Leaching of microplastics by preferential flow in earthworm (Lumbricus terrestris) burrows

Environmental contextMicroplastics found in soil pose several potential environmental risks. This study shows that microplastics on the soil surface can be ingested by earthworms and transported to the lower soil layers. In this way, microplastics may enter the food chain and find their way into groundwater systems, especially in cases where the water table is shallow. AbstractIn the current study, we examine how the activities of earthworms (Lumbricus terrestris) affect microplastic (MP) distribution and concentration in soil, with a focus on low density polyethylene (LDPE). We also want to determine if MPs can be flushed out with water. We used a laboratory sandy soil column (polyvinyl chloride tube) experimental set-up and tested five different treatments: (1) treatment with just soil (control) to check if the saturated conductivity (Ksat) could be impacted by MP, (2) treatment with MP, (3) treatment with MP and litter, (4) treatment with earthworms and litter as a second control for treatment 5 and (5) treatment with MPs, earthworms and litter. Each treatment consisted of eight replicates. For the treatments with MP, the concentration of MP added at the start of the experiment was 7% by weight (3.97g, polyethylene, 50% 1mm–250µm, 30% 250µm–150µm and 20% <150µm) based on 52.78g of dry litter from Populus nigra. In the treatments using earthworms, two adult earthworms, with an initial average weight of (7.14±0.26) g, were placed in each column. Results showed that LDPE particles could be introduced into the soil by the earthworms. MP particles were detected in each soil sample and within different soil layers for the earthworm treatments. Earthworms showed a tendency to transport the smaller MP particles and that the amount of MPs in size class <250μm increased in soil samples with increasing soil depth in comparison to the other size classes. After leaching, MPs were only detected in the leachate from the treatments with the earthworms, and the MP had similar size distributions as the soil samples in the 40–50cm layer of the treatment with MP, earthworms and litter. The results of this study clearly show that biogenic activities can mobilise MP transport from the surface into the soil and even be leached into drainage. It is highly likely that biogenic activities constitute a potential pathway for MPs to be transported into soil and groundwater.

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Fern spore bank at Pedregulho (Itirapina, São Paulo, Brazil)

Revista Brasileira de Biologia ◽

10.1590/s0034-71081999000100017 ◽

1999 ◽

Vol 59 (1) ◽

pp. 131-139 ◽

Cited By ~ 5

Author(s):

E. A. SIMABUKURO ◽

A. BEGOVACZ ◽

L. M. ESTEVES ◽

G. M. FELIPPE

Keyword(s):

Rainy Season ◽

Soil Depth ◽

Soil Surface ◽

Sao Paulo ◽

Dry Season ◽

Soil Samples ◽

São Paulo ◽

Gallery Forest ◽

Soil Layers ◽

Disturbed Area

This paper presents an analysis of pteridophyte spore bank the site of Pedregulho, in Itirapina, state of São Paulo, Brazil. The samples of soil were collected in February (rainy season) and August (dry season) in four localities: open cerrado, cerradão, gallery forest and a disturbed area at depths of 0-5, 5-10 and 10-15 cm. The samples were collected in duplicate. Of the duplicates, one was used for spore counting and the second one for spore germination. In the cerrado, cerradão and gallery forest soil samples the values for pteridophyte spores were similar in the rainy and dry season, but in the disturbed area the percentage of spores was higher in the rainy season than in the dry season. The number of pteridophyte spores decreased with soil depth in the rainy season in the cerrado, cerradão and disturbed area. Gametophytes were found in all samples. In general, soil collected in the cerrado, cerradão and disturbed area in the dry season presented more gametophytes than the ones collected in the rainy season. The number of gametophytes was lower in the 10-15 cm deep samples. The present results clearly show a reserve of spores in the soil of the four different sites studied in Itirapina region, in Brazil. Thus in this region turning over of soil layers and other kinds of disturbance can bring spores to the soil surface and their germination. This is one of the first reports of a pteridophyte spore bank for Brazil, no mention of any pteridophyte spore bank is made for South America by Lindsay & Dyer (1990) and Dyer & Lindsay (1992).

