scholarly journals Pedogenic Processes in a Posidonia oceanica Mat

Soil Systems ◽  
2020 ◽  
Vol 4 (2) ◽  
pp. 18 ◽  
Author(s):  
Nerea Piñeiro-Juncal ◽  
Carmen Leiva-Dueñas ◽  
Oscar Serrano ◽  
Miguel Ángel Mateo ◽  
Antonio Martínez-Cortízas
Keyword(s):  
Organic Matter ◽  
Organic Matter Content ◽  
Principal Component ◽  
Posidonia Oceanica ◽  
Matter Content ◽  
Carbonate Content ◽  
Geochemical Processes ◽  
Seagrass Meadows ◽  
Physico Chemical ◽  
Pedogenic Processes

Scientists studying seagrasses typically refer to their substratum as sediment, but recently researchers have begun to refer to it as a soil. However, the logistics of sampling underwater substrata and the fragility of these ecosystems challenge their study using pedological methods. Previous studies have reported geochemical processes within the rhizosphere that are compatible with pedogenesis. Seagrass substratum accumulated over the Recent Holocene and can reach several meters in thickness, but studies about deeper layers are scarce. This study is a first attempt to find sound evidence of vertical structuring in Posidonia oceanica deposits to serve as a basis for more detailed pedological studies. A principal component analysis on X-Ray Fluorescence-elemental composition, carbonate content and organic matter content data along a 475 cm core was able to identify four main physico-chemical signals: humification, accumulation of carbonates, texture and organic matter depletion. The results revealed a highly structured deposit undergoing pedogenetical processes characteristic of soils rather than a mere accumulation of sediments. Further research is required to properly describe the substratum underneath seagrass meadows, decide between the sediment or soil nature for seagrass substrata, and for the eventual inclusion of seagrass substrata in soil classifications and the mapping of seagrass soil resources.

scholarly journals Parameter Selection for the Evaluation of Compost Quality

Agronomy ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1567
Author(s):  
Haydee Peña ◽  
Heysa Mendoza ◽  
Fernando Diánez ◽  
Mila Santos
Keyword(s):  
Electrical Conductivity ◽  
Organic Matter ◽  
Pore Space ◽  
Linear Regression Analysis ◽  
Organic Matter Content ◽  
Principal Component ◽  
Primary Component ◽  
Matter Content ◽  
Germination Index ◽  
Soil Restoration

This work studies variables measured from the first phase of composting through the acquisition of the final product, with the goal of identifying those that are more strongly related to quality and are most useful for developing an index. The necessity to establish quality control procedures thus exists for the classification of raw materials in the same way as for the finished products. To accomplish this, three mixtures were prepared, with the goal of achieving a C/N ratio of 30 and a moisture content of 60%. The primary component of each mixture was: fruit processing waste (C1), sewage sludge from the food industry (C2), and the manufacturing waste of fried foods (C3). Temperatures were measured over 107 days, with the corresponding data fit to a logistical model where T °C ~ α / ((1 + exp (− (Time − β) / − γ))) + δ, with interaction compost * time being statistically significant (p < 0.001). This allowed for the temperatures, in keeping with health concerns, to be confirmed. Likewise, a linear regression analysis demonstrated the decomposition of organic matter at 0.82%/week. Statistically, the parameters, measured during the process, with the least variability were selected, which differed in the average contrasts: germination index (cucumber), electrical conductivity, and average moisture. A principal component analysis (PCA) and Spearman’s correlation analysis revealed the best Germination Index (GI) values for C1, due to lower electrical conductivity (EC) and bulk density (Bd) along with higher organic matter content (TOM). For its part, C2 induced a higher Relative emergence (RE) of the cucumber thanks to its higher content of total nitrogen (TN) and lower contribution of Cu, Zn and K. C3 showed a higher presence of salts, less favorable physical characteristics (>Bd and <TPS, total pore space) and higher content of Zn and Cu. Composting carried out with appropriate mixtures can offer high-quality products for use as fertiliser, in soil restoration, and as an alternative substrate to peat and virgin mountain soil.

scholarly journals Variability of macrofauna distribution along a dissipative log-spiral sandy beach in Rio de Janeiro, Southeastern Brazil

