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The growth and reproductive potential of composting earthworm is influenced by the chemical composition of initial feed mixture. Thus the GC-MS technique is used to determine the biochemical foot prints of the vermibed substrate before composting process. The present study conducted to analyze the chemical composition of precomposted animal dung material of Elephus maximus and Bos taurus by GC-MS analysis. The dung materials were precomposted up to 14 days and used for the analysis. The GC-MS spectrogram of Elephus maximus and Bos taurus showed 20 and 15 different compounds respectively. Predominant levels of esters were observed in elephant dung, which were dominated by the esterified polyunsaturated fatty acids with maximum peak area for elaidinsaeure methyl ester (26.6%). In cow dung the maximum peak area was obtained for 1-Hydroxy-1-methyl) −2-Methyl tetrahydro −2 furanyl] − 4, 4, 14-Trimethylandrost- 9 (11) – ene −3, 6, 16 (17%) and alcohol were the dominant functional group followed by carboxylic acids and esters. Thus the results indicated that the presence of higher percentage of esterified poly unsaturated fatty acids in elephant dung reflects its higher quality suitable for vermicomposting, since the dietary unsaturated fatty acids have the positive impacts on the reproduction of earthworm by enhancing the functionality in sperm production.

Earthworms have been well reported to have a beneficial effect on soil microbes, soil microbial biomass (SMB), fungal community, soil structure, water retention and plant growth in different terrestrial ecosystems. However, the interactions between environmental stressors and various species of earthworms and the subsequent effect on soil microbes, organic matter, soil structure and plant growth are still uncertain. The purpose of this analysis was to test 1- the impact of environmental stressors on earthworm behaviour. 2- the effect of various earthworms on soil microbes, plant growth, soil structure and the carbon cycle. We noted that less fatal temperatures are generally unknown, but higher fatal temperatures range from 25 to 48 °C. Earthworms have a role to play, depending on the nature of organic residues, in both the formation and degradation of soil aggregates. Improvements in microbial biomass and plant growth have been established according to temperature, soil toxicity, soil type, earthworms abundance, organic residues types and field conditions. We observed that although the summer temperature in the arid area was approximately (°C 48), it was found that a particular type of earthworm (Namalycastis indica) was responsible for improving soil characteristics.While a great deal of analysis has been carried out on the role of earthworms within the soil ecology, such a review identifies important knowledge gaps, particularly in the determination of the impacts of earthworm species on the soil structure, microbial biomass and plant productivity, in particular since most papers focused on European species and overlooked the role of earthworms in the arid landscape. Further research is recommended to compare the impacts of different earthworms species on soil microbes and plant growth in various soil types, earthworm abundance, field conditions, organic residues locations, inorganic fertilizers, pesticides, fertile or non-fertile soils and diverse conditions of drought and moisture.

Finding strategies to reuse and treat organic wastes is of utmost need. Biological processes offer the possibility to transform them into safer end products with benefits for both agriculture and the environment. Moreover, it represents an ecologically-sound and economically attractive alternative to landfill disposal and incineration. In this work, we evaluated the feasibility of vermicomposting to treat and process grape marc, the main solid by-product of the wine industry. The long-term changes in grape marc derived from both white and red winemaking processes were assessed throughout the process of vermicomposting from a physico-chemical and microbiological perspective. New layers of fresh marc were added sequentially in the presence and absence of earthworms (Eisenia andrei) forming an age gradient during a 42-week period. An optimal moisture level of 70% was maintained over the course of the process. The pH fell within weak-alkaline levels through the layerś profile and the electrical conductivity was between 200 and 300 µS cm−1, providing optimum conditions for earthworm growth. The mass loss caused by earthworm activity led to an increased content of macro- and micronutrients at the end of the trial. An overall decrease in microbial biomass and its activity, indicative of a stabilised material, was also recorded with depth of layer. Altogether, this points to vermicomposting as a suitable management system for processing grape marc with a dual purpose, that is fertilizer production and environment protection. This is especially relevant in the current attempts to reach a fully circular economy.

A mesocosm fermentation experiment was undertaken to investigate interactions between Eisenia fetida and Collembola affecting composting processes. Earthworms, Collembola, respiration, water soluble nutrients and compost characteristics (near infrared spectra – NIRS) were monitored on four occasions over 136 days. Earthworms were the main drivers of early changes in composts, increasing the general abundance of Collembola, although responses varied with species. Earthworms accelerated substrate mineralisation and release of soluble nutrients whilst also changing compost characteristics. Collembola alone had little direct effect on soluble nutrient concentrations or respiration; they did however alter compost characteristics (NIR spectra). Earthworm-Collembola interactions affecting respiration and soluble nutrients were mainly antagonistic in the early stages of composting but synergistic in later stages. In the later stages of composting, the higher abundance of Collembola when combined with earthworms resulted in greater concentrations of soluble nitrate and phosphate. These findings emphasise the importance in vermicomposting practice of different invertebrate groups having access to feedstock at appropriate stages of the process. The high concentrations of soluble nutrients released during vermicomposting indicate the need for control measures to avoid off-site pollution and loss of this resource.

A new species of Drawida Michaelsen 1900, named Drawida ganini Zhang and Wu sp nov., is described from the material collected in the Muling River of Heilongjiang Province, Northeast China, and the adjacent region near Russia. The new species is morphologically similar to Drawida ghilarovi Gates 1969. The molecular data were more useful for comparison of D. ghilarovi samples. D. ganini is genetically different from D. ghilarovi by a p-distance value of 18.35 ± 1.37% based on the COI gene sequence data. Thus, Ganin and Atopkin's (2018) data validate taxonomical status of D. ganini as separated species.

Vermicomposting is an efficient and environmentally friendly technology to dispose of agricultural organic residues. The efficiency of organic residue decomposition during vermicomposting is directly affected by the biomass and population structure of earthworms. In this study, we investigated how the earthworm biomass and population structure responded to changes in the physicochemical properties of six types of organic residue (cattle dung, herbal waste, rice straw, soybean straw, garden waste, and tea residues) during vermicomposting. Each type of organic residues was placed in a pot with earthworms Eisenia fetida, and the physicochemical properties of the organic residues and earthworm growth dynamics were recorded at 0, 30, 60, and 90 d of vermicomposting. The biomass and population structure of earthworms were stable or increased in rice straw, garden waste, and cattle dung within 60 d of vermicomposting, whereas in tea residues and herb waste, very little earthworm activity (3 adults and 2 cocoons) was recorded on day 30. Among the physicochemical parameters, the substrate C/N ratio was negatively correlated with earthworm growth dynamics. Decomposing organic residues showed higher NH4+ -N and NO3– -N concentrations but a lower total organic carbon content, which negatively affected earthworm growth and reproduction. We recommend that chemical properties of vermicomposting systems should be monitored regularly. At the threshold levels of decomposing organic residue NH4+ -N and NO3– -N concentrations, earthworms should be removed and the vermicompost can be harvested. Small- and large-scale farmers thus need to monitor the physicochemical properties of vermicompost to sustain active earthworm populations.

Accurately quantifying the soil nitrogen (N) supply in crop fields is essential for enabling environmentally sustainable and economically profitable crop production. It requires using field-based methods to account for the contribution of soil biota, including earthworms, to N mineralization in temperate agroecosystems. The direct contribution of earthworms to the soil N cycle is the N they release throughout their life and after death, and it can be estimated using the secondary production method. This study was conducted in 2014 and 2015 in two adjacent fields with annual corn-soybean rotation in Ste-Anne-de-Bellevue, Quebec, Canada. The cumulative biomass of Aporrectodea spp. in two no-till corn-soybean agroecosystems was determined, and the direct N flux from these earthworms was estimated during the corn and soybean phases of the rotation. Secondary production was estimated by sampling earthworms biweekly during April–June and September–November and inferring the change in earthworm biomass between sampling dates using a size frequency calculation. The N flux was calculated as the sum of the N released through excretion, during periods when earthworms were active, and from mortality. The secondary production of the Aporrectodea population was estimated to be 8–43 g ash-free dry weight m–2 year–1, and the N flux was 22–105 kg N ha–1 year–1. The N flux was higher at the early vegetative growth stage, which is a period of high N demand for corn. These findings suggest that refining the N fertilization recommendation by accounting for soil N supplied by earthworms could potentially reduce fertilizer costs and environmental N losses.