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DEGRADASI LAHAN PADA KEBUN CAMPURAN DAN TEGALAN DI KABUPATEN DHARMASRAYA

Jurnal Solum ◽

10.25077/js.4.1.5-9.2007 ◽

2007 ◽

Vol 4 (1) ◽

pp. 5

Author(s):

Syafrimen Yasin ◽

Gusnidar Gusnidar ◽

Dedy Iskandar

Keyword(s):

Land Use ◽

Soil Depth ◽

Soil Surface ◽

Soil Samples ◽

Imperata Cylindrica ◽

Undisturbed Soil ◽

Fertility Status ◽

Land Use Types ◽

Bulk Volume ◽

Soil Fertility Status

A research conducted in Sungai Rumbai, Dharmasraya Regency and in Soil Laboratory Andalas university was aimed to evaluate soil fertility status on the depth below 0-20 cm from several land use types , especially under Mixed Garden and annual cultivated dryland soil. Soil samples were taken on Ultisol at 0-8% slope (late-waving soil surface). Land use types evaluated were forest, annual cultivated dryland, bush land, rangeland covered by Imperata cylindrica and mixed garden. Composite soil samples for soil chemical analysis were taken on the 0-20 cm soil depth with four replications, and 5 drillings for each replication. Undisturbed soil samples by using sample ring were used to analyze sol bulk volume. The data resulted were compared to the criteria and were statistically tested using Analysis of Variance and then were continued by LSD at 5% level. From the results of analyses could be concluded that land use for mixed garden had the higher Organic Carbon (OC) content and the lower bulk volume (BV) than those for annual cultivated dryland soil.Key Words: Degradasi Lahan, Kebun Campuran, Tegalan

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Relationship between the mass of organic matter and carbon in soil

Brazilian Archives of Biology and Technology ◽

10.1590/s1516-89132008000200005 ◽

2008 ◽

Vol 51 (2) ◽

pp. 263-269 ◽

Cited By ~ 22

Author(s):

Silmara R. Bianchi ◽

Mario Miyazawa ◽

Edson L. de Oliveira ◽

Marcos Antonio Pavan

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Organic Carbon ◽

Soil Depth ◽

Soil Surface ◽

Soil Samples ◽

Loss On Ignition ◽

Oxidation Degree ◽

Wide Range

The quantity of soil organic matter (SOM) was estimated through the determination of soil organic carbon (SOC) times a factor, which assumes that 58% of the SOM was formed by carbon. A number of soil samples with wide range of SOC content collected in the state of Paraná, Brazil were evaluated in the laboratory. SOC was measured by Walkley-Black method and the total SOM by loss on ignition. The SOC was positively correlated with SOM. The SOM/SOC ratio varied from 1.91 to 5.08 for the soils. It shows that Brazilian SOM has greater oxidation degree. Although, the SOM and SOC decreased with soil depth the SOM/SOC ratio increased. It showed that SOM in the subsoil contained more oxygen but less carbon than the SOM in the upper soil surface. The CEC/SOC also increased with depth indicating that the functional groups of the SOM increased per unity of carbon.

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Effects of large macropores on soil evaporation in salt marshes

10.5194/egusphere-egu2020-1843 ◽

2020 ◽

Author(s):

Tingzhang Zhou ◽

Pei Xin ◽

Jirka Jirka Šimůnek

Keyword(s):

Water Flow ◽

Salt Marshes ◽

Evaporation Rate ◽

Preferential Flow ◽

Soil Surface ◽

Soil Evaporation ◽

Infrared Light ◽

Soil Conditions ◽

Set Up ◽

The Impact

<p>The occurrence of macropores in salt marsh sediments is a natural and ubiquitous phenomenon. Although they are widely assumed to significantly affect water flow in salt marshes, the effects are not well understood. We conducted physical laboratory experiments and numerical simulations to examine the impact of macropores on soil evaporation. Soil columns packed with either sand or clay and with or without macropores were set up with water tables in the columns set at different levels. A high potential evaporation rate was induced by infrared light and a fan. The results showed that in the soil with a low saturated hydraulic conductivity (and thus a low transport capacity), macropores behaved as preferential flow paths, delivering water from the groundwater towards the soil surface and maintaining a high evaporation rate in comparison with the soil without macropores. This effect was more pronounced for sediments with lower hydraulic conductivities and shallower groundwater tables. These results not only improve our understanding of water flow and soil conditions in salt marshes but also shed light on soil evaporation in other hydrological systems.</p>

