Dissolved organic carbon and potential for disinfection byproducts in Kranji, Pandan and Tengah reservoirs in Singapore

2008 ◽  
Vol 8 (4) ◽  
pp. 413-419
Author(s):  
C. B. Chidambara Raj ◽  
Tan Ee Kwong ◽  
Sharon Shi ◽  
Puah Aik Num
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
Organic Carbon ◽  
Pilot Plant ◽  
Pilot Scale ◽  
Disinfection Byproducts ◽  
Raw Water ◽  
Land Use Pattern ◽  
Urban Catchment ◽  
On Line

Fresh water from three western reservoirs of Singapore was assessed for the formation of trihalomethanes and the removal of precursors in a pilot-scale study. Raw water was processed through flocculation-sedimentation modules in a pilot plant with a capacity of 45 m3/day. Alum was the primary coagulant. Normal coagulation removed 10–60% of THM precursors. Kranji Reservoir, which has a watershed with thick vegetation, had relatively higher levels of dissolved organic matter with correspondingly higher potential for the formation of THM than Pandan Reservoir; Pandan is largely an urban catchment. Land-use pattern and proximity to seashore seem to influence THM formation. UV254 and SUVA were found to be better surrogates than DOC for THM. A benchmark criterion (UV254<0.08 cm−1) for on-line monitoring of THM was deduced from SDS-THM data and this criterion would vary slightly among the water works.

Land use change in Amazonian Dark Earth and Acrisol: Responses of organic carbon, organic matter composition and microbial carbon utilisation

2020 ◽  
Author(s):  
Klaus Jarosch ◽  
Luis Carlos Colocho Hurtarte ◽  
Konstantin Gavazov ◽  
Aleksander Westphal Muniz ◽  
Christoph Müller ◽  
...  
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
Community Structure ◽  
Microbial Community ◽  
Organic Carbon ◽  
Land Use Change ◽  
Microbial Community Structure ◽  
Secondary Forest ◽  
Soil Types ◽  
Amazonian Dark Earth

<p>The conversion of tropical forest for cassava cultivation is widely known to decrease the soil organic matter (OM) and nutrient contents of highly weathered soils in the tropics. Amazonian Dark Earth (ADE) might be affected less due to their historical anthropogenic amelioration with e.g. charcoal, ceramics and bones, leading to higher soil OM and nutrient concentrations. In this study, we analysed the effect of land use change on the OM dynamics and its composition under tropical conditions, using ADE and an adjacent Acrisol (ACR) as model systems. Soil samples were obtained south of Manaus (Brazil), from a secondary forest and an adjacently located 40-year-old cassava plantation. The land use change induced a severe decrease of organic carbon (OC) concentrations in ADE (from 35 to 15 g OC kg<sup>‑1</sup>) while OC in the adjacent ACR was less affected (18 to 16 g OC kg<sup>‑1</sup>). Soils were analysed by <sup>13</sup>C NMR spectroscopy to obtain information on how the conversion of secondary forest to cassava affected the chemical composition of OM. Our results show that land use change induces differences in the OM composition: The OM in ADE changes to a more decomposed state (increase of alkyl:O/N-alkyl ratio) whereas the OM in ACR changes to a less decomposed state (decrease of alkyl:O/N-alkyl ratio). According to a molecular mixing model, land use change influenced mostly the proportion of lipids, which might be related with a change of the plant input. The incubation of the soils with <sup>13</sup>C glucose enabled resolving how soil microorganisms were affected by land use change. In both soil types ADE and ACR, land use change caused a reduction of the total <sup>13</sup>C glucose respiration by approximately one third in a 7-days incubation, implying lower microbial activity. Microorganisms in both soil types appear to be more readily active in soils under forest, since we observed a distinct lag time between <sup>13</sup>C glucose addition and respiration under cassava planation. This indicated differences in microbial community structure, which we will assess further by determining the <sup>13</sup>C label uptake by the microbial biomass and the microbial community structure using <sup>13</sup>C PLFA analysis. Preliminary results from synchrotron-based STXM demonstrate a distinct arrangement of OM at fine-sized charcoal-particle interfaces. Samples of soils receiving <sup>13</sup>C label will be further analysed by NanoSIMS with the hypothesis that charcoal interfaces foster nutrient dynamics at the microscale. Despite the high loss of OC in the ameliorated ADE through land use change, the remaining OM might improve the nutrient availability thanks to charcoal interactions compared to the ACR. Our results contribute to a better understanding of the sensitivity of OM upon land use change and how the microbial community is responding to land use change in highly weathered tropical soils.</p>