Earthworms have significant effect on vegetation and soil physical and chemical properties. The relationship between earthworms and biodiversity is important in ecological researches. Therefore, the effects of earthworm on plant diversity and various indices of diversity and richness, as well as physical and chemical properties of soil in shrub, grass and bare vegetation types on exclosure and grazing sites of Miankaleh Mazandaran biosphere reserve is investigated in this work. Accordingly, sampling was carried out randomly-systematically in three different vegetative types (shrubs, grass and bare soil) at 0 to 20 cm depth. Each vegetative types was placed on three transects of 100 m, 10 plots at a distance of 30 m. Earthworm and soil were sampled from the center of each plot of 25 cm × 25 cm. The Simpson and Shannon-Wiener indexes and Margalef and Menhinick richness indices were used to evaluate diversity and richness of species at different grazing intensities. Stepwise regression was used to study the relationship between diversity and richness indices with different earthworm parameters. The results showed that there was significant difference of potassium and nitrogen in vegetation types of both exclosure and grazing sites at P ≤ .01. Furthermore, the organic carbon, organic matter and potassium in the exclosure site and nitrogen and soil moisture in the grazing site are increased by earthworm abundance.

Riparian buffers, located in the transition zone between terrestrial and aquatic ecosystems, are a hotspot for nitrogen (N) removal through denitrification. Earthworms are abundant in riparian buffers and may enhance denitrification. This study investigated earthworm demographics of three earthworm functional groups (anecic, epigeic, and endogeic) and denitrifier activity in temporarily flooded and non-flooded riparian soils from April to October 2012 in southern Quebec, Canada. Nine earthworm species, mostly endogeic, were found in the temporarily flooded soil, while only six earthworm species were found in the non-flooded soil. On average, there were 11.7 times more earthworms with 12.4 times greater biomass (P

Effects of earthworm casts on soil nutrient dynamics and their responses to changing moisture availability in subtropical ecosystems remain poorly understood. This study aimed to examine short-term carbon (C) and nitrogen (N) dynamics and their interactions with wetting-drying cycles in three different structural forms (i.e., granular, globular, and heap-like) of Amynthas earthworm casts. The rates of C and N mineralization in the earthworm casts were examined under two different wetting-drying cycles (i.e., 2-d and 4-d wetting intervals) using a rainfall simulation experiment. After three simulated rainfall events, subsamples of the earthworm casts were further incubated for 4 d for the determination of CO2 and N2O fluxes. The results of this study indicated that the impacts of wetting-drying cycles on the short-term C and N dynamics were highly variable among the three cast forms, but wetting-drying cycles significantly reduced the cumulative CO2 and N2O fluxes by 62%–83% and 57%–85%, respectively, when compared to the control without being subjected to any rainfall events. The C mineralization rates in different cast forms were affected by the amount of organic substrates and N content in casts, which were associated with the food preference and selection of earthworms. Meanwhile, the cumulative N2O fluxes did not differ among the three cast forms. Repeated wetting and drying of casts not only enhanced aggregate stability by promoting bonds between the cast particles, but also inhibited microbial survival and growth during the prolonged drying period, which together hindered decomposition and denitrification. Our findings demonstrated that the interactions between the structural forms, aggregate dynamics, and C and N cycling in the earthworm casts were highly complex.

As the dominant macrofauna in many soils, earthworms play a significant role in mineral weathering and nutrient release from mineral structures into available forms for root uptake. Phlogopite is a trioctahedral micaceous mineral that can be weathered to other minerals through release of its interlayer potassium (K). In this study, we investigated the effect of earthworm activities and associated microbial communities on phlogopite weathering during the production of phlogopite-enriched vermicompost with different quantities of phlogopite added. An experiment was run under laboratory conditions using three levels of phlogopite (0, 20% and 40% by weight) in triplicates. Each Petri dish contained 20 g of a mixture of cow manure and phlogopite, and vermicomposting process was performed by inoculation of eight Eisenia foetida earthworms. Changes in clay mineralogy and C/N ratio in each dish were assessed at days 0, 45, 90, 135, and 180 during vermicomposting. The results indicated that phlogopite was partially weathered to vermiculite and interstratified mica-vermiculite during the vermicomposting process. The rate of weathering was higher during the early stages of vermicomposting (the first 90 d). The weathering of phlogopite was influenced considerably by the activity of earthworms and associated microbial communities during the organic matter transformation process. At the early stages of the process, the weathering rate for different levels of phlogopite was not significantly different, but over time it accelerated steadily, and the difference increased.

International audience; Earthworms are widespread soil organisms that contribute to a wide range of ecosystem services. As such, it is important to improve our knowledge, still scanty, of the factors that drive the assembly of earthworm communities. The aim of the present study was to conjointly evaluate the effects on the assembly of earthworm communities of i) soil properties (texture, organic matter content, and pH), ii) grassland management (grassland age, livestock unit, and type of fertilization), iii) landscape diversity (richness, diversity of surrounding habitats, and grassland plant diversity), and iv) presence of hedgerows. The study was conducted in temperate grasslands of Brittany, France. Earthworms were sampled in 24 grasslands and, in three of these grasslands, they were sampled near a hedgerow or near a ditch (control without a hedgerow). Soil properties explained the larger portion of the variation in the earthworm community parameters compared to grassland management or landscape diversity. The increase in soil organic matter content and pH were the most favorable factors for earthworm abundance and biomass, in particular for endogeic species. Regarding grassland management, the increase in the livestock unit was the most damaging factor for earthworm communities, in particular for the anecic earthworm biomass and endogeic species richness. Surprisingly, landscape diversity negatively affected the total earthworm abundance and epigeic earthworm biomass, but it was related to an increase in the epi-anecic species. At a finer scale, we also demonstrated that the presence of hedgerows surrounding grasslands enhanced earthworm species richness, especially within the epigeic and anecic ecological categories. This study highlights that the earthworm ecological categories respond specifically to environmental filters; further studies need to be conducted to elucidate the factors that drive the assembly of earthworm communities at this ecological category level. We recommend that policymakers should act on landscape management to favor earthworm diversity in order to improve the ecosystem services they drive.

The application of decomposable organic residues such as manure and crop litter is generally beneficial to earthworms. There is an emerging interest in applying biochar, a carbonaceous product of pyrolysis, to temperate agricultural soils. The slow decomposition rate of biochar, which also contains ash and combustion byproducts, could be detrimental to earthworms. The objective of this study was to describe the earthworm populations in biochar-amended soils on a dairy farm in the St. Francis River watershed, Quebec, Canada. Earthworms were collected from replicated field plots under cereal production. Site A received three wood-based biochar types at two application rates (5 and 10 t ha-1 biochar) plus an unamended control, while Site B received wood-based biochar (7.5 t ha-1 biochar), dairy cattle slurry (10 t ha-1 manure), or a combination of the biochar and manure rates plus an unamended control. Earthworms were collected by hand sorting and formaldehyde expulsion from soil pits. Three species, Aporrectodea turgida, Aporrectodea tuberculata, and Lumbricus rubellus, were found at the sites, and Aporrectodea was the dominant genus. Biochar sources, rates, and application with dairy slurry did not affect the earthworm population, which had 52–218 individuals m-2 in 2010 and 4–96 individuals m-2 in 2011. The seasonal variation in earthworm population may be due to flooding in the spring of 2011, which apparently interfered with earthworm reproduction. The similarity in earthworm abundance and biomass in plots with and without wood-based biochar leads to the conclusion that earthworm populations are stable in biochar-amended soils in this cold, humid temperate region.

