The effects of organic matter concentration on sediment reworking of Perinereis aibuhitensis : a mesocosm study

2020 ◽  
Author(s):  
Jaehwan Seo ◽  
Bon Joo Koo
Keyword(s):  
Organic Matter ◽  
Feeding Activity ◽  
Transport Rate ◽  
Benthic Organism ◽  
Mean Values ◽  
Sediment Reworking ◽  
Pellet Production ◽  
Organic Matter Concentration ◽  
Perinereis Aibuhitensis ◽  
The Mean

<p>The organic matter (OM) concentration is one of the most important factors influencing benthic organism sediment reworking during bioturbation. This study was designed to evaluate differences in sediment reworking rate of Perinereis aibuhitensis based on quantification of its pellet production (PP) and OM transport rate from ambient sediment to the surface due to its feeding. The mesocosm experiment was conducted in acrylic container (15×1×20 cm) with two treatments (high OM treatment and low OM treatment) and each treatment had ten replicates. The pellets in each container were removed 2h before the beginning of the pellet collection, and then newly produced pellets were collected every 2 h during 24 h at each treatment. The mean grain size of pellets (5.1 ∅) was smaller than that of ambient sediment particles (5.9 ∅), and the mean OM concentration was much higher in pellet (0.69% for C and 0.06% for N) than in ambient sediment (0.46% for C and 0.05% for N). Since an organism cannot produce more organic matter than it ingests, production of organically enriched pellets by this species indicates selective ingestion. The overall OM transport rate was 0.7 g C m<sup>-2</sup> day<sup>-1</sup> in carbon and 0.06 g N m<sup>-2</sup> day<sup>-1 </sup>in nitrogen, respectively. The daily PP was much higher in high OM treatment than that of low OM treatment with mean values of 0.007 and 0.002 g ind.<sup>-1</sup> h<sup>-1</sup>, respectively. It is expected that Perinereis feeding activity strongly depended on OM concentrations. The overall sediment reworking rate based on the pellet production was much higher in high OM concentration (0.005 mm day<sup>-1</sup>) than in low OM (0.001 mm day<sup>-1</sup>) concentration.</p>

scholarly journals Properties of Humic Acids in Meadow Soils Irrigated with the Slope-and-Flooding System

Agronomy ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2553
Author(s):  
Magdalena Banach-Szott ◽  
Andrzej Dziamski ◽  
Maciej Markiewicz
Keyword(s):  
Organic Matter ◽  
Carbon Sequestration ◽  
Soil Organic Matter ◽  
Organic Carbon ◽  
Humic Acids ◽  
Infrared Spectra ◽  
Soil Protection ◽  
Mean Values ◽  
Irrigation Ditch ◽  
The Mean

The still-advancing soil degradation and the related losses of soil organic carbon stocks due to the limited inflow of organic residues in agro-ecosystems encourage more and more soil protection. Establishing meadow ecosystems is one of the key methods of agricultural land use preventing losses of organic carbon in soils. Based on the research on the properties of humic acids, it is possible to determine the advancement of the processes of transformation and decomposition of soil organic matter. The obtained results may allow for the development of a soil protection strategy and more effective sequestration of organic carbon. Therefore, the aim of the research was to determine the properties of humic acids defining the quality of organic matter of meadow soils irrigated for 150 years with the slope-and-flooding system. The research was performed based on the soils (Albic Brunic Arenosol) sampled from Europe’s unique complex of permanent irrigated grasslands (the same irrigation management for 150 years), applying the slope-and-flooding system: the Czerskie Meadows. The soil samples were assayed for the content of total organic carbon (TOC) and the particle size distribution. HAs were extracted with the Schnitzer method and analysed for the elemental composition, spectrometric parameters in the UV-VIS (ultraviolet-visible) range, hydrophilic and hydrophobic properties and the infrared spectra. The research results showed that the HAs properties depend on the depth and the distance from the irrigation ditch. The HAs of soils sampled from the depth of 0–10 cm were identified with a lower “degree of maturity” as compared with the HAs of soils sampled from the depth of 20–30 cm, reflected by the values of atomic ratios (H/C, O/C, O/H), absorbance coefficients, and the FT-IR (Fourier transform infrared) spectra. The mean values of the H/C ratio in the HAs molecules of soils sampled from the depth of 20–30 cm were lower by 8.2% than those from the depth of 0–10 cm. The mean values of the absorbance coefficient A4/6 in the HAs molecules of soils sampled from the depth of 20–30 cm were lower by 9.6% than in the HAs molecules of soils sampled from the depth of 0–10 cm. The HAs molecules of the soils sampled 25 m from the irrigation ditch were identified with a higher degree of humification, as compared with the HAs of the soils sampled 5 m from the irrigation ditch. The results identified that humic acids produced in the many-year irrigated sandy soils were identified with a high degree of humification, which proves the relative stability of the soil’s organic matter. It confirms the importance of meadow soils for the carbon sequestration process. It should also be emphasized that the research area is interesting, although hardly described in terms of organic matter properties. Further and more detailed applicable research is planned, e.g., monitoring of total organic carbon content and comparing the properties of irrigated and non-irrigated meadow soils. Continuity of research is necessary to assess the direction of the soil organic matter transformation in such a unique ecosystem. The obtained results may allow for the development of, inter alia, models of agricultural practices that increase carbon sequestration in soils. In the long term, this will allow for greater environmental benefits and, thus, also increased financial benefits.