The chemical and physical stability soil organic carbon in the top 1 m of the soil profile under different land uses in the UK

2020 ◽  
Author(s):  
Dedy Antony ◽  
Jo Clark ◽  
Chris Collins ◽  
Tom Sizmur
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Profile ◽  
Soil Depth ◽  
Physical Stability ◽  
Silty Clay ◽  
Land Uses ◽  
Total N

<p>Soils are the largest terrestrial pool of organic carbon and it is now known that as much as 50% of soil organic carbon (SOC) can be stored below 30 cm. Therefore, knowledge of the mechanisms by which soil organic carbon is stabilised at depth and how land use affects this is important.</p><p>This study aimed to characterise topsoil and subsoil SOC and other soil properties under different land uses to determine the SOC stabilisation mechanisms and the degree to which SOC is vulnerable to decomposition. Samples were collected under three different land uses: arable, grassland and deciduous woodland on a silty-clay loam soil and analysed for TOC, pH, C/N ratio and texture down the first one metre of the soil profile. Soil organic matter (SOM) physical fractionation and the extent of fresh mineral surfaces were also analysed to elucidate SOM stabilisation processes.</p><p>Results showed that soil texture was similar among land uses and tended to become more fine down the soil profile, but pH did not significantly change with soil depth. Total C, total N and C/N ratio decreased down the soil profile and were affected by land use in the order woodland > grassland > arable. SOM fractionation revealed that the free particulate organic matter (fPOM) fraction was significantly greater in both the topsoil and subsoil under woodland than under grassland or arable. The mineral associated OC (MinOC) fraction was proportionally greater in the subsoil compared to topsoil under all land uses: arable > grassland > woodland. Clay, Fe and Mn availability play a significant role (R<sup>2</sup>=0.87) in organic carbon storage in the top 1 m of the soil profile.</p><p>It is evidently clear from the findings that land use change has a significant effect on the dynamics of the SOC pool at depth, related to litter inputs to the system.</p>

scholarly journals Age distribution, extractability, and stability of mineral-bound organic carbon in central European soils

2020 ◽  
Author(s):  
Marion Schrumpf ◽  
Klaus Kaiser ◽  
Allegra Mayer ◽  
Günter Hempel ◽  
Susan Trumbore
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
Organic Carbon ◽  
Soil Depth ◽  
Age Distribution ◽  
Chemical Oxidation ◽  
Future Research ◽  
Soil Profiles ◽  
H2o2 Resistance ◽  
Depth Gradients

Abstract. The largest share of total soil organic carbon (OC) is associated with minerals. The portions and turnover of stable and faster cycling mineral-associated carbon (MOC) as well as the determining factors across different soils and soil depths are still unknown. Bioavailability of MOC is supposedly regulated by desorption but instead, its stability was so far mostly tested by exposure to chemical oxidation. Therefore, we determined the extractability of MOC into a mixture of 0.1 M NaOH and 0.4 M NaF as a measure for maximal potential desorbability, and compared it with maximal potential oxidation in heated H2O2. We selected samples of three soil depth increments (0–5 cm, 10–20 cm, 30–40 cm) of five typical soils of the mid-latitudes, differing contents of clay and pedogenic oxides, and being under different land use. Extracts and residues were analyzed for OC and 14C contents, and further chemically characterized by CPMAS-13C-NMR. We hypothesized NaF-NaOH extraction to remove less and younger MOC than H2O2 oxidation, and extractable MOC to be less and relatively older in subsoils and soils with high contents of pedogenic oxides. A surprisingly constant portion of 58 ± 11 % (standard deviation) of MOC was extractable across soils, independent of depths, mineral assemblage, or land use. NMR spectra revealed strong similarities of the extracted organic matter, with more than 80 % of OC in the O/N alkyl and alkyl C region. Total MOC amounts were linked to the content of pedogenic oxides across sites, independent of variations in total clay. The uniform MOC desorption could therefore be the result of pedogenic oxides dominating the overall response of MOC to extraction. While bulk MO14C values suggested differences in OC turnover between sites, these were not linked to differences in MOC extractability. As expected, OC contents of residues had smaller 14C contents than extracts, suggesting that non-extractable OC is older. However, 14C contents of extracts and residues were strongly correlated and proportional to bulk MO14C, but not dependent on mineralogy. Also along soil profiles, where increasing MOC ages indicate slower turnover with depth, neither MOC extractability nor differences in 14C between extracts and residues changed. Increasing bonding strength with soil depths did therefore not cause the 14C depth gradients in the studied soils. Although H2O2 removed 90 ± 8 % of the MOC, the 14C content of the OC removed was similar to that of the NaF-NaOH-extracted OC, while oxidation residues were much more 14C-depleted. Different chemical treatments apparently remove OC of the same continuum, leaving increasingly older residues behind the more OC being removed. Different from the extractions, higher contents of pedogenic oxides seemingly slightly increased the oxidation-resistance of MOC, but this higher H2O2-resistance did not coincide with older MOC or oxidation residues. Our results indicate that total MOC was dominated by OC interactions with pedogenic oxides rather than clay minerals, so that no difference in MOC extraction in NaF/NaOH, and thus, bond type or strength between clay-rich and poor sites was detectable. This suggests that site-specific differences in MO14C and their depth declines are driven by the accumulation and exchange rates of OC at mineral surfaces. Accordingly, future research on M14OC should focus on soil and ecosystem properties driving dissolved organic matter formation, composition and transport along soil profiles.