The DNA sequence database assists us with great potential in species identification because it is practical and affordable to perform. More often, the identification using molecular data helps to identify morphologically variable individuals of same species, including juvenile specimens. In case of earthworms, the classical standards of taxonomy are mainly based on genital structures, while the collection of the sexually agile worm is difficult. Hence, typical barcode marker cytochrome c oxidase subunit 1 was used to explore species richness of the study area. From taxonomic relationship, the valid identification of voucher specimens was taken into consideration for characterization. The species richness of earthworm sp. viz., Metaphire houlleti, Perionyx sp., Drawida minuta, Eudichogaster prashadi, Lennogaster pusillus, Octochaetona beatrix, and Octochaetona prashadi were recorded and analyzed. Less than 1% divergence within species was found, whereas divergence between species was greater than 15% in all cases. The phylogenetic tree(s) was constructed using the best-fitted substitution model of evolution and species delimitation by Automatic Barcode Gap Discovery, operational taxonomic units, and network analysis. The prospective and limitations of molecular taxonomy and the vital role of publicly available nucleotide sequence databases were reviewed to inventor earthworm diversity. The study shows the universality of single locus persists utopian and the use of other typical loci may strengthen earthworm diversity assessment.

This study investigated the effect of replacing fishmeal with red wigglers (Eisenia fetida) worm meal (RWWM) in the diet of Nile tilapia (Oreochromis niloticus) fingerlings. Red wigglers worms (RWW) were culture on a vegetable by-product medium, harvested and dried to obtain red wigglers worm meal. The fish (average weight ± SE: 7.70 ± 0.06 g) were fed with seven diets (30% crude protein and 7.5% crude lipid), in which fishmeal was replaced with 0%, 5%, 10%, 15%, 20%, 25%, and 30% RWWM. The fish was reared in 1000 L fiberglass tanks in a recirculating aquaculture system and were hand-fed twice daily for 90 days. At the end of the experiment, the growth, feed conversion ratio, and energy utilization improved when feeding 15% and 20% RWWM compared with the control diet (P < 0.05). Using broken line regression between growth efficiency and feed utilization, showed the optimum level of RWWM replacing FM in Nile tilapia fingerlings diet was around 21 – 22% of the diet. The whole-body crude protein and ash content were elevated in the fish fed with 10–25% RWWM, while crude lipid and energy contents were elevated in the fish fed with 5–25% RWWM compared with the control group (P < 0.05). The essential and non-essential amino acids profiles of the fish were improved by 15% and 20% RWWM compared with the control (P < 0.05). The plasma glucose was decreased by 15–20% and significantly enhanced in fish fed with 25–30% RWWM diets compared with the control (P < 0.05). The total protein, albumin and globulin increased in the fish fed 15–20% diets and decreased in fish fed the 30% RWWM (P < 0.05). Therefore, this study demonstrates that RWWM could replace 20% fishmeal in the diets of Nile tilapia fingerlings without negatively affecting fish growth and physiological performance.

Recycle and reuse are the best options to deal with water scarcity. An attempt is made to reuse greywater after giving low cost effective treatment with the help of vermifilter.A laboratory scale vegetated vermifilter system consisting of Sand Gravel Filter (SGF), and Laterite Soil Vegetated Vermifilter (LSVVF)/Laterite Soil Vegetated filter (LSVF) for the treatment of greywater was developed. The developed treatment system was evaluated for its performance by varying OLR and HRT. The removal efficiency for BOD5, TKN and P using LSVF was observed to be 50–60%, 30–50% and 30–50% respectively. The corresponding values in LSVVF were 60–80%, 40–64% and 35–68%. The earthworm plays vital role in removal of organic matter. There is no detrimental effect on earthworm survival and growth observed during study period. HRT of 3 d for the system is appropriate for reducing BOD5 to a value less than 20 mg/L for an OLR up to 145 kgBOD5/ha d. The vegetated vermifilter was found useful for the treatment of greywater. It provides a low-cost, efficient, easily operable/maintainable and least mechanized option for greywater treatment in a decentralized system. This system is suitable for rural sanitation in developing country like India.

Malting sludge is waste that could be used as a good soil conditioner after proper treatment. In the current study, the feasibility of vermicomposting malting sludge and its mixtures with straw pellets on the basis of physico-chemical and biological properties was verified. A vermicomposting system with continuous feeding of earthworms Eisenia andrei was used. The greatest number and biomass of earthworms was found in the variant with 25% malt house sludge + 75% straw pellets (on average of all layers: 320 earthworms/kg and 35 g/kg, respectively), followed by a variant with 50% malt house sludge + 50% straw pellets (on average of all layers: 47 earthworms/kg and 13 g/kg, respectively), indicating that a minimum of 50% (vol.) straw pellets is necessary for successful vermicomposting of malting sludge. Most earthworms lived in the youngest upper layer (42% and 52% of total number and earthworm biomass, respectively). On the contrary, the oldest bottom layers (final vermicomposts) after 180 days of vermicomposting were characterized by maturity, indicating lesser contents of microorganisms and enzyme activity. These vermicomposts had favorable agrochemical properties (pH = 7.8, EC = 1.2 mS cm−1, C/N = 11, Ptot = 1.23%, Ktot = 2.55%, Mgtot = 0.42%). The proportion of the available contents in the total contents were 10%, 59%, and 19% for P, K, and Mg, respectively.

Saccharum spontaenum is considered as an invasive terrestrial weed spread across the world and its management possess big challenge to the research community. The current study illustrates the potential of vermicomposting for the management of lignocellulosic terrestrial weed Saccharum spontaenum under green waste management. The vermicompost experiments were done in five different mixing ratio of Saccharum spontaenum amended with cow dung 3:7, 4:6, 5:5, 6:4, 7:3 in vermireactors referred as Ref1, Ref2, Ref3, Ref4, Ref5 respectively. The vermicomposting was carried out for total 45 days with one time feeding of the earthworms. The study indicates a mature vermicompost can be obtained with enhanced nutrients from proper mixing ratio. The different physicochemical parameters were observed to be varied among the reactors and between vermicomposting time significantly. The final C/N ratio was within 10–16 with highest decrease in Ref1. Earthworm growth was observed to be highest in Ref2 with percentage change of net biomass of earthworms with 34.25%. The highest TOC loss was observed to be 31.4% change in Ref2 and maximum TKN was 2.95% in the final vermicompost of Ref3. Even though the mixing ratio of Ref1 and Ref2 was found to be ideal for the degradation of Saccharum spontaenum, the other reactors also produced acceptable quality end product. The study further reveals that the earthworm species Eisenia fetida was highly suitable for the biodegradation of this lignocellulosic weed material.