The use of internal markers to estimate herbage digestibility and intake: 1. Potentially indigestible cellulose and acid insoluble ash

1983 ◽  
Vol 100 (1) ◽  
pp. 127-131 ◽  
Author(s):  
P. D. Penning ◽  
R. H. Johnson
Keyword(s):  
Organic Matter ◽  
Close Agreement ◽  
Live Weight ◽  
Mean Values ◽  
Large Numbers ◽  
The Mean ◽  
Mean Differences ◽  
Internal Markers

SUMMARYConcentrations of potentially indigestible cellulose (PIC) and acid insoluble ash (AIA) were determined in samples of feed and faeces in a study to determine their value as internal markers. PIC and AIA were then used to predict the organic-matter digestibilities (OMD) of samples of perennial ryegrass (Lolium perenne) and lucerne (Medicago sativa)of known OMD which had been determined using wether sheep. The mean values for OMD (%) measured in vivo were 67·2 and 62·8 for ryegrass and 58·0 and 55·8 for lucerne at intakes of 15 and 25 g D.M./kg live weight, respectively.The in vitro digestibility technique, using rumen liquor, gave OMD values of 69·5 and 57·4 for ryegrass and lucerne which are in close agreement with the in vivo values at the lower level of intake.The mean differences between OMD measured in vivo and that estimated using PIC were: -1·1 (± 0·65) and -1·6 (± 0·46) percentage units for ryegrass and lucerne respectively, and using AIA were: -1·4 (± 0·57) and -3·5 (± 1·61).For the two feeds tested, OMD was predicted more precisely by PIC than by AIA or the in vitro digestibility technique. However, the PIC technique required the use of rumen-fistulated animals and 10 days to digest samples of faeces; this may make the technique impractical if large numbers of determinations of PIC are required.

scholarly journals Case study of geochemical clustering as a tool for tracing sources of clays for archaeological and modern bricks

Baltica ◽  
2019 ◽  
Vol 32 (2) ◽  
pp. 139-155
Author(s):  
Ričardas Taraškevičius ◽  
Vaidotas Kazakauskas ◽  
Saulius Sarcevičius ◽  
Rimantė Zinkutė ◽  
Sergej Suzdalev
Keyword(s):  
Organic Matter ◽  
Hierarchical Clustering ◽  
Clay Material ◽  
Clustering Methods ◽  
Geochemical Composition ◽  
Complete Linkage ◽  
Mean Values ◽  
Pair Group ◽  
The Mean