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Leaching Potential of Some Omani Soils: Soil Column and Drip Irrigation Studies

Journal of Agricultural and Marine Sciences [JAMS] ◽

10.24200/jams.vol4iss2pp65-70 ◽

1999 ◽

Vol 4 (2) ◽

pp. 65

Author(s):

M. Ahmed ◽

S.A. AI-Rawahy ◽

M.S. AI-Kalbani ◽

J.K. AI-Handaly

Keyword(s):

Drip Irrigation ◽

Soil Profile ◽

Laboratory Experiments ◽

Soil Column ◽

Soil Surface ◽

Soil Samples ◽

Soil Columns ◽

Leaching Potential ◽

Marked Accumulation ◽

Leaching Experiments

This paper reports the findings from leaching experiments conducted on some Omani soils. Seven samples from two locations in the Batinah coastal area of Oman were analyzed. Repacked soil columns of up to 30 cm in length were used in laboratory experiments to estimate the amount of water required for adequate leaching of salts from the soil profile. Two methods of leaching: continuous ponding and intermittent ponding were investigated. Results show that most of the salt (50-90%) is removed from the soil profile by the application of water equal in amount to the depth of soil to be leached. The results also show that intermittent ponding method of leaching is more efficient than the continuous ponding method of leaching if initial salinity level is high. Soil samples were also collected to find out the salinity status under drip irrigation. It clearly demonstrates that drip irrigation is very effective in removing salts from soil near the emitters although there is a marked accumulation of salts on the soil surface between emitters.

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Simulating future salinity dynamics in a coastal marshland under different climate scenarios

10.5194/hess-2018-597 ◽

2019 ◽

Author(s):

Julius Eberhard ◽

N. Loes M. B. van Schaik ◽

Anett Schibalski ◽

Thomas Gräff

Keyword(s):

Greenhouse Gas Emission ◽

Soil Column ◽

Soil Surface ◽

Unconfined Aquifer ◽

Salt Transport ◽

Winter Rainfall ◽

Deep Aquifer ◽

Groundwater Levels ◽

Set Up ◽

The One

Abstract. Salinization is a well-known problem in agricultural areas worldwide. For the last 20–30 years, rising salinity in the upper, unconfined aquifer has been observed in the Freepsumer Meer, a deep grassland area near the German North Sea coast. In order to investigate long-term development of soil salinity and water balance, the one-dimensional SWAP model was set up and calibrated for a soil column in the area, simulating water and salt balance at discrete depths for 1961–2099. The model setup involved a deep aquifer as the only source of salt through upward seepage since other sources were negligible. In the vertical salt transport equation, only dispersion and advection were included. Six different regional outputs of statistical downscaling methods (WETTREG, XDS), based on simulations of different GCMs (ECHAM5, ECHAM6, IPSL-CM5) driven by greenhouse gas emission scenarios (SRES-A2, SRES-B1) and concentration pathways (RCP45, RCP85), were used as scenarios. These comprised different rates of increasing surface temperature and essentially different trends in seasonal rainfall. The results of the model runs exhibit opposing salinity trends for topsoil and deeper layers: While the projections of some scenarios entail decreasing salinities near the soil surface, most of them project a rise in subsoil salinity with strongest trends of up to +0.9 mg cm−3 (100 a)−1 at −65 cm. The results suggest that topsoil salinity trends are affected by the magnitude of winter rainfall trends while high subsoil salinity trends correspond to low winter rainfall and high summer temperature. Absolute salinity is high in scenarios of high-temperature and low-rainfall summers. How these projected trends affect the vegetation and thereby future land use will depend on the future management of groundwater levels in the area.