scholarly journals Agricultural Land Use and Management Practice Influence on Efflux and Influx of Carbon between Soil and the Atmosphere: A Review

2020 ◽  
pp. 31-48
Author(s):  
M. B. Hossain
Keyword(s):  
Carbon Dioxide ◽  
Land Use ◽  
Organic Matter ◽  
Management Practices ◽  
Agricultural Land ◽  
Soil Depth ◽  
Management Practice ◽  
Wetland Soil ◽  
Land Use Pattern ◽  
Land Use And Management

The objective of this paper is to formulate suitable policies and management practices that can firmly reduce CO2–C (carbon dioxide –carbon) emissions and sequester it in a sustainable way. Land use and management practices can influence both efflux and influx of carbon between soil and the atmosphere. Organic matter dynamics and nutrient cycling in the soil are closely related to nutrient immobilization and mineralization. Unplanned conversion of lands to agricultural production causes a sharp decrease in carbon stored in soil. In the atmosphere, 4.0 Gt C yr-1 is enriched by different sources. Increasing soil organic carbon (SOC) improves soil health and mitigate climate change. Histosol, clayey and fine particle size have good capacity to sequestrate C in soil. Land use pattern controls organic matter status in soil. Crop/grass, forestry/agroforestry, reduced tillage, quality of organic matter, soil biotic - abiotic are the major factors to sequestrate significant C in soil. The application of fertilizers especially nitrogen usually results in an increase in crop growth as well as a corresponding increase in root development takes place for building up active organicmatter in soil. Biochar amendments can impact soil C storage and net CO2 removals from the atmosphere in three different ways such as longer residence time due to resistant to microbial decay, plant productivity and reduce N2O emission. Wetland soil, effective management practices and control deforestation sequestrate 0.2, 2.0 and 1.6 Gt C yr-1, respectively. Based on these information, it is possible to increase 4‰ carbon a year the quantity of carbon contained in soils at 0-40 cm soil depth to halt carbon dioxide enrichment (4.0 Gt C yr-1) in the atmosphere.

scholarly journals Oxidizable fraction of organic carbon in an Argisol under different land use systems

CERNE ◽  
2012 ◽  
Vol 18 (2) ◽  
pp. 215-222 ◽  
Author(s):  
Caio Batista Müller ◽  
Oscarlina Lúcia dos Santos Weber ◽  
José Fernando Scaramuzza
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Organic Carbon ◽  
The Other ◽  
Control Treatment ◽  
Native Vegetation ◽  
Labile Carbon ◽  
Land Use Systems ◽  
Oxidizable Fraction