Fenoxycarb, a juvenile hormone agonist has been widely used to control various insect pests in agriculture. Fenoxycarb has been considered environmentally safe because it degrades quickly and has lower mammalian toxicity compared with many conventional pesticides. To date, fenoxycarb is reported safe for soil organisms, but this conclusion is based solely on toxicity studies with Folsomia candida (Collembola) and Eisenia fetida (earthworm). The aim of this study was to investigate the toxic effect of fenoxycarb on Yuukianura szeptyckii (Collembola) to assess further whether this chemical is environmentally safe or not. After 28 d of exposure of fenoxycarb in the soil, adult survival and juvenile production were assessed. The median lethal concentration (LC50) value for adult was 955.2 mg/kg and the median effective concentration (EC50) and no observed effect concentration (NOEC) value for juvenile production was 0.2 mg/kg and

Background: Bisphenol A (BPA) and diisobuthylphthalate (DIBP) have found wide applications as plasticizers; however, they are covalently bonded to materials and are subsequently leached into the environment. Methods: This study evaluated the effects of BPA, DIBP and mixtures of BPA and DIBP on the antioxidant enzymes [superoxide dismutase (SOD), peroxidase (POD)] activities using standard methods and DNA profile of earthworm (Hyperiodrilus africanus) using randomly amplified polymerase chain reaction (RAPD-PCR) method. A total of 2 kg soil samples collected from FADAMA Farm, Federal University of Agriculture, Abeokuta were spiked to obtain 1, 2.5, 5 and 10 ppm of BPA, DIBP and mixtures of BPA and DIBP. Earthworms were exposed to the unpolluted and spiked soil samples and were collected on the 7th and 14th day for SOD, POD and DNA analysis. Results: SOD activity was more pronounced at 5 and 10 ppm concentrations. POD activity was increased in all concentrations, including the control, meanwhile POD activity induced by BPA and DIBP was significantly higher (p

Climate strongly influences the distribution of soil organisms in agroecosystems, but local agricultural practices can also alter the natural composition of soil communities. Conventional (CONV) practices usually cause long-term negative effects in soil agroecosystems, by reducing soil biodiversity and altering edaphic processes, while organic (ORG) practices promote soil health and the diversity and abundance of fauna. Here, we used distributional and multivariate analyses to compare the species composition and ecological structure of earthworm communities in four fruit orchards (kiwifruit, grapevine, clementine, and olive) cultivated under CONV and ORG practices and located in two different biogeographic regions of the Iberian Peninsula (Atlantic and Mediterranean). Results indicated that the interaction among the three factors studied (biogeographic region, agricultural management and fruit tree orchard) caused a significant effect on all parameters analyzed (abundance, biomass, diversity, earthworms communities, and earthworms life strategies). More earthworms were collected in Atlantic (7160 ind m−2) than Mediterranean (5576 ind m−2) region, although no differences were found between CONV and ORG practices. However, agricultural practices caused an important effect on earthworm diversity, with significant reductions in species richness (S), diversity (H′ index) and mature earthworms in the dryer and warmer climate under CONV practices. The multivariate analysis reflected those dissimilarities in ecological structure between biogeographic regions (95%) and agricultural practices (>82%). Finally, the comparison of the abundance and biomass curves confirmed that ORG practices were beneficial for earthworm populations, showing moderate or absence of ecological perturbation, and consequently, they diverted more energy to individual growth than to reproduction. Therefore, the positive effects of implementing more sustainable agricultural practices in agroecosystems will depend on their interactive effects with environmental factors, being especially useful in the dryer and warmer climates, such as in the Mediterranean region.

Tillage and stover harvest are common management practices in maize-based cropping systems around the globe. However, frequent soil disturbance and biomass export are likely to have negative long-term impacts on soil biological activity and a range of associated soil properties, and thus, there is great concern surrounding the sustainability of these practices. To address this issue, we examined soil macrofauna communities and a suite of soil chemical and physical properties in a recently established experiment (2.5 yrs. old) in Akron, Colorado. No-tillage and residue retention practices were included in a full factorial randomized block design with the following treatments: no-till + residue retention (NT/R); no-till + residue harvest (NT/RH); conventional tillage + residue retention (CT/R); and conventional tillage + residue harvest (CT/RH). In year three of the experiment, soil health parameters were assessed including: soil macrofauna diversity and abundance, aggregate stability, potential infiltration, and chemical fertility measures. The combined practice of residue retention with no-tillage (NT/R) resulted in greater macrofauna abundance, including a five-fold increase in earthworm abundance and biomass. Greater earthworm populations were associated with an increase in aggregate stability and a trend towards greater water infiltration under NT/R. While univariate tests did not reveal significant treatment differences in arthropod taxa, multivariate analyses indicated clear treatment effects on macrofauna communities, with tillage generally separating communities more than residue management. Soil chemical parameters indicated relatively less dramatic differences between treatments, but with some notable impacts of both residue retention and tillage on soil C and N dynamics. Findings from our study, among the first to examine whole soil macrofauna communities in the semi-arid Great Plains, suggest that no-till and residue retention practices offer promise for improving soil biological activity and soil structural properties of soil, especially when these two practices are employed in combination.

Earthworms naturally secrete substantial amounts of mucus (relative to their body size) from the cuticle when moving through the soil. However, how the metabolites in the epidermally derived mucus affect soil microfauna is largely unknown. The objective of this study was to determine how earthworm mucus affected the physiology of the model nematode Caenorhabditis elegans and that of two soil-dwelling bacterial-feeding nematodes: Mesorhabditis sp. and Protorhabditis sp. The traits examined included phobotaxis, reproduction, mortality, body size, feeding inhibition rate, and feeding preference. Two nematode species escaped from the earthworm mucus, whereas earthworm mucus reduced the reproduction of C. elegans and increased the mortality of C. elegans and Mesorhabditis sp. Moreover, earthworm mucus reduced the feeding rate of C. elegans and Protorhabditis sp. and changed the feeding preferences of all three species of nematodes. At 48 h, earthworm mucus increased feeding on Bacillus amyloliquefaciens JX1 for C. elegans and Protorhabditis sp. and reduced feeding on Escherichia coli OP50 for Mesorhabditis sp. These results suggest that earthworm mucus can be detrimental to bacterial-feeding nematodes and provide insights into the non-trophic interactions between earthworms and other soil biota.

Increasing applications of engineered nanomaterials lead to the release of nanoparticles into various environmental media, especially soil. However, the environmental behavior of nano ZnO in soil and the toxic mechanism to terrestrial invertebrates were not fully understood. In this study, the concentrations of nano ZnO in earthworms (Eisenia fetida) were measured to assess its bioaccumulation. The ratio of nano ZnO in earthworms to soil in 250 mg/kg treatment group was lower than that in 10 mg/kg treatment group as the earthworms would not take up too much nano ZnO to protect themselves from the damage. Combination of in-vivo and in-vitro tests was adapted to investigate the toxic mechanism of nano ZnO to earthworms. In in-vivo test, biomarkers including ROS, SOD, and MDA suggested that the toxic effects of nano ZnO to earthworms were caused by the oxidative stress. To further elucidate its toxic mechanism, in-vitro toxicity test was carried out by employing earthworm coelomocytes. The biomarkers, intracellular ROS, extracellular LDH, and cell viability showed concentration-dependent manner with nano ZnO in the culture media, demonstrating that in-vitro toxicity test could be utilized to reveal the toxic mechanism of nano ZnO to earthworms or other organisms.

The rapid development of selenium-enriched agriculture leads to the accumulation of selenium in the soil, which has an adverse impact on terrestrial ecosystems. In the present study, the mortality, growth inhibition rate and metabolism of earthworms were examined to investigate the toxicological effects of sodium selenite (Na2SeO3) on earthworms (Eisenia fetida) after exposuring for 14 days (d). We used 1H-NMR-based metabolomics to identify sensitive biomarkers and explored the metabolic responses of earthworms exposed to Na2SeO3. The mortality and growth inhibition rate of earthworms exposed to 70 and 90 mg/kg Na2SeO3 were significantly higher than the rate of control group. The LC50 (the median lethal concentration) of Na2SeO3 was 57.4 mg/kg in this artificial soil test of E. fetida exposed to Na2SeO3 for 14 d. However, there was no significant differences when earthworms were exposed to different concentrations of Na2SeO3. The selected metabolic markers were ATP, lactic acid, leucine, alanine, valine, glycine, glutamic acid, lysine, α-glucose and betaine. Na2SeO3 affected the metabolic level of earthworms, as the percentage of metabolic markers in the earthworm changes when exposed to different concentrations of Na2SeO3. The metabolic disturbances were greater with increasing concentrations of Na2SeO3. The differential metabolic markers were significantly changed when exposed to Na2SeO3 comparing to those in the control group, affecting the tricarboxylic acid cycle process and breaking the metabolic balance. This study showed that Na2SeO3 had toxic effect on the growth and development of earthworms. In addition, this study provided a biochemical insights for the development of selenium-enriched agriculture.