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Soybean Root Growth in Response to Chemical, Physical, and Biological Soil Variations

Frontiers in Plant Science ◽

10.3389/fpls.2021.602569 ◽

2021 ◽

Vol 12 ◽

Author(s):

Mariele Müller ◽

Julia Renata Schneider ◽

Vilson Antônio Klein ◽

Eliardo da Silva ◽

José Pereira da Silva Júnior ◽

...

Keyword(s):

Microbial Biomass ◽

Root Growth ◽

Negative Impact ◽

Soil Depth ◽

Soil Surface ◽

Total Porosity ◽

Soil Layers ◽

Soybean Roots ◽

Biological Attributes ◽

High Concentrations

Environmental conditions affect crop yield, and water deficit has been highlighted by the negative impact on soybean grain production. Radicial growth in greater volume and depth can be an alternative to minimize losses caused by a lack of water. Therefore, knowledge of how soybean roots behave before the chemical, physical, and biological attributes of the soil can help establish managements that benefit in-depth root growth. The objective was to evaluate the growth of soybean roots in response to chemical, physical, and biological variations in the soil, in different soil locations and depths. Six experiments were conducted in different locations. Soil samples were collected every 5 cm of soil up to 60 cm of soil depth for chemical, physical, and biological analysis. The roots were collected every 5 cm deep up to 45 cm deep from the ground. The six sites presented unsatisfactory values of pH and organic matter, and presented phosphorus, potassium, and calcium at high concentrations in the first centimeters of soil depth. The total porosity of the soil was above 0.50 m3 m−3, but the proportion of the volume of macropores, micropores, and cryptopores resulted in soils with resistance to penetration to the roots. Microbial biomass was higher on the soil surface when compared to deeper soil layers, however, the metabolic quotient was higher in soil depth, showing that microorganisms in depth have low ability to incorporate carbon into microbial biomass. Root growth occurred in a greater proportion in the first centimeters of soil-depth, possibly because the soil attributes that favor the root growth is concentrated on the soil surface.

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Water retention in a peatland with organic matter in different decomposition stages

Revista Brasileira de Ciência do Solo ◽

10.1590/s0100-06832011000400015 ◽

2011 ◽

Vol 35 (4) ◽

pp. 1217-1227 ◽

Cited By ~ 16

Author(s):

José Ricardo da Rocha Campos ◽

Alexandre Christófaro Silva ◽

José Sebastião Cunha Fernandes ◽

Mozart Martins Ferreira ◽

Daniel Valladão Silva

Keyword(s):

Organic Matter ◽

Water Retention ◽

Soil Depth ◽

Soil Column ◽

Soil Surface ◽

Intermediate Stage ◽

Standard Procedures ◽

Decomposition Of Organic Matter ◽

Advanced Stages ◽

Maximum Water

Peatlands are ecosystems formed by successive pedogenetic processes, resulting in progressive accumulation of plant remains in the soil column under conditions that inhibit the activity of most microbial decomposers. In Diamantina, state of Minas Gerais, Brazil, a peatland is located at 1366 m asl, in a region with a quartz-rich lithology and characteristic wet grassland vegetation. For this study, the peat area was divided in 12 transects, from which a total of 90 soil samples were collected at a distance of 20 m from each other. The properties rubbed fiber content (RF), bulk density (Bd), mineral material (MM), organic matter (OM), moisture (Moi) and maximum water holding capacity (MWHC) were analyzed in all samples. From three selected profiles of this whole area, samples were collected every 27 cm from the soil surface down to a depth of 216 cm. In these samples, moisture was additionally determined at a pressure of 10 kPa (Moi10) or 1500 kPa (Moi1500), using Richards' extractor and soil organic matter was fractionated by standard procedures. The OM decomposition stage of this peat was found to increase with soil depth. Moi and MWHC were highest in layers with less advanced stages of OM decomposition. The humin levels were highest in layers in earlier stages of OM decomposition and with higher levels of water retention at MWHC and Moi10. Humic acid contents were higher in layers at an intermediate stage of decomposition of organic matter and with lowest levels of water retention at MWHC, Moi10 and Moi1500.

