Earthworm Biomass Research Articles

Earthworm diversity and community assemblage: influencing factors at plot-scale in urban areas

Soil fauna including earthworms play a crucial role in various ecosystem functions, thereby contributing to human well-being. The relationships between earthworm populations and environmental factors have frequently been established at regional scales, particularly in urban soils. However, the diversity and community assemblage of earthworms, as well as their influencing mechanism at plot scale, have rarely been studied. Based on the earthworm assemblage from 29 sites in 12 residential communities, the average earthworm abundance, biomass, and species richness were 59.0 individuals/m2, 21.7 ​g/m2, and 1.59 species, respectively. Based on a generalized linear mixed model, vegetation distribution pattern, vegetative cover type, and surrounding built environment all affected earthworm biomass. However, none of these residential variables significantly affected its community assemblage. Variation partitioning in canonical ordination revealed that edaphic properties, rather than landscapes, played a significant role in explaining the variation in its community assemblage, with an approximate contribution of 23%. The abundance and biomass of earthworms at the plot-scale in this study were consistent with previous studies at regional scales. However, the species richness at plot scale was lower than those at regional scale, suggesting that earthworm biodiversity may not accurately represent that at a larger scale, species-area relationship. The results indicate a shift in the driving factors of earthworm community assemblage from edaphic property variation at the plot scale to edaphic, historical, and biogeographical heterogeneities at the regional scale. Certain species that are sensitive to key edaphic/landscape parameters are potential candidates for monitoring soil ecological health.

Status of Soil Health Indicators after 18 Years of Systematic Tillage in a Long-Term Experiment

Long-term cultivation experiments are gaining more attention due to the possibility of following the changes in soil parameters (e.g., soil organic carbon (SOC), stock and soil health indicators, etc.). Our objective was to assess the status of soil in an 18-year-old tillage experiment after almost two decades of systematic tillage. In this research, soil physical (bulk density, moisture content), chemical (pH, SOC), and biological properties (soil microbial respiration, abundance, biomass, species composition of earthworms, yield) were used as indicators in three soil cultivation methods representing different degrees of disturbance (no-till—NT; shallow cultivation—SC; and ploughing—P). Based on our results, there were significant differences in bulk density (NT > SC, P) in 0–10 cm, and NT > P in deeper layers (10–20, 20–30, 30–40 cm), while the SOC content in 0–10 cm was the highest in NT (2.5%), followed by SC (2.4%) and P (2.0%). Soil microbial respiration was significantly greater in NT than in SC and P. The abundance and biomass of earthworms was the highest in NT (189 ind m−2, 41.26 g m−2), followed by SC (125 ind m−2, 36.9 g m−2) and P (48 ind m−2, 7.4 g m−2). We concluded that NT offered a beneficial habitat for earthworms and microorganisms and a high SOC storage capacity; however, bulk density was less convenient due to soil compaction in our experiment. Therefore, SC can be used as an alternative approach for sustainable soil tillage.

Root-derived resources fuel earthworms predominantly via bacterial and plant energy channels – Insights from bulk and compound-specific isotope analyses

Soil food webs rely on both brown and green energy, i.e., litter material and root-derived resources such as exudates. Earthworms have traditionally been viewed as macro-detritivores fuelled by brown energy and playing a central role in nutrient cycling and belowground energy flux. However, the role of root-derived resources for earthworm nutrition remains controversial. We studied the dietary contribution of root-derived resources from different plant functional groups to earthworms using bulk and compound-specific stable isotope analyses in a microcosm experiment with five earthworm species, grasses and legumes in monoculture and mixture, and an unplanted control by preventing leaf litter from entering the microcosms. The presence of plants consistently depleted bulk 13C values of the five earthworm species studied suggesting that root-derived carbon contributed to earthworm nutrition in each of the species. The response of bulk 15N values was less consistent, which is in line with the assumption that root-derived resources fuel soil food webs mainly via carbon-based root exudates. These observations were corroborated by 13C values of essential amino acids suggesting that most of the tissue carbon of earthworms was incorporated via bacterial- (∼60%) and plant-derived resources (∼30%), with the presence of legumes enhancing the incorporation via plant-derived resources. The high proportion of bacterial resources in the earthworms was consistent with the relative dominance of bacteria in the experimental soil and suggests that bacteria serve as important link in the acquisition of food resources. However, it remains an open question whether earthworms feed directly on soil bacteria, bacterial residues in soil or rely on nutritional supplementation by gut microorganisms. Overall, our results show that when root-derived resources are available, earthworms, as macro-detritivores, also incorporate green energy, with these resources being assimilated mainly via the bacterial energy channel, pointing to the importance of bacterial energy channelling in ecosystems with high earthworm biomass.

