM (0.4%), CEC (17 Cmol/kg) and depth (5.02), and with a higher percentage of silt (42%) were dominated by herbs belonging to Poaceae and by Borreria verticillate (L.) G. Mey., which are typical in disturbed areas of southeastern Mexico. In all cases, the pH was slightly alkaline due to the content of calcium carbonate (CaCO3), characteristic of the soils of the region.

Organic matter in rock–water systems of petroliferous basins: interrelationships (a case study: South Caspian Basin)

Generalizations and analyses are given of the data accumulated to date on the content of Organic Matter (OM) in formation waters of various stratigraphic complexes, as well as of mud volcanoes, and the correlation with OM in South Caspian Basin (SCB) sedimentary rocks. Results are based on about 300 analyses of formation waters and waters of mud volcanoes, as well as on more than 400 analyses of the content of OM in rocks (outcrops and wells from both onshore and offshore petroleum fields of the SCB). The stratigraphic interval covers the period from the Lower Pliocene to the Jurassic, and the depth interval from 73 m to 6043 m. In these intervals, the values of Dissolved Organic Matter (DOM) in reservoir waters vary from 4.1 mg/L to 271.2 mg/L, averaging (219 analyses) 48.9 mg/L. A good correlation has been established between the values of DOM and OM in rocks. Paleogene and Jurassic rocks have the highest correlations. DOM varies with depth with an increase in value from a depth of about 3.3 km, likely due to catagenetic transformation of OM into hydrocarbons in the rock–water system. The highest values of DOM are for waters with mineralization less than 50 g/L. Mud volcano waters are characterized by low levels of DOM and low mineralization, likely due to the condensate nature. The results of the studies show that underground water, as one of the components of a single rock–water system of the Earth’s sedimentary cover, together with the rocks, participates in the processes of hydrocarbon generation and migration.

Effects of Soil Properties on Cadmium Toxicity to Folsomia candida (Collembola).

The study was endeavored to investigate the effects of soil properties on the acute and chronic cadmium (Cd) toxicities to Folsomia candida (Collembola F. candida). Results of the present study indicated that 10% lethal concentrations (LC10) in a period of 7days were ranged from 68.6 to > 1000mg/kg Cd. Soil Cd concentrations that halve F. candida reproductions (EC50, 28days) were ranged from 41.4 to 146.8mg/kg. Stepwise regression analysis between the thresholds of Cd toxicity and soil properties revealed that the pH and organic matter (OM) were two fundamental factors for the assessment of biological threats posed by Cd. The exchangeable Cd was mainly affected by soil pH. The reproduction inhibition and adult mortality ratios of F. candida were positively correlated with soil exchangeable Cd. The development of a comprehensive pedotransfer function based on pH and OM values would be suitable for accurately assessing the biological risks arising from Cd contamination.