The study was conducted using 14 hierarchical clustering ways and combining them with 4 inter-related sets of elements, i.e. the contents of Al, Ba, Ca, Fe, Ga, K, Mg, Mn, Na, Nb, P, Rb, Si, Sr, Th and Ti determined by EDXRF in 44 splits of 10 archaeological and 4 modern bricks, as well as in 38 clay samples from two quarries. Empirical scoring of tree dendrograms of archaeological samples helped to identify Complete Linkage, Weighted Pair Group Average and Ward’s methods as the most suitable for sourcing. Successful identification of geochemical clustering methods for fingerprinting sources of bricks is determined by the intrinsic features of the geochemical composition of stonework or quarries: their similarity, determined by the geochemical peculiarities of clay indicators, such as Al, Rb, Ga, K, Th, Fe, Ti and Nb, and differences, expressed by the elements that are more abundant in sands and silts (Si, Na), carbonates (Ca, Sr, Mg), organic matter (P) and other lithological-mineralogical tracers. It has been found that the mean values of the geochemical composition of the allied objects have much more useful fingerprinting properties. It is strongly recommended for source fingerprinting to select not only typical lithological-mineralogical samples, but also homogeneous sampling sets excluding possible outliers. It has been shown that each raw clay material has its own specific geochemical features. This is an essential useful feature for source fingerprinting using clustering of the objects of interest.

scholarly journals Herzfrequenz, Aktivitäts- und Ruhezeiten sowie Wachstumsleistung von in Gruppen mit Tränkeautomatenfütterung gehaltenen Milchrindkälbern während der Aufzucht im Winter und Frühjahr

2002 ◽  
Vol 45 (4) ◽  
pp. 359-373
Author(s):  
M. Steinhardt ◽  
H.-H. Thielscher
Keyword(s):  
Heart Rate ◽  
Circadian Rhythm ◽  
Feeding Activity ◽  
Growth Period ◽  
Total Activity ◽  
Dairy Calves ◽  
Interindividual Variation ◽  
Mean Values ◽  
Physiological Variables ◽  
The Mean

Abstract. Title of the paper: Heart rate, activity and resting times and growth in group reared feeder-fed dairy calves reared at transition from winter to spring To characterize the food entrainable oscillator and/or light entrainable oscillator determined rhythmicity of physiological variables of feeder-fed dairy calves reared at transition from winter to spring (35 German Holstein Friesian, 2 German Red Pied, 17 male and 20 female) long term heart rate recordings were taken at 5 , 15, 40 and 60 days of age using Polar Sport Tester, from which the number and duration of activity (ZDA) and rest periods (ZDR) and the total activity (GZA) and rest times (GZR) could be established. For these periods characteristic heart rate values were calculated (HFA and HFR) and they were analysed for daytime periods of three hours duration at different life ages. HF of feeder-fed dairy calves showed substantial interindividual variation and a high individual specificity. Mean HFA and HFR were significantly smaller at 15 and 40 days then at 5 and 60 days of age. HFA and HFR showed a high correlation and the mean values of HFA and HFR were allways significantly different. More profound increases of HF (HFA-HFR) could be observed at feeding and service times. Individual level of HFA and HFR changed regularly with daytime, but mean values were significantly different between daytime periods only at some age points. Deviation of HFA and HFR from the mean of the individual daytime heart rate recording followed a circadian rhythm that became more obvious with advanced development and adaptation of the animals in case of HFA and HFR. For the means of the deviations of HFA and HFR significant differences between the daytime periods could be found. The mean ZDA and the quotient GZA/GZR were greater at 40 and 60 days of age then at 5 and 15 days of age. ZDA and ZDR showed great variation and presented rhythmic changes during the course of the day. The means of ZDA and ZDR were significantly different between the daytime periods of three hours duration at the age points excluding that of ZDA for 15 days of age. Results show the establishment and the prevalence of a circadian rhythm of heart rate at the early growth period in feeder-fed dairy calves reared at transition from winter to spring and how this was superimposed by feeding activity around the programmed daytimes of feed access at the start of rearing.

The contribution of clay and organic matter to the cation exchange capacity of the soil

1958 ◽  
Vol 51 (1) ◽  
pp. 1-3 ◽  
Author(s):  
E. G. Hallsworth ◽  
G. K. Wilkinson
Keyword(s):  
Organic Matter ◽  
Cation Exchange ◽  
Mineralogical Composition ◽  
Exchange Capacity ◽  
Regression Analyses ◽  
Partial Regression ◽  
Mean Values ◽  
Agricultural Chemistry ◽  
The Mean ◽  
The University