Testing the impacts of invasive jumping worms at their northern range limit

Earthworms can act as ecosystem engineers by altering soil structure, which impacts other organisms and ecosystem functioning. Jumping worms (family Megascolecidae) originating in Asia have been spreading in North America, extending their northern range limits to Ontario, Canada in the last decade and to New Brunswick in 2021. At the northern limits of their current range, little research has been done to examine the effects of jumping worms in these new habitats since their recent establishment. Our objectives were to evaluate: (1) how jumping worms impact soil nitrogen and soil carbon; (2) how their presence impacts the abundance of non-native European earthworms (family Lumbricidae); and (3) whether two sampling methods (i.e., mustard solution and wooden discs) are equally effective at detecting jumping worms. We sampled a residential property in Oromocto, New Brunswick, which was the first location where jumping worms were found in the province. Jumping worms did not have significant impacts on the abundance and biomass of European earthworms or soil carbon content in the top 5 cm of the soil, but they did significantly affect soil nitrogen levels. Both sampling methods were equally effective at detecting the presence of jumping worms. Further research is needed in managed landscapes, urban areas, and forests to determine the ecosystem impacts and invasion dynamics of jumping worms in Canada as this invasion progresses.

Management of grassland: A necessary tool to maintain plant and earthworm diversity

In temperate grassland, earthworms contribute to the major soil processes which determine most of the ecosystem services. The characteristics of plant communities in grassland are key factors in maintaining earthworm communities, however effects of different herbage management on earthworms remain largely unknown. In this context, the aim of the present study was to determine the long-term effects of herbage management on grassland plant and earthworm communities. Plants and earthworms were sampled in a 14-years-old experiment in upland grasslands (Massif central, France). Abandoned grasslands were compared with mowed grasslands and with pastures grazed by cattle (at low or high intensities) or grazed by sheep (at low intensity). Compared to abandoned grassland, herbage management by grazing or by mowing display higher leguminous plant, community-weighted mean Ellenberg light values as well as plant richness while they display lower percentage of plant litter and community-weighted mean Ellenberg nitrogen values. The differences in plant richness were associated with a significant change in plant community structure. Compared to the abandoned grassland, herbage management by grazing or mowing significantly display higher earthworm biomass and total richness. Except for pastures grazed by cattle at high intensity, earthworm abundance was at least twice that in the grassland at low grazing intensity or mowing compared to the abandoned grassland. Earthworm communities were significantly different between grazed and mown treatments notably due to changes within Aporrectodea anecic and endogeic earthworm species. Overall, herbage management by animals or by mechanical export is beneficial for plant and earthworm diversity although no clear differences between management practices for earthworm richness, total biomass or total abundance were observed. Our results highlight that abandonment does not preserve biodiversity (plant, soil macrofauna) while management of grassland by grazing or mowing is a necessary tool for biodiversity conservation and improvement.

Heat pre-treatment as an initial step in vermicomposting significantly influences worm population and cocoon production

Heat treatment of vermicompost and cow manure is mandated before their use as fertilizers to address the risk of pathogenicity in vermicompost derived from cow manure. While vermicomposting under mesophilic conditions does not significantly reduce microorganisms or degrade enzymes and proteins, organic matter passing through the earthworm's digestive system is effectively composted and sterilized. This study focused on cow manure and subjected it to three heat treatments: 25 °C (HT1), 70 °C for 1 hour (HT2), and 121 °C at 1.5 atm for 15 minutes (HT3). We assessed these treatments over five incubation periods (0, 7, 15, 30, and 45 days) on earthworm (Eisenia fetida L.) biomass, juvenile counts, and cocoon production. The results showed that all earthworms in HT3 died at the second incubation, while the HT1 and HT2 groups survived. Cocoon counts in HT1 and HT2 increased with each period (P<0.01). Remarkably, the number of cocoons in the control group exceeded that of the HT2 group throughout the study (P<0.01), highlighting the significant impact of heat treatment on vermicompost quality and earthworm productivity. Earthworm productivity was significantly affected by the carbon-to-nitrogen ratio (C/N), organic carbon (%), total nitrogen (%), NH4⁺-N, and NO3⁻-N. Elevated NH4⁺-N from heat treatments had a negative effect on earthworm activity.