2017 ◽  
Vol 81 (1) ◽  
pp. 111 ◽  
Author(s):  
Carlos A.M. Barboza ◽  
Tatiana Cabrini ◽  
Gustavo Mattos ◽  
Viviane Skinner ◽  
Ricardo Cardoso
Keyword(s):  
Grain Size ◽  
Organic Matter ◽  
Community Structure ◽  
Organic Matter Content ◽  
Principal Component ◽  
Matter Content ◽  
Southeastern Brazil ◽  
Individual Species ◽  
Beach Slope ◽  
Sediment Sorting

Log-spiral beaches display defined physical gradients alongshore. However, the majority of studies focus on the variability of a single population of macrofauna species. We aimed to investigate the variation in species distribution and in community structure along ten transects on a log-spiral beach. Principal component analysis indicated a clear physical gradient alongshore. Redundancy analysis showed that the sheltered end was related to smaller particle sizes, higher organic matter content and high densities of polychaetes. The exposed end was characterized by coarser sand, lower organic matter content and a high presence of crustaceans. Model selection indicated that the “best fit” to explain the variability in the number of individuals included grain size and beach slope. Variability of the polychaete Scolelepis squamata was best explained by grain size, slope and sediment sorting. The best model for the cirolanid Excirolana armata only included sediment sorting. The physical gradient in sediment texture and the beach slope explained more than one-third of the variability in community structure. The physical variables were also correlated with the distribution of the individual species. We showed that the physical gradient on log-spiral coasts may be an important driver of macrofauna variability, even at mesoscales and in dissipative conditions.

scholarly journals Physico-chemical characteristics of the seasonally flooded soils of Bangladesh and their management implications

1970 ◽  
Vol 20 (2) ◽  
pp. 173-182
Author(s):  
KF Akhter ◽  
ZH Khan ◽  
MS Hussain ◽  
AR Mazumder
Keyword(s):  
Organic Matter ◽  
Organic Matter Content ◽  
Chemical Properties ◽  
Exchange Capacity ◽  
Matter Content ◽  
Flooded Soils ◽  
Management Implications ◽  
Available N ◽  
Physico Chemical ◽  
Seasonally Flooded

The seasonally flooded soils of Bangladesh are unique in respect of several specific characteristics and contribute toward producing bulk of its staple food - mainly rice. Having fine texture these soils are similar to the “paddy soils” of Southeast Asian floodplains and have high production potential under proper management. Six representative soil series, viz. Arial, Debidwar, Naraibag, Jalkundi, Siddirganj and Tippera from the central region of Bangladesh have been studied to evaluate some of their intrinsic physico-chemical properties and their sustainable management requirements. These soils are slightly acidic to neutral and are negatively charged with ΔpH values ranging between –0.2 and –1.2. The organic matter content in the surface soil is relatively low that decreases steadily with depth. The cation exchange capacity (CEC) of the soils varies on the basis of their clay and organic matter contents while base saturation per cent (BSP) is high. The contents of available N, P, K and S and DTPA-extractable Fe, Mn, Cu and Zn in soils are moderate and are commensurate with the contents of colloidal fractions. These soils receive several mineral nutrients annually with the sediments deposited during the monsoon floods. The characteristics like organic matter content, particle size distribution, CEC, pH and BSP that have important management implications have been discussed. Key words: Seasonally flooded soils; Physical and chemical attributes; Management implications DOI: http://dx.doi.org/10.3329/dujbs.v20i2.8978 DUJBS 2011; 20(2): 173-182

A source of error in the estimation of the organic matter content of samples containing calcium carbonate

1972 ◽  
Vol 79 (3) ◽  
pp. 541-542 ◽  
Author(s):  
F. D. DeB. Hovell ◽  
E. R. Ørskov
Keyword(s):  
Organic Matter ◽  
Calcium Carbonate ◽  
Volatile Fatty Acids ◽  
Organic Matter Content ◽  
Matter Content ◽  
Carbonate Content ◽  
Apparent Digestibility ◽  
High Calcium ◽  
The Difference

The conventional method for the determination of the organic matter content of diets and faeces is by ashing the sample at 550 °C (A.O.A.C, 1965)Organic matter (O.M.) = dry matter (D.M.)–ash.If the sample contains calcium carbonate, then some of this carbonate will be converted to oxide (Vogel, 1951) and the weight of carbon dioxide evolved will be calculated as organic matter. The amount of carbonate converted will be dependent upon the temperature at which the sample is ashed and the duration of the ashing process. We have found (Ørskov, Hovell & Allen, 1966; Hovell & Greenhalgh, 1972) that when calcium salts of volatile fatty acids are included in diets given to sheep, most of the calcium is excreted in the faeces as carbonate, and since apparent digestibility is the difference between the amounts of nutrient ingested and excreted, the estimation of the apparent digestibility of organic matter will be in error if no correction is made for the high calcium carbonate content of the faeces. For example, a diet which contained 9·2% of calcium acetate had a true organic matterapparent digestibility of 86·8%. Had no correction been made this would have been estimated as 84·9%.