Partial regression analyses have been used to calculate mean values for the cation exchange capacities of the clay and organic matter from five groups of soils.It has been found that figures obtained for exchange capacities of the clays were in accord with what was known of their mineralogical composition. The corresponding figures for humus differed widely, the differences approaching significance, and were related to the mean pH of the soil group concerned.The data on which this paper is based were obtained when the authors were at the Agricultural Chemistry laboratories of the University of Sydney, to the Research Grants Committee of which they are greatly indebted for generous financial assistance. They are particularly indebted to Dr G. Wilkinson, C.S.I.R.O., Division of Statistics, Adelaide, for helpful discussions, to Miss H. V. Rayner and Miss J. Walker for certain of the analyses.

scholarly journals Mineral, protein and nitrate contents in leaves of Pereskia aculeata subjected to nitrogen fertilization

2016 ◽  
Vol 46 (1) ◽  
pp. 43-50 ◽  
Author(s):  
Maria Regina de Miranda Souza ◽  
Paulo Roberto Gomes Pereira ◽  
Ivan de Paiva Barbosa Magalhães ◽  
Maria Aparecida Nogueira Sediyama ◽  
Sanzio Mollica Vidigal ◽  
...  
Keyword(s):  
Organic Matter ◽  
Protein Content ◽  
Nitrogen Fertilization ◽  
Organic Matter Content ◽  
Matter Content ◽  
Fresh Mass ◽  
Mass Yield ◽  
Mineral Contents ◽  
Mean Values ◽  
The Mean

ABSTRACT Considering that nitrogen is directly related to leaf protein content, the nitrogen fertilization in Pereskia aculeata plants may affect the protein content and increase its nutritional potential. This study aimed at assessing the effect of nitrogen fertilization on mineral, protein and nitrate contents, as well as the yield of P. aculeata leaves. A randomized blocks design was used, with three replications and five treatments, consisting of increasing topdressing nitrogen doses (0-400 kg ha-1), in soil with organic matter content of 4.0 dag kg-1. Three harvests were performed for leaf analysis. No significant effect was observed for mineral and protein content or leaf fresh mass yield. The mean values for mineral composition were: 3.52 dag kg-1 of N, 0.47 dag kg-1 of P, 4.65 dag kg-1 of Ca, 0.71 dag kg-1 of Mg, 0.25 dag kg-1 of S, 36.64 mg kg-1 of Zn and 174.13 mg kg-1 of Fe. The mean content for protein was 21.86 % and the leaf fresh mass yield was 0.971 kg plant-1. K levels decreased from 50 kg ha-1 of N. Nitrate increased linearly with the nitrogen fertilization, reaching a maximum value of 78.2 mg kg-1 of fresh mass, well below the health risk threshold. It was concluded that a soil with high organic matter content does not require nitrogen fertilization. However, doses up to 400 kg ha-1 of nitrogen ensure adequate leaf yield and protein and mineral contents within the desired range for the species, being a food rich in proteins, iron and calcium.

scholarly journals Assessing Soil and Crop Characteristics at Sub-Field Level Using Unmanned Aerial System and Geospatial Analysis

2021 ◽  
Vol 13 (5) ◽  
pp. 2855
Author(s):  
Antonis V. Papadopoulos ◽  
Dionissios P. Kalivas
Keyword(s):  
Organic Matter ◽  
Soil Properties ◽  
Total Nitrogen ◽  
Circular Economy ◽  
Crop Production ◽  
Clay Content ◽  
Unmanned Aerial System ◽  
Mean Values ◽  
The Mean ◽  
Reflectance Data