The objective of this study was to evaluate carbon input in labile and stable fractions in an ARGISOL of northwestern Brazil under different land use systems. Use systems being evaluated include: forest - MA (reference), agrosilvopasture - TCP (teak, cocoa and pasture); agroforest - TC (teak and cocoa); teak forest at 8 and 5 years - T8 and T5, and pasture - PA. In each system three furrows were made at depths of 0-5 cm, 5-10 cm and 10-20 cm. An area consisting of native vegetation (forest) adjacent to the experiment was sampled and used as control treatment. The use systems MA, T8 and T5 had higher levels of total organic carbon (COT) and the MA system had higher levels of labile carbon (CL) than the other systems, with the exception of TC at a depth of 10-20 cm. In the MA system, COT levels were higher in comparison to use systems TCP, TC and PA while CL levels were higher than the levels observed in use systems TCP and TC. In most cases being analyzed, CL levels were lower than COT levels, therefore this trait can be used as an indicator to assess anthropogenic changes relating to the maintenance or condition of soil organic matter.

Biofiltration of Ozonated Humic Water in Expanded Clay Aggregate Filters

1999 ◽  
Vol 40 (9) ◽  
pp. 165-172 ◽  
Author(s):  
E. S. Melin ◽  
H. Ødegaard
Keyword(s):  
Organic Matter ◽  
Steady State ◽  
Loading Rate ◽  
Glyoxylic Acid ◽  
Treatment Plant ◽  
Good Alternative ◽  
Pilot Scale ◽  
Raw Water ◽  
Methyl Glyoxal ◽  
By Products

Treatment of humic water was studied in a pilot-scale ozonation/biofiltration treatment plant. The raw water had TOC and CODMn concentrations of 3.2-5.0 and 4.1-6.6 mgO 1−1, respectively, and colour (410 nm) of 30-50 mgPt 1−1. The effect of biofilter loading rate on removal of organic matter and ozonation by-products was investigated in two upflow biofilters containing expanded clay aggregate (Filtralite) media. The empty bed contact times ranged from 11 to 54 min. The TOC removals varied from 18 to 37% and the CODMn removals from 30 to 48% with ozone dosages from 1.0 to 1.7 mgO3 mgTOC−1. The ozone dosage seemed to have larger effect on removal efficiency than the loading rate. Concentrations of aldehydes (sum of formaldehyde, acetaldehyde, glyoxal and methyl glyoxal) were 41-47 μg 1−1 in ozonated water. Formaldehyde and glyoxal were the only aldehydes detected from the biofilter effluents at concentrations higher than 1 μg 1−1, but their mean concentrations were below 2.1 μg 1−1. The ketoacid concentrations (sum of glyoxylic, pyruvic and ketomalonic acids) ranged from 272 to 441 μg 1−1. Average biofilter effluent concentrations varied from 5.3 (glyoxylic acid) up to 67 μg 1−1 (ketomalonic acid) with steady-state reductions generally over 80%. The aldehydes and ketoacids accounted on average for 16% of the biodegraded TOC. The results show that expanded clay aggregate media is a good alternative as biofilter material.

scholarly journals ORGANIC CARBON AND TOTAL NITROGEN IN THE DENSIMETRIC FRACTIONS OF ORGANIC MATTER UNDER DIFFERENT SOIL MANAGEMENT

2016 ◽  
Vol 29 (2) ◽  
pp. 263-273 ◽  
Author(s):  
MARCELO RIBEIRO VILELA PRADO ◽  
FABRICIO TOMAZ RAMOS ◽  
OSCARLINA LÚCIA DOS SANTOS WEBER ◽  
CAIO BATISTA MÜLLER
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Organic Carbon ◽  
Total Nitrogen ◽  
Agroforestry System ◽  
Native Forest ◽  
Land Use Systems ◽  
System 2 ◽  
Heavy Fractions

ABSTRACT: The evaluation of land use and management by the measurement of soil organic matter and its fractions has gained attention since it helps in the understanding of the dynamics of their contribution to soil productivity, especially in tropical environments. This study was conducted in the municipality of Colorado do Oeste, state of Rondônia, Brazil and its aim was to determinethe quantity of organic carbon and total nitrogen in the light and heavy fractions of organic matter in the surface layers of a typic hapludalf under different land use systems: Native Forest: open evergreen forest, reference environment; Agroforestry System 1: teak (Tectona grandis LF) and kudzu (Pueraria montana); Agroforestry System 2: coffee (Coffea canephora), marandu palisade grass (Brachiaria brizantha cv. Marandu), "pinho cuiabano" (Parkia multijuga), teak and kudzu.; Agroforestry System 3: teak and cocoa (Theobroma cacao); Silvopasture System: teak, cocoa and marandu palisade grass; and Extensive Grazing System: marandu palisade grass. The experimental design was a randomized block in split-split plots (use systems versus soil layers of 0-0.05 and 0.05-0.10 m) with three replications. The results showed that relative to Native Forest, the Agroforestry System 2 had equal- and greater amounts of organic carbon and total nitrogen respectively (light and heavy fractions) in the soil organic matter, with the light fraction being responsible for storage of approximately 45% and 70% of the organic carbon and total nitrogen, respectively. Therefore, the light densimetric fraction proved to be useful in the early identification of the general decline of the soil organic matter in the land use systems evaluated.