Tolclofos-methyl (TM) is an organophosphorus fungicide and widely utilized to control soil-borne diseases. However, toxic effects of TM on terrestrial invertebrates are still unknown. Here we measured the bioaccumulation of TM in earthworms (Eisenia fetida) to assess its environmental bioavailability. Mortality, weight change, and oxidative damage of earthworms were determined to investigate the toxicological bioavailability of TM. ROS, SOD and MDA in highest concentration treatment group significantly increased compared to the control group, suggesting that hazardous effects of TM to earthworms were caused by the oxidative stress. To further examine its toxicological bioavailability, cytotoxicity test was carried out by using extracted earthworm coelomocytes. The biomarkers, e.g., intracellular ROS, extracellular LDH, and cell viability showed correlation with TM in the culture media, demonstrating that cytotoxicity test could be employed to reflect the toxicological bioavailability of pollutants to earthworms or other organisms.

Forest ecosystems are often invaded by multiple exotic species that, when combined, may amplify negative impacts on native biodiversity and ecosystem functioning. These patterns are often determined from plot-level experiments, but it is less clear how interactions among native and exotic species vary across landscapes. Amur honeysuckle (Lonicera maackii) is an invasive understory shrub in eastern forests, observed to reduce understory plant diversity and alter litter decomposition rates. Exotic earthworms may aid this process by increasing decomposition rates and nutrient fluxes in forest soils. We hypothesized that honeysuckle increases exotic earthworm density and biomass in forest soils by providing a preferred litter resource and beneficial abiotic conditions. We established 15 transects, each 100-m long, in a stratified random design across a 245-ha deciduous forest in southwestern Ohio, USA. We measured honeysuckle shrub cover and canopy tree cover along the entire transect, and sampled earthworms and standing litter biomass at intervals along each transect. We found little evidence for Amur honeysuckle effects on earthworm density but found a strong positive effect of honeysuckle cover on earthworm biomass. We also recorded an effect of species composition of canopy trees on earthworm density and biomass. Moreover, multivariate analyses indicated a shift of earthworm community composition along an oak-elm gradient of tree species composition. Standing litter biomass was lowest in areas of high earthworm biomass and in the forest interior. Our results demonstrate that landscape-level variation in tree species composition and honeysuckle invasion drive exotic earthworm density and biomass. Our findings suggest invasion of exotic shrubs may facilitate invasion by nonnative earthworms.

Vermicomposting is a green technology used in the recycling of sewage sludge using the joint action of earthworms and microorganisms. Although tetracycline is present in abundance in sewage sludge, little attention has been given to its influence on vermicomposts. This study investigated the effects of different tetracycline concentrations (0, 100, 500 and 1000 mg/kg) on the decomposition of organic matter, microbial community and antibiotic resistance genes (ARGs) during vermicomposting of spiked sludge. The results showed that 100 mg/kg tetracycline could stimulate earthworms’ growth, accompanied by the highest humification and decomposition rates of organic matter in the sludge. The abundance of active microbial cells and diversity decreased with the increase in tetracycline concentrations. The member of Bacteroidetes dominated in the tetracycline spiked treatments, especially in the higher concentration treatments. Compared to its counterparts, the addition of tetracycline significantly increased the abundances of ARGs ( tet C, tet M, tet X, tet G and tet W) and Class 1 integron ( int -1) by 4.7–186.9 folds and 4.25 folds, respectively. The genera of Bacillus and Mycobacterium were the possible bacterial pathogen hosts of ARGs enriched in tetracycline added group. This study suggests that higher concentration of tetracycline residual can modify microbial communities and increase the dissemination risk of ARGs for final sludge vermicompost.

Three new species of the earthworm genus Amynthas Kinberg, 1867 are described from Nam Phouin, Xayabouli Province, Laos. Amynthas appelhofae sp. nov. has spermathecal pores paired in 7/8/9 at 7th setal lines 0.22–0.29 circumference apart ventrally, simple intestinal caeca, and first dorsal pores in 4/5. Amynthas feakinsi sp. nov. has spermathecal pores paired in 5/6/7 at 17th setal lines, 0.30–0.35 circumference apart ventrally, manicate intestinal caeca, and first dorsal pores in 12/13. Amynthas nathanohlfsi sp. nov. has spermathecal pores paired in 6/7–8/9 at 2nd setal lines, 0.02–0.04 circumference apart ventrally, a single broad oval male porophore, and hearts only in segments XII and XIII. Keywords: Earthworms, Laos, Megascolecidae, New species, Taxonomy

Sewage sludge contains Ag2S-NPs causing NP exposure of soil fauna when sludge is applied as soil amendment. Earthworm bioturbation is an important process affecting many soil functions. Bioturbation may be affected by the presence of Ag2S-NPs, but the earthworm activity itself may also influence the displacement of these NPs that otherwise show little transport in the soil. The aim of this study was to determine effects of Ag2S-NPs on earthworm bioturbation and effect of this bioturbation on the vertical distribution of Ag2S-NPs. Columns (12 cm) of a sandy loamy soil with and without Lumbricus rubellus were prepared with and without 10 mg Ag kg−1, applied as Ag2S-NPs in the top 2 cm of the soil, while artificial rainwater was applied at ∼1.2 mm day−1. The soil columns were sampled at three depths weekly for 28 days and leachate collected from the bottom. Total Ag measurements showed more displacement of Ag to deeper soil layers in the columns with earthworms. The application of rain only did not significantly affect Ag transport in the soil. No Ag was detected in column leachates. X-ray tomography showed that changes in macro porosity and pore size distribution as a result of bioturbation were not different between columns with and without Ag2S-NPs. Earthworm activity was therefore not affected by Ag2S-NPs at the used exposure concentration. Ag concentrations along the columns and the earthworm density allowed the calculation of the bioturbation rate. The effect on the Ag transport in the soil shows that earthworm burrowing activity is a relevant process that must be taken into account when studying the fate of nanoparticles in soils. Earthworm bioturbation plays a more important role than rainfall in the vertical transport of Ag2S-NPs in soil.

Asian earthworms in the pheretimoid group are currently invading hardwood forests in the northeastern USA. Population studies of these earthworms typically focus on life stages after hatching. However, the more cryptic part of these populations, cocoons, has largely been ignored. This paper is concentrating on cocoon abundance of two pheretimoid species through the year, and on identifying their readiness to hatch as determined by the presence of embryos that were well-advanced in their development. We wanted to know when viable cocoons were present and what their embryonic development was. We found that unhatched cocoons and ready-to-hatch embryos were present all year round. At the Horticultural Research Center of the University of Vermont, A. tokioensis cocoon abundance (mean ± standard error) varied between 1203 ± 167 m−2 in the winter and 498 ± 79 m−2 in the summer. Here A. agrestis varied between 439 ± 62 m−2 in the spring and 722 ± 70 m−2 in the fall. At another site dominated by A. agrestis, cocoon abundance varied between 753 ± 150 m−2 in the spring and 1386 ± 167 m−2 in the winter. Cocoon production was estimated at about 0.6 cocoons per worm per day. We raise the question whether cocoons have a longer-term survival function beyond overwintering of the population, akin to the function of the seed bank of annual plants.