Practicing agriculture is a multiparametric and for this reason demanding task. It involves the management of many factors and thorough strategic planning in a highly variable and uncertain environment. Crop production is a function of agricultural practices as applied in natural resources, such as soil and plants. When referring to conventional agriculture, variability in these resources is neglected, as any field is treated homogenously. On the other hand, site-specific crop management, which was promoted through the advance of technologies, regarding collecting and analyzing data and applying agricultural decisions at a sub-field level, considers field spatial and temporal variations. Localizing inputs in a field rationalizes agricultural waste management and offers promising perspectives towards a circular economy. In this context, two cotton fields in central Greece were selected for this study. During the growing period, reflectance data were acquired, before planting at the end of April, and 100 days after planting at the end of July, with a commercial unmanned aerial system (UAS). The fields were grid sampled for soil (clay content, pH, calcium carbonate percentage, organic matter, total nitrogen, and electrical conductivity) and plant properties (total nitrogen, potassium, iron, copper, and zinc) determination. All data were manipulated through geographical information systems (GIS) and further participated in principal component analysis (PCA) application. PCA revealed important relations and groupings between soil reflectance and organic matter, carbonates, and clay content in both fields (72 to 87% of the total variance in the initial parameters was explained by the extracted components). However, in plant data, the resulting components accounted for less variability in initial data (62 to 72%). PCA resulting scores were introduced in the Fuzzy c-means clustering algorithm, which categorized sub-areas of the fields into two discrete zones per field. Zoning, in the case of soil properties, was accompanied with the statistically important (p < 0.01) discrimination of the mean values (except for total nitrogen and pH), implicating a promising zonal management scheme. The zone delineation process regarding plant properties yielded areas that did not share statistically significant variations, except for the mean values of iron concentration (p < 0.01). According to the results, spatial variations were revealed across the fields, mostly in soil properties, which can be directly monitored through aerial reflectance data. The applied methodology can be used in extension services or by agronomists for producing fertilizer application maps. Further, when integrated with a broader spatial decision support system, it can be used by policy makers for adapting circular economy strategies in crop production.

Articulatory Behavior Pre and Post Full-Mouth Tooth Extraction and Alveoloplasty

1980 ◽  
Vol 23 (3) ◽  
pp. 630-645 ◽  
Author(s):  
Gerald Zimmermann ◽  
J.A. Scott Kelso ◽  
Larry Lander
Keyword(s):  
Control Subject ◽  
High Speed ◽  
Tooth Extraction ◽  
Kinematic Parameters ◽  
Experimental Conditions ◽  
Mean Values ◽  
Articulatory Movements ◽  
The Mean ◽  
Experimental Subjects ◽  
Normal Speech

High speed cinefluorography was used to track articulatory movements preceding and following full-mouth tooth extraction and alveoloplasty in two subjects. Films also were made of a control subject on two separate days. The purpose of the study was to determine the effects of dramatically altering the structural dimensions of the oral cavity on the kinematic parameters of speech. The results showed that the experimental subjects performed differently pre and postoperatively though the changes were in different directions for the two subjects. Differences in both means and variabilities of kinematic parameters were larger between days for the experimental (operated) subjects than for the control subject. The results for the Control subject also showed significant differences in the mean values of kinematic variables between days though these day-to-day differences could not account for the effects found pre- and postoperatively. The results of the kinematic analysis, particularly the finding that transition time was most stable over the experimental conditions for the operated subjects, are used to speculate about the coordination of normal speech.

Comparative Study of Intranasal, Subcutaneous and Intravenous Administration of Desamino-D-Arginine Vasopressin (DDAVP)

1986 ◽  
Vol 55 (01) ◽  
pp. 108-111 ◽  
Author(s):  
M Köhler ◽  
P Hellstern ◽  
C Miyashita ◽  
G von Blohn ◽  
E Wenzel
Keyword(s):  
Factor Viii ◽  
Von Willebrand Factor ◽  
Factor Xii ◽  
Additional Advantage ◽  
Mean Values ◽  
Routes Of Administration ◽  
The Mean ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Factor Antigen

SummaryThis study was performed to evaluate the influence of different routes of administration on the efficacy of DDAVP treatment. Ten healthy volunteers received DDAVP intranasally (i.n.), subcutaneously (s.c.) and intravenously (i.v.) in a randomized cross-over trial. Factor XII and high molecular weight (HMW)-kininogen levels increased only slightly after DDAVP administration. The mean increase of factor VIII: C was 3.1 (i. v.), 2.3 (s. c.), and 1.3 (i.n.) - fold over baseline. Ristocetin cofactor (von Willebrand factor antigen) increased 3.1 (2.5), 2.0 (2.3) and 1.2 (1.2) - fold over baseline mean values after i.v., s.c. and i.n. DDAVP, respectively. The half-disappearance time of factor VIII and von Willebrand factor (vWF) after DDAVP ranged from five (factor VIII: C) to eight hours (vWF). The mean increase of fibrinolytic activity was more pronounced after i.v. DDAVP. The antidiuretic effect was moderate with no apparent differences between the routes of application. This study provides further evidence that both i.v. and s.c. DDAVP administration result in an appropriate and reliable stimulation of haemostasis. An additional advantage of s. c. administration is its suitability for home treatment.

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