A biological insight of hops wastes vermicomposting by Eisenia Andrei

AbstractThe study was conducted to assess the feasibility of using Eisenia andrei earthworms for vermicomposting hop remains from a lupulin extraction enterprises for the brewing industry. Vermicomposting process was conducted within 70 days using hop (Humulus lupulus) wastes blended with horse manure at five different ratios for triplicate in laboratory conditions. Number of worms, cocoons, and hatchlings were observed and recorded weekly as earthworm biomass, population build-up and reproduction biological parameters. The results showed an indirect relationship between the hop content and the growth and reproductive performance of the worms. Notwithstanding this fact, 100% of survival occurred in all combinations. A 50% blend of hop wastes and horse manure is suggested to ensure the optimizing usefulness of E. andrei. In addition, moment of maximum splendour of worm population build-up and reproduction parameters measured was achieved at around 40 or 50 days since the beginning of the test, seeing a clear and widespread decline from that moment.

Positioning earthworms in the future foods debate: a systematic review of earthworm nutritional composition in comparison to edible insects

Abstract Sustainable food system innovations are urgently needed to feed a growing human population while staying within planetary boundaries. Farmed edible insects have received considerable scientific and public attention due to their potential to improve food system circularity by upcycling nutrients from organic residual streams to nutritious food. Earthworms, as non-insect invertebrates, have remained largely unrecognized in the future foods debate. However, they are already widely farmed at industrial scale for their capacity to recycle organic wastes and improve soil fertility. We conducted a systematic literature review to provide a quantitative basis on earthworm nutritional composition, thereby positioning earthworms in the future foods debate. Here we show, based on evidence from 142 scientific studies, that farmed earthworms are a potentially interesting food source. They have an attractive nutrient composition compared to the main farmed edible insect species, being especially rich in protein, low in fat and containing a favourable profile of essential amino acids. The content of important fatty acids, minerals and vitamins in earthworm biomass is higher or lower than in edible insects, depending on the feed material. Crude protein and fat contents are higher in farmed versus wild earthworms, indicating that farming conditions provide a lever for further improving the nutritional composition of earthworm biomass. Whether earthworm species or feed materials affect earthworm nutritional composition could not be finally clarified based on the available data. We conclude that earthworms have high potential as a future food from a nutritional perspective, mainly as an alternative source of protein. The integration of earthworm farming in future food systems can be expected to improve sustainability and circularity, potentially giving earthworms an advantage over edible insects.

Earthworm population and Community structure with reference to Soil ecological parameters from different agroecosystem in Cuddalore district, Tamil Nadu, India

Earthworms are fundamental to the dynamics of our ecosystems. The six species of earthworms (Pondoscolex corethrurus (Muller, 1856), Perionyx ceylanensis (Michaelsen, 1904), Perionyx excavates (Perrier, 1872), Lambitomauritti (Kinberg, 1867), Amynthas gracilis (Kinberg, 1867) and Drawida willsi (Michaelsen, 1907)) belonging to three families (Glossoscolecidae, Megascolecidae, Moniligastridae), five Genera (Pondoscolex, Perionyx, Lambito, Amynthas, Drawida) and three orders (Opisthopora, Heplotaxida, Moniligastrida) were identified from the study site in Cuddalore district, Tamil Nadu, India.Selected two types of cultivated lands in present study: Wet Lands (Paddy, Banana, Sugarcane), Dry Lands (Coconut, Groundnut, Oil palm).Totally six species find in the study sites, two species (Perionyx excavates, Perionyx ceylanensis) were epigeic category, one species (Pondoscolex corethrurus) were endogeic category, one species (Lambito mauritti) anecic category, one species (Amynthas gracilis) were epiendogeic and last one species (Drawida willsi) were epianecic category. The wet land cultivable fieldshave three types of earthworm category (epigeic, endogeic, epianecic) and cultivable dry land fields have two types of earthworm category (anecic and epiendogeic).The statistical analysis of data was also performed by using ANOVA software and different types of soil ecological parameters (pH, moisture, temperature, organic carbon, nitrogen, phosphorous, potassium, C:N ratio, microbial activity, earthworm density, earthworm biomass, relative density, frequency, richness index, diversity index, dominance index, evenness index, Lm/Oratioa, Pe/O ratiob).