Food waste is recognized as a global issue affecting the sustainability of the food supply chain. The unnecessary exploitation of natural resources (land, water and fossil energy) and production of greenhouse gas emissions (GHG) make the reduction of food waste a key point. In this context, the use of fruit and vegetable waste (FVW) as growth substrate for fresh earthworms to produce dried meal for feed and food purpose can be recognized as a viable solution. Therefore, the aim of this study is to evaluate the environmental impact of the bioconversion of FVW into earthworm meal to be used as new food/feed source. This is carried out by adopting the Life Cycle Assessment (LCA) method with an attributional approach and solving the multifunctionality of the system with an economic allocation between earthworms and vermicompost. The results show that the main process hotspots are the emissions of methane, dinitrogen monoxide and ammonia taking place during vermicomposting, as well as FVW transport and electricity consumed during fresh earthworm processing. Respect to the one used as feed, the dried meal with food purpose shows a higher impact due to the higher economic value and to the higher electricity consumed during freeze drying compared to the oven-drying process for feed meal production. Enhancing productivity and reducing energy consumption are necessary to improve the sustainability of earthworm meal as food/feed source.

Soil structure formation is among the most important processes in river floodplains which are strongly influenced by alluvial dynamics. In the context of river restoration projects, a better understanding of soil structure formation in habitats adjacent to the river can help to prevent damages caused by riverbank erosion. Ecosystem engineers such as pioneer herbaceous plants and earthworms likely contribute to soil structure formation even despite less favourable environmental conditions. This study aims to assess the capacity of the herbaceous perennial and native species Phalaris arundinacea and earthworm communities to promote a stable soil structure in alluvial sediments, in particular fresh alluvial deposits, in the short term. Delimited plots were set-up in a restored floodplain adjacent to the Thur River in NE Switzerland and exposed to natural alluvial dynamics for 19 months. Four treatments were replicated in a randomised complete block design: (i) plots with Phalaris arundinacea as only vegetation, (ii) plots with all vegetation constantly removed, (iii) and (iv) the earthworm community reduced by mustard treatment, otherwise as (i) and (ii), respectively. Soil structure formation was analysed at the end of the experiment using different indicators: aggregate stability, field-saturated hydraulic conductivity and the porosity calculated from X-ray CT reconstructions of freeze cores. Phalaris arundinacea was capable of improving the porosity and aggregate stability of both alluvial sediments present at the beginning of the experiment but also of sediments freshly deposited during the observation period. The latter indicates a structuring effect within only one vegetation period. Earthworm abundance was as a whole very low, most likely due to the large proportion of sand. There was a small earthworm effect on soil structure formation, and only in combination with Phalaris.arundinacea. Our findings highlight the ability of Phalaris arundinacea in efficiently structuring sandy alluvial sediments in the short term even under strong alluvial dynamics. Phalaris arundinacea can therefore play a key role in the early stage of river restoration projects. Thus, facilitating the colonisation by such native pioneer herbaceous plants is a suitable step to improve the success of river restoration projects.

Soils account for >80% and 20% of the total agricultural N2O and CO2 emissions respectively. Soil management activities that target improved soil health, such as enhancing earthworm activity, may also stimulate further emissions of CO2 and N2O. One recommended strategy for mitigating these soil emissions is biochar amendment. However greater clarity on the interaction between earthworm activity and biochar, and subsequent impact on CO2 and N2O are needed to evaluate the environmental impacts of management practice. We measured N2O and CO2 emissions from a kaolinitic Acrisol in the presence or absence of earthworms, with and without application of two different biochars in a microcosm study. The two biochars were derived from indigenous trees; Zanthoxylum gilletii and Croton megalocarpus, and were tested at three application rates of 5 Mg ha−1, 10 Mg ha−1 and 25 Mg ha−1. Emissions of CO2 and N2O increased by 26% and 72% respectively in the presence of earthworms. In microcosms with biochar and earthworms however, emissions depended on type of biochar and rate of application. With C. megalocarpus, CO2 emission increased with increasing rates of biochar application with 25 Mg ha−1 resulting in higher CO2 fluxes compared to no-biochar control (p = 0.002), while no change was observed with Z. gilletii at the same rate. Nitrous oxide emissions were suppressed at 25 Mg ha−1 for both C. megalocarpus (p = 0.009) and Z. gilletii (p = 0.011). Reduction in N2O flux was however not consistent across biochar types. No change in N2O was observed with 5 Mg ha−1 and 10 Mg ha−1of C. megalocarpus. Biochar from Z. gilletii at 5 Mg ha−1 however led to increase in N2O emissions (p

Endpoint assessment using biological systems in combination with the chemical analysis is important for evaluating the residual effect of contaminants following remediation. In this study, the level of residual toxicity of polycyclic aromatic hydrocarbons (PAHs)after 120 days of phytoremediation with five different plant species:- maize (Zea mays), Sudan grass (Sorghum sudanense), vetiver (Vetiveria zizanioides), sunflower (Helianthus annuus)and wallaby grass (Austrodanthonia sp.)has been evaluated by ecotoxicological tests such as root nodulation and leghaemoglobin assay using garden pea (Pisum sativum)and acute, chronic and genotoxicity assays using earthworm (Eisenia fetida). The phytoremediated soil exhibited lesser toxicity supporting improved root nodulation and leghaemoglobin content in P. sativum and reducing DNA damage in E. fetida when compared to contaminated soil before remediation. Also, the results of the ecotoxicological assays with the legume and earthworm performed in this study complemented the results obtained by the chemical analysis of PAHs in phytoremediated soil. Therefore, these findings provide a basis for a framework in which remediation efficacy of PAHs-contaminated sites can be evaluated effectively with simple ecotoxicological bioassays using legumes and earthworms Refereed/Peer-reviewed

As ubiquitous ecosystem engineers, earthworms play an important role in shaping the architecture and functioning of soil systems. However, there is limited knowledge on how earthworms modify the soil microbiome in relation to soil biogenic aggregates, hot-spots formed by earthworms, especially in agricultural systems. We investigated microbial communities in physical fractions and bulk soil from an arable field with consecutive rice - wheat cropping after manipulating earthworms and organic amendments for 13 years. Earthworms significantly enhanced soil aggregation by 33.4% across two consecutive cropping seasons. The assemblage of bacterial communities varied strongly between soil aggregate fractions and with earthworm presence, while the assemblage of fungal communities varied most with organic amendments and less between aggregate fractions. Structural equation modelling (SEM) suggests that besides direct effects on bacteria and fungi, earthworms affected bacteria indirectly via increasing soil aggregation (MWD), but mediated fungi via lowering pH, indicating that the role of soil aggregates in structuring soil bacterial communities override that of resource availability. In conclusion, results of our over-decade field experiment suggest that earthworms modify soil microbial communities primarily through mediating soil habitat architecture and affecting resource supply.

The toxicity of the ixodicidal carbamates ethyl-4-bromophenyl carbamate (LQM 919), ethyl-4-chlorophenyl carbamate (LQM 996) and propoxur on Eisenia foetida adults was evaluated to estimate their ecotoxic potential. The earthworm mortality and weight loss produced by the three evaluated carbamates showed a concentration-dependent effect (p 0.0001) in the contact filter paper test (CFPT). In the artificial soil test (AST), mortality increased in relation to the exposure time (p 0.0001) and the concentration (p 0.01) of the carbamates. Only the earthworms exposed in the CFPT showed morphological alterations. According to the LC

The long-term consequences of changing beech abundance by admixture of valuable broad-leaved species and its effects on nutrient cycling and soil-related processes are not sufficiently investigated. Four different forest types [i.e., beech-hornbeam-maple-alder (Fagus orientalis-Carpinus betulus-Acer velutinum-Alnus glutinosa), beech-hornbeam-maple (Fagus orientalis-Carpinus betulus-Acer velutinum), beech-hornbeam (Fagus orientalis-Carpinus betulus), and pure beech (Fagus orientalis)] in northern Iran were evaluated. Litter samples were collected via litter traps, and topsoil samples were taken and analyzed for selected properties. It was found that litter quality and turnover time improved with decreasing beech abundance. Soil pH, total N, nutrient pools (i.e., P, K, Ca, and Mg), C and N stock, fine root biomass, earthworm and nematode activities, respiration, microbial biomass N, C and N mineralization, and dissolved organic N were significantly higher under mixed beech stands. However, water content, C/N ratio, and dissolved organic C were found to be significantly higher under pure beech forest type. Greater amount of soil organic C was found under beech and beech-hornbeam-maple-alder, but the microbial biomass C was not significantly different among different forest types. The stands with higher tree diversity enhanced the level of soil qCO2 and particulate organic N. A higher value of microbial entropy was recorded under beech-hornbeam stands, whereas soil particulate organic C increased under beech and beech-hornbeam forest types. Based on the result, the abundance of beech influenced nutrient cycling via litter quality and turnover time. This led to an increase in soil fertility through the admixture of broadleaf species into beech forests.