scholarly journals Molecular Characterization of Diazotrophic and Denitrifying Bacteria Associated with Mangrove Roots

2007 ◽  
Vol 73 (22) ◽  
pp. 7308-7321 ◽  
Author(s):  
Ana L. Flores-Mireles ◽  
Stephen C. Winans ◽  
Gina Holguin
Keyword(s):  
Organic Matter ◽  
Oxygen Concentration ◽  
Pore Water ◽  
Phylogenetic Trees ◽  
Organic Matter Content ◽  
Principal Component ◽  
Matter Content ◽  
Water Oxygen ◽  
Mangrove Roots ◽  
Biogeochemical Parameters

ABSTRACT An analysis of the molecular diversity of N2 fixers and denitrifiers associated with mangrove roots was performed using terminal restriction length polymorphism (T-RFLP) of nifH (N2 fixation) and nirS and nirK (denitrification), and the compositions and structures of these communities among three sites were compared. The number of operational taxonomic units (OTU) for nifH was higher than that for nirK or nirS at all three sites. Site 3, which had the highest organic matter and sand content in the rhizosphere sediment, as well as the lowest pore water oxygen concentration, had the highest nifH diversity. Principal component analysis of biogeochemical parameters identified soil texture, organic matter content, pore water oxygen concentration, and salinity as the main variables that differentiated the sites. Nonmetric multidimensional scaling (MDS) analyses of the T-RFLP data using the Bray-Curtis coefficient, group analyses, and pairwise comparisons between the sites clearly separated the OTU of site 3 from those of sites 1 and 2. For nirS, there were statistically significant differences in the composition of OTU among the sites, but the variability was less than for nifH. OTU defined on the basis of nirK were highly similar, and the three sites were not clearly separated on the basis of these sequences. The phylogenetic trees of nifH, nirK, and nirS showed that most of the cloned sequences were more similar to sequences from the rhizosphere isolates than to those from known strains or from other environments.

scholarly journals Characterisation of the geochemical heterogeneity of the Rupel Clay Member in the Netherlands

2016 ◽  
Vol 95 (3) ◽  
pp. 269-281 ◽  
Author(s):  
M. Koenen ◽  
J. Griffioen
Keyword(s):  
Organic Matter ◽  
The Netherlands ◽  
Clay Mineral ◽  
Clay Fraction ◽  
Organic Matter Content ◽  
Matter Content ◽  
Coarse Grained ◽  
Carbonate Content ◽  
X Ray ◽  
Boom Clay

AbstractSamples from Rupel Clay across the Netherlands were analysed for the assessment of its heterogeneity in geochemistry and mineralogy. X-ray fluorescence (XRF) and bulk and clay fraction X-ray diffraction (XRD) analyses of 152 samples from 17 different cores are presented and statistically interpreted. The results show a wide variation in the quartz, feldspar, clay mineral and carbonate content between the different samples. Factor analysis showed that the main variance between the samples can be explained by the clay mineral and quartz concentration, the carbonate content and pyrite plus organic matter. In the south of the Netherlands, the Rupel Clay is more quartz-rich and coarse grained. In addition, the clay is heterogeneous, varying with location and depth, consistent with observations for Belgium Boom Clay. Towards the north, the Rupel Clay becomes more clay-rich, finer grained and more homogeneous, both laterally and with depth. In addition, the clay has a relatively high carbonate and organic matter content. The pyrite content does not show any trends with location and depth. The differences between north and south are explained by the variations in depositional setting within the southern North Sea Basin.

scholarly journals Sediments of watersheds from Frutal and Bebedouro Streams (Frutal, MG, Brazil) as an indicator of human activities

2017 ◽  
Vol 12 (1) ◽  
pp. 17 ◽  
Author(s):  
Sofia Luiza Brito ◽  
Thiago Torres Costa Pereira ◽  
Inez Cristina Martins
Keyword(s):  
Organic Matter ◽  
Human Activities ◽  
Riparian Vegetation ◽  
Organic Matter Content ◽  
Principal Component ◽  
Quality Parameters ◽  
Matter Content ◽  
Particle Size Measurement ◽  
Minas Gerais State