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Does <i>Juncus effusus</i> enhance methane emissions from grazed pastures on peat?

Biogeosciences Discussions ◽

10.5194/bgd-12-8467-2015 ◽

2015 ◽

Vol 12 (11) ◽

pp. 8467-8495 ◽

Cited By ~ 2

Author(s):

A. Henneberg ◽

L. Elsgaard ◽

B. K. Sorrell ◽

H. Brix ◽

S. O. Petersen

Keyword(s):

Soil Column ◽

Soil Surface ◽

Point Sources ◽

Organic Soils ◽

Juncus Effusus ◽

Emission Rates ◽

Soil Layers ◽

Local Maxima ◽

Ch4 Emissions ◽

Field Campaigns

Abstract. Methane (CH4) emissions from drained organic soils are generally low, but internal gas transport in aerenchymatous plants may result in local emission hotspots. In a paired-sample field study at three different sites we measured fluxes of CH4 with static chambers from adjacent sampling quadrats with and without Juncus effusus during four field campaigns. At all three sites, CH4 was observed in the soil at all sampling depths (5–100 cm), and in most cases both above and below the groundwater table. During spring, local maxima suggested methanogenesis took place above the water table at all three sites. We found significant CH4 emissions at all three sites, but emission controls were clearly different. Across the three sites, average emission rates (±1 SE) for sampling quadrats with and without J. effusus were 1.47 ± 0.28 and 1.37 ± 0.33 mg CH4 m-2 h-1 respectively, with no overall effect of J. effusus on CH4 emissions, but a significant effect at one of the three sites. At this site, local CH4 maxima were closer to the soil surface than at the other sites, and the upper soil layers were dryer. This could have affected both root CH4 accessibility and CH4 oxidation respectively, and together with limited gas diffusivity in the soil column, cause elevated CH4 emissions from J. effusus. We conclude that aerenchymatous plants has the potential to act as point sources of CH4 from drained peatlands, but more studies on the specific conditions under which there is an effect, are needed before the results can be used in modelling of CH4 emissions.

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Estimation of Iodine Leaching in Soil Amended with Organic and Inorganic Materials Using HYDRUS 1-D Model

Sustainability ◽

10.3390/su131910967 ◽

2021 ◽

Vol 13 (19) ◽

pp. 10967

Author(s):

Muhammad Mohiuddin ◽

Jawad Ali ◽

Megersa Kebede Leta ◽

Muhammad Waseem ◽

Muhammad Irshad ◽

...

Keyword(s):

Preferential Flow ◽

Soil Depth ◽

Soil Column ◽

Freundlich Isotherm ◽

Iodine Content ◽

Inorganic Materials ◽

Soil Columns ◽

Column Studies ◽

1D Model ◽

Hydrus 1D

This study investigated the ability of a HYDRUS 1D model for predicting the vertical distribution of potassium iodine (200 ppm) in soil columns after amendment with five different common remediation materials (gypsum, lime, fly ash, charcoal, and sawdust) at a rate of 2.5% (w/w), relative to an unamended control soil. Results showed that relative to the unamended soil, iodine leaching was decreased by all amendments but that the magnitude of the decreases varied with the soil amendment applied. Iodine content was highest in the upper layer of the soil columns and decreased progressively with soil depth. The model was evaluated via comparison of the model simulated values with measured values from the soil column studies. The results showed that the HYDRUS 1D model efficiency was near to 1, indicating the stimulated results near to the measured values. Therefore, this study showed that iodine leaching through a soil could be ascertained well using a HYDRUS 1D model. The model over predicted iodine leaching, results in a weak correspondence between the simulated and the measured results for iodine leaching. This suggests that the HYDRUS-1D model does not explain accurately different organic and inorganic amended soil and the preferential flow that occurs in these columns. This may be due to the fact that Freundlich isotherm, which is part of the transport equations, does not sufficiently describe the mechanism of iodine adsorption onto the soil particles. This study would help to select an amendment for an effective management strategy to reduce exogenous iodine losses from agro-ecosystems. This would also improve scientific understanding of iodine transport in soil profile.

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