The development of soil sustainability is linked to the improved management of soil biota, such as earthworms, and crop residues to improve soil physical structure, enhance microbial activities, and increase nutrient cycling. This study examined the impacts of maize residue (65.8C/N ratio, dry biomass 0.75 kg m−2) incorporation and earthworms (70 g Metaphire guillelmi m−2) on the resistance and resilience of soil C and N cycling to experimentally applied stresses. Field treatments were maize residue incorporation, maize residue incorporation with earthworm addition, and an unamended control. Resistance and resilience of C mineralization, ammonia oxidation, and potential denitrification were investigated over 28 days following a persistent stress of Cu (1 mg Cu soil g−1) or a transient heat stress (50 °C for 16 h). The results indicated that C mineralization was more resistant and resilient than ammonia oxidation and denitrification to either a persistent Cu or a transient heat stress. The application of maize residues significantly increased soil microbial biomass, C mineralization, ammonia oxidation and potential denitrification compared with the unamended control. Maize residues significantly improved the resistance and resilience of N processes to Cu and heat stress. The presence of earthworms significantly increased potential denitrification but had limited positive effect on functional resistance and resilience. This study suggested crop residue incorporation would strongly increase soil functional resistance and resilience to persistent and transient stresses, and thus could be a useful agricultural practice to improve soil ecosystem sustainability.

Earthworm casts are hotspots of microbial activity playing an important role in the nutrient cycling of soil ecosystems. Cast ageing can be considered an ecological succession, where copiotrophic bacteria are replaced by oligotrophic bacteria as the ratio labile/recalcitrant substrates decreases. Here we use next-generation sequencing to describe the bacterial communities (microbiome) of fresh casts (day 0) from the earthworm Aporrectodea caliginosa and how they change over time (7, 15, 30 and 60 days) under natural conditions. We also look for the main, transitional and day-specific core microbiomes of A. caliginosa casts and assessed whether bacterial communities in each ageing stage are clearly distinct in their composition or can be merged into metacommunities. Fresh cast microbiomes were mainly comprised of Bacteroidetes and Proteobacteria (62% of the total sequences) and, in a lesser extent, of Acidobacteria, Actinobacteria Chloroflexi, Planctomycetes and Verrucomicrobia (36% of the total sequences). These fresh casts were richer in amplicon sequence variants (ASVs) than soil microbiomes, which also had lower abundances of Bacteroidetes but higher abundances of other bacterial phyla. As expected, copiotrophic bacteria (Alphaproteobacteria but not Bacteroidetes) significantly (P

It is known that earthworms can increase the content of water-extractable silicon (Si) in soil, thus contributing to the availability of Si for plants. However, effects of earthworms on other Si fractions in soil, such as adsorbed Si, Si bound to SOM, Si occluded in pedogenic oxides and amorphous silica have not yet been studied. Therefore, we investigated the effects of the endogeic earthworm Octolasion cyaneum Savigny on the fractionation of Si in soils and that of the epigeic earthworm Eisenia andrei Bouche on the release of Si from model substances (quartz, wheat straw, bioopal). We quantified the amounts of Si in different soil fractions and those released from model substances before and after passage through the earthworm gut by sequential Si extraction. The amounts of Si extracted from the earthworms’ casts were generally larger than in the undigested samples. This was especially pronounced for Si bound to soil organic matter (SOM; up to 41%), and for Si in wheat straw (up to 71%) and quartz (up to 1730%). With the soils, the increase in extracted Si was pronounced for the more mobile fractions (Si bound to SOM and occluded in pedogenic oxides) at the expense of amorphous silica. The amounts of mobile and adsorbed Si (plant-available Si) in soil tended to decrease after the passage through the earthworm gut, possibly by occlusion of adsorbents in aggregates formed in the gut. Our results indicate that both mechanical weathering of ingested Si-containing particles and microbial processes, promoting aggregate formation, SOM transformation and mineral solubilization, contribute to the increased release of Si, which induced the redistribution of Si among fractions.

Alpine pastureland is increasingly abandoned, leading to shrub encroachment and to the accumulation of low-quality litter. Alpine key decomposers such as earthworms were found to feed on both low- and high-quality litter, but little is known how this might affect their life history traits. To fill this gap of knowledge, we conducted a laboratory experiment with the widespread earthworm species Lumbricus rubellus Hoffmeister, 1843. Hatchlings were provided with either of three aged litter types: grass and forb leaf litter as high-quality food sources and dwarf shrub leaves as low-quality food source. A control group was fed with aged cow dung. Biomass, days until (pre-)maturity, mortality, and reproduction rate were measured regularly to assess the impacts of food quality on earthworm development. We found pronounced impacts of food source quality on the fitness of L. rubellus. The low-quality litter led to significantly delayed development of up to 53 days, the lowest mean biomass (720 mg after 32 weeks) as well as a 50% drop of produced cocoons compared with the high-quality litter. However, the F2 generation showed the highest hatchling success in the shrub treatment. We conclude that the increased consumption of low-quality dwarf shrub litter led to negative effects on the development and reproduction of L. rubellus. Overall, this might be the main reason for declining earthworm densities in abandoned Alpine pasture soils, even though the biomass of the second generation was not significantly affected possibly due to a phenotypic variability in reproduction strategy. However, the decrease of such important decomposers and ecosystem engineers can have far reaching consequences for ecosystem processes such as litter accumulation and bioturbation and thus for the stability of Alpine soil ecosystems.

Researchers have analyzed the effects of glyphosate and glyphosate-based formulations on earthworm health. A full literature review shows negative, positive, and non-significant impacts on a suite of outcomes. Pilot studies from our lab have produced similar inconsistencies. This study aimed to determine which factors drive earthworm sensitivity to Roundup-Ready-To-Use III®, a popular herbicide. Taking cues from literature and our pilot work, we examined the effects of soil temperature, initial earthworm body mass, and the interaction between the two on a) final earthworm mass after a month of exposure to contamination and b) survival time during a stress test. We found that both earthworm responses varied with intrinsic worm characteristics (e.g. initial body mass) and environmental characteristics (e.g. soil temperature). Specifically, only initially heavy worms grown in heated soil responded to contamination, and they responded by growing significantly heavier than their uncontaminated counterparts. Worms of lighter mass and worms grown in a cooler temperature did not respond to contamination by altering final body mass. Additionally, earthworms living in unheated soil survived significantly fewer minutes during the stress test, with herbicide-exposed worms surviving the shortest number of minutes overall. Initial earthworm body mass did not affect the outcome of this test. This study shows that by varying initial body condition and soil temperature, earthworms can respond positively, negatively or not at all to exposure to a glyphosate-based formulation. Earthworm sensitivity varies with specific environmental and somatic conditions, and this may explain variation in published literature, where neither initial earthworm body mass nor soil temperature is generally considered.