Soil degradation is a physical process intensified by political and socioeconomic factors, and by the population growth of the 20th century. In this study, we evaluated the sediments of the Frutal and Bebedouro Streams, located in Frutal municipality, Minas Gerais State, Brazil, and their relation to major human activities that are responsible soil erosion and silting. Samples were collected between 2012 and 2013 for the determination of granulometric composition, organic matter content, and minerals in sediments. The Wentworth scale was used for particle size measurement, and then the size classes regrouped to ABNT scale (NBR 6502/1995). The results found that agriculture and cattle ranching are the main activities that cause intense erosion and silting in both watersheds. Bebedouro Stream is better preserved, as it is completely located in rural area with larger riparian vegetation, unlike the mid-stretch of Frutal Stream, which is located in an urban area. Quartz is the predominant mineral in the sediments as the soils of the region are formed by sandstones; consequently, few nutritional elements were found in the studied samples. Principal component analysis showed that water quality parameters are correlated to silt/clays and organic matter content in most of the collected stations.

scholarly journals Determination of the Atterberg Limits of Eemian Gyttja on Samples with Different Composition

2020 ◽  
Vol 42 (2) ◽  
pp. 168-178 ◽  
Author(s):  
Katarzyna Goławska ◽  
Zbigniew Lechowicz ◽  
Władysław Matusiewicz ◽  
Maria Jolanta Sulewska
Keyword(s):  
Organic Matter ◽  
Calcium Carbonate ◽  
Organic Matter Content ◽  
Liquid Limit ◽  
Matter Content ◽  
Carbonate Content ◽  
Test Results ◽  
Plastic Limit ◽  
Calcium Carbonate Content

AbstractThe paper presents the results of laboratory tests of plastic limit wP and liquid limit wL of Eemian gyttja characterized by different organic matter content Iom and calcium carbonate content CaCO3. Comparison of the liquid limit wL determined with the use of the Casagrande apparatus wLC and a cone penetrometer with cones having apex angles of 60° wL60 and 30° wL30 is shown. Based on statistical analysis of the test results, single- and two-factor empirical relationships for evaluating the plastic limit wP and liquid limit wL of Eemian gyttja depending on the organic matter content Iom and/or calcium carbonate content CaCO3 are presented in this study.

scholarly journals Pedological characteristics of soils in the watersheds of Oueds Nekôr and Ghiss (Central Rif; Morocco)

2021 ◽  
Vol 298 ◽  
pp. 04002
Author(s):  
Soukaina Ed Dakiri ◽  
Hatim Faiz ◽  
Jaouad Ouldchaib ◽  
Said El Moussaoui ◽  
Hajar El Talibi ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Organic Matter ◽  
Organic Matter Content ◽  
Matter Content ◽  
Alkaline Soils ◽  
Sparse Vegetation ◽  
Physico Chemical ◽  
Poorly Differentiated ◽  
Well Differentiated ◽  
Steep Slopes

The objective of this work is the pedological characterization of soils in the watersheds of Oueds Nekôr and Ghiss. Several profiles were identified and sampled for Physico-chemical and sedimentological analyses (color index, magnetic susceptibility, pH, granulometry, water content, organic matter, and carbonates). The watersheds in question are roughly characterized by a soft and diversified lithology, a sparse vegetation cover, and a semi-arid Mediterranean climate. The soils in the Oued Nekôr watershed are of the silty type (> 50%), not very developed and relatively well-drained, and become well-drained stony in the steep and eroded areas. Soil pH varies between 7 and 8, reflecting low alkaline to alkaline soils. In the Oued Ghiss watershed, the sandstone-limestone or marl-schist soils are poorly differentiated in the steep slopes. The well-drained soils are gravelly, relatively alkaline, and show the beginning of rubefaction. Very locally on wooded flats, the soil profiles can become deep and well-differentiated due to colluvial accumulation. The dark brown eluvial A horizon is relatively rich in organic matter (3.6%). The well individualized illuvial B horizon has strongly rubbed concretions and is richer in organic matter (4.6%). The light beige C horizon corresponds to the strongly altered marl and limestone parent rock with low organic matter content (1.3%) and very low magnetic susceptibility values.

Sign in / Sign up

Export Citation Format

Share Document