Effects of mineral and organic fertilizers on soil organic carbon fractions in agricultural chestnut soil

2018 ◽  
Vol 22 (03) ◽  
pp. 103-108
Author(s):  
Enkhtuya D ◽  
Tuul D ◽  
Munkhtsetseg T
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Fertility ◽  
Active Form ◽  
Chestnut Soil ◽  
Organic Fertilizers ◽  
Stable Form ◽  
Organic C

Soil organic matter can be analyzed on the basis of the different fractions. Changes in the levels of organic matter, caused by land use, can be better understood by alterations in the different fractions. Therefore in order to discover tendency of soil fertility sustainability it is significant to research on stable and labile form fractions of soil organic carbon by advanced methodology and modern technique. Our research work aimedto evaluate the effect of mineral and organic fertilizers on the labile and stable organic carbon of the chestnut soil in Mongolia. The soils samples used in this study we collected from variants of mineral (N60P40K40), organic (biohumus 1t / hec.) Fertilizer and their combination of the Long-term fertilizers experiments of Plant and Agriculture Institute Changes in soil organic C by land use for agricultural purposes occurred mainly in the fraction of particulate organic matter (> 20 μm). The clay and silt fractions were quatified with a Mastersizer S after distruction organic substances and carbonates using H2O2 and HCI and the sand fraction was determined by wet sieving. According to our research, the stable form of organic carbon in chestnut soil is 39, 0-40,1% of the total fine particle size and 59, 9-61,0% of the active form fraction. On the other hand, variants with fertilizer tend to have increased stabile composition of soil organic carbon. It indicates that soil fertility protection and increased stability are possible in the country’s agricultural technology if use mineral and organic fertilizers.

scholarly journals Effect of Land Use on Organic Carbon Storage Potential of Soils with Contrasting Native Organic Matter Content

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Sabina Yeasmin ◽  
Eshara Jahan ◽  
Md. Ashik Molla ◽  
A. K. M. Mominul Islam ◽  
Md. Parvez Anwar ◽  
...  
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
Organic Carbon ◽  
Carbon Storage ◽  
Organic Matter Content ◽  
Fallow Land ◽  
Land Uses ◽  
Storage Potential ◽  
The Impact ◽  
Native Organic Matter

This study aimed to determine the impact of land use on organic carbon (OC) pools of soils with contrasting native organic matter (OM) content. Surface (0–15 cm) soils of four land uses (cropland, orchard, grassland, and fallow) were collected from four agroecological zones (AEZs) of Bangladesh with different OM content (AEZ-7: very low, −3: low, −9: medium, and −5: high). Bulk soils were physically fractionated into particulate and mineral associated OM (POM and MOM: >53 and <53 µm, respectively). Both bulk and fractionated soils were analyzed for OC and nitrogen (N). Among the land uses, undisturbed soils (grassland and fallow land) had significantly higher total OC (0.44–1.79%) than disturbed soils (orchard and cropland) (0.39–1.67%) in all AEZs. The distribution of OC and N in POM and MOM fractions was significantly different among land uses and also varied with native OM content. In all AEZs, cropland soils showed the lowest POM-C content (0.40–1.41%), whereas the orchard soils showed the highest values (0.71–1.91%). The MOM-C was highest (0.81–1.91%) in fallow land and lowest (0.53–1.51%) in orchard, and cropland had a moderate amount (0.70–1.61%). In croplands, distribution of a considerable amount of OC in the MOM pool was noticeable. These findings reveal that total OC in soils can be decreased with cultivation but does not inevitably indicate the loss of OC storage in the stable pool. Carbon storage potential of soils with both high- and low-native OM contents can be increased via proper land use and managements.

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