In eastern North America, most Lumbricid earthworms found today above the post-Wisconsin Glacial boundary are non-indigenous, some with marked potential as invasive and ecologically disruptive species. These earthworms tend to appear as assemblages, not solitary species. Among potential explanations are successional facilitation among taxa, anthropogenic dispersal mechanisms that promote multi-species introductions, or simply shared habitat determinants that lead to accumulations through various dispersal pathways. We examined headwater streambanks in higher elevation forests of eastern New York State, and found up to 15 lumbricid earthworm species per 50 m-long reach among 14 sites divided between two montane regions, the northern Catskill Mountains and the Helderberg Plateau of eastern New York State. After pooling six surveys per site taken over two years, we found consistent differences between the two regions. Although most species (14/18) were found in both regions, their relative abundances and assortment patterns differed. Eisenoides lonnbergi and Bimastos rubidus, two native species were more prevalent in the Catskills, and represented new records for both regions. Ordination (CCA) on a set of measured environmental parameters revealed that most species were distributed along a soil pH-tree composition gradient. At the site level, clustering was strongly regional, despite a relatively small distance ( 0.30 for both regions). Furthermore, the riparian zones we surveyed are relatively dynamic settings, so the stability of these novel assemblages is uncertain. With other invasive earthworm species now spreading throughout New York State, that uncertainty may grow.

In the Pampas region of Argentina agriculture is dominated by intensive no-till (NT) soybean cropping which produce negative consequences on soil quality. A group of farmers started to use the Good Agricultural Practices (GAP) which include a higher crop rotation, use of winter cover crops and nutrient restoration. In this NT system earthworms have a significant role in soil functioning, particularly in organic matter cycling and soil structure formation. The aim of this paper was to examine the contribution of earthworm activity to the process of C incorporation and soil structure maintenance in soils with different NT variants of: NT with GAP for 30 years (NT + r30); NT with some of the GAP for 12 years (NT-r12) and NT with soybean monoculture (NTm). Also a natural grassland (NA) was sampled as a reference. Earthworm aggregates were obtained by gently separating them from surrounding soil. Fine (HOC) and coarse (POC) organic matter fractions, water-stable aggregates (WSA) and mean weight diameter (MWD) were calculated for earthworm aggregates and bulk soil. In all sites only one species (Aporrectodea caliginosa) was found, with higher density in the NA, followed by NT + r30, that had about 9 times more earthworms than NTm. The number of earthworm aggregates was higher in the NT + r30 followed by the NA, both showing differences with the other NT systems. The earthworm aggregates in NA and NT + r30 had significantly more POC than the surrounding soil (230% increase in NA and 100% NT + r30). Earthworm casts had higher values of MWD and WSA than physical soil aggregates in both NA and NT + r30 management treatments. Our results show the existence of a positive feedback loop we called earthworm-driven virtuous cycle. The increase in earthworm abundance promotes higher production of earthworm aggregates which are richer in organic matter and more water stable than the surrounding soil. This has favourable results in terms of soil quality but also increase crop yields (57% in maize and 18% in soybean), by means of biologically mediated soil processes, which is a highly desirable way to sustainability of agricultural production. Farmers, politicians and the whole society should pay more attention to soil as a key component supporting agricultural production by means of internal biological soil functioning.

Pentachloronitrobenzene (PCNB) has been widely utilized as a fungicide to control diseases. However, toxic effect data of PCNB on terrestrial invertebrate are not available till now. Herein, the earthworms (Eisenia fetida) were exposed to soil containing different levels of PCNB. Mortality, weight, accumulation, and physiological indexes of earthworms were determined on certain days. PCNB inhibited the growth of earthworms and induced a significant increase in the activity of antioxidative enzymes. ROS, SOD, and MDA of earthworms in the highest treatment group were 6.8, 4.4, and 3.8 times higher than those in the control group, respectively. In addition, earthworm coelomocytes were successfully extracted, cultured, and innovatively employed in in-vitro toxicity test to evaluate the toxic effect of PCNB. The biomarkers utilized in in-vitro toxicity test, including cell viability, intracellular ROS and extracellular LDH showed significant correlations with the PCNB in the culture media, indicating that the in-vitro toxicity test may serve as a useful tool for toxic assessment of pollutants to earthworms and other organisms.

Based on the hypothesis that urban activities can deposit chemical contaminants in soil and consequently have an impact on the vitality of key organisms of the ecosystem, the aim of the present study was to analyse genotoxicity in earthworm's coelomocytes in urban soil samples in comparison to soil samples from protected areas. Earthworms (Eisenia andrei) were exposed to soil samples for 14 days, subsequently the coelomocytes were extracted with an 10% ethanol solution and used in single cell gel electrophoresis (SCGE) assay and the micronucleus (MN) assay. The levels of copper, cadmium, lead, zinc, and arsenic were measured in monitored soil samples. Earthworms exposed to urban soils had higher levels of DNA damage, according to the results of the SCGE assay, than earthworms exposed to protected area soils. The frequency of micronuclei did not differ between the studied soil samples. There was an association between % DNA (SCGE assay) and arsenic and zinc levels. Copper, lead and zinc levels in urban soil samples exceeded the limits of legal values in Brazil. Our findings show that the genotoxicity markers we tested are sensitive to contamination and this association should be taken into account by regulatory agencies.

Earthworms provide important ecosystem services in agricultural systems. However, little is known with regards to which extent earthworms feed on soil-borne plant fungal pathogens, thereby potentially reducing pathogen infection of crops. Using a food choice arena in the laboratory, we examined (i) whether the hardened resting structures (i.e., sclerotia) of white mould (Sclerotinia sclerotiorum (Lib.) de Bary) are consumed by the earthworm Lumbricus terrestris L. (Lumbricidae) and (ii) to what extent this consumption is affected by a possible hydration of sclerotia. We found that earthworms fed on sclerotia, preferably when sclerotia were hydrated. After 13 weeks of sclerotia hydration, on average, 61.1 ± 26.0% were consumed. In field plots, we further tested the interaction between earthworms, cover crops (mustard (Sinapis alba L.), oilseed radish (Raphanus sativus subsp. oleiferus M.), oat (Avena sativa L.), grass pea (Lathyrus sativus L.)) and sclerotia. After eight months, the number of remained sclerotia was lower when earthworms had access (51 ± 19%) than when earthworm had restricted access (79 ± 11%; Sidak; P = 0.01). Oilseed radish increased earthworm abundance, however cover crops did not directly reduce sclerotia. Our findings indicate that sclerotia can be reduced by supporting cover crops that favour earthworms rather than having bare fallow.

As one type of the most widespread and long-lasting anthropogenic contaminants, microplastics have become a global environmental concern. While numerous studies have demonstrated effects of microplastics on aquatic organisms, the potential influence on terrestrial faunas is relatively less known, even though soil is a primary recipient and sink of plastics. In this study, earthworm Eisenia fetida was exposed to different levels (0, 1, 5, 10, and 20% d.w.) of polyethylene (PE, ≤300 μm) and polystyrene (PS, ≤250 μm) particles in an agricultural soil to evaluate the oxidative stress. Fluorescence imaging, after dying with Nile Red, clearly indicated the ingestion of PE and PS particles by E. fetida. Exposure to PE or PS particles at the highest rate (20%) for 14 d significantly (p 0.05) increased the activity of catalase and peroxidase and the level of lipid peroxidation, while inhibited the activity of superoxide dismutase and glutathione S-transferase in E. fetida. However, no discernible effect was detected at amendment rates ≤10% for the majority of biochemical endpoints, suggesting that microplastic-induced oxidative stress would not occur in E. fetida under most environmental conditions. The influence of microplastics on bioaccumulation of PAHs and PCBs was also evaluated in E. fetida exposed to different levels (0, 0.1, 1, 5, and 10% d.w.) of PE and PS particles. The tissue concentrations of PAHs and PCBs were reduced in the presence of microplastics at amendment rates ≥1%, suggesting that microplastics did not act as a carrier to enhance contaminant uptake. This was attributed to competitive sorption of microplastics for contaminants and the specific feeding behavior of earthworm. Biodynamic model analysis confirmed that ingestion of microplastics contributed negligibly to contaminant bioaccumulation. Findings of this study suggested that under environmentally relevant conditions, microplastics should not cause significant toxic effects to E. fetida, nor enhance its accumulation of hydrophobic contaminants.