Integrated microbiota and multi-omics analysis reveal the differential responses of earthworm to conventional and biodegradable microplastics in soil under biogas slurry irrigation

As one of the promising alternatives of conventional plastic mulching film (C-PMF), biodegradable plastic mulching films (B-PMF) were employed in agronomy production to alleviate the environmental burden of C-PMF. However, information regarding the potential toxicity effects of biodegradable microplastics (MPs) in soil still in scarcity, and the available findings were found to be controversial. Additionally, little is known about the molecular toxicity effects of conventional and biodegradable MPs on terrestrial organisms. Thus, 5 % (w/w) biodegradable (polylactic acid, PLA) and conventional (polyvinylchloride, PVC; low-density polyvinylchloride, LDPE) MPs were employed to assess the toxicity effects on Eisenia fetida in agricultural soil with biogas slurry irrigation. In the present study, transcriptomic, metabolomic profiles and individual indexes were selected to reveal the toxicity mechanisms from molecular level to the individual response. Furthermore, dysbiosis of bacterial community in gut was also investigated for obtaining comprehensive knowledge on the MPs toxicity. At the end of the exposure, the number of survival earthworms after MPs exposure was significantly reduced. Compared with the initial body weight, PLA and LDPE increased the biomass of earthworms after MPs exposure, while no significant influence on the biomass was observed in PVC treatment. Microbacterium, Klebsiella and Chryseobacterium were significantly enriched in earthworm gut after PLA, PVC and LDPE exposure, respectively (p < 0.05). Transcriptomic and metabolomic analysis revealed that PLA exposure induced neurotransmission disorder and high energetic expenditure in earthworms. However, PVC and LDPE inhibited the nutrient absorption efficiency and activated the innate immunity responses of earthworms. The PLS-SEM results showed that the effects of MPs were dominated by the polymer types, and hence, significantly and directly influence the gut bacterial community of earthworms. This study provides a better understanding of the similarities and discrepancies in toxicity effects of biodegradable and conventional MPs from the perspectives of individual, gut bacterial community, transcriptome and metabolome.

Synergistic Interactions in Enzyme Activities During Vermiremediation of Heavy Metals (HMs) Polluted Soil: Elucidating the Impact of Eudrilus eugeniae

ABSTRACT The vermiremediation potential of Eudrilus eugeniae was assessed in heavy metals (HMs) contaminated soil in a microcosm experiment. In detail, efficacy of E. eugeniae was investigated in terms of reduction in HMs content, enhancement in the soil enzyme activities, synergistic correlation between the HMs and enzyme activities and bioaccumulation of HMs in the earthworm’s biomass. Moreover, a seed germination assay was also conducted to assess the HMs toxicity in soil after remediation. The results showed that Eudrilus eugeniae was capable of decreasing the Cu, Zn, Mn, Cr, and Ni contents in the soil by 17.56–26.30% after 90 days of experimental trial. Introduction of E. eugeniae increased cellulase, amylase, polyphenol oxidase, peroxidase, urease, dehydrogenase, and catalase activities by 30.3–80.95% compared to controls. Earthworm addition led to a 12.98% increase in G-Mean and 2.89% increase in T-QSI values, indicating significant soil health improvement. PCA revealed the negative impact of HMs on synergistic enzyme activities during vermiremediation. HMs content in earthworm biomass increased 13-fold. Seed germination assay confirmed HMs reduction by the end of the experiment. Thus, this study demonstrated the interconnected changes in the soil enzyme activities during vermiremediation of HMs from crude oil polluted soil.

Potential ecotoxicological effects of silver nanoparticles and silver sulphide on the endogeic earthworm Aporrectodea caliginosa (Savigny 1826)

Silver nanoparticles (AgNPs) are increasingly used in consumer products and subsequently arrive in wastewater systems, accumulating as silver sulphide (Ag2S) in the resulting biosolids, which are commonly spread onto agricultural fields as a fertiliser. Experiments were performed to investigate the effect of AgNPs, using the endogeic earthworm Aporrectodea caliginosa as a test organism. In an acute toxicity experiment, A. caliginosa were exposed to soil containing different concentrations of AgNPs (0, 1, 5, 10, 50, 100, 250, 500, 750, and 1000 mg kg−1 dry soil) and Ag2S (0, 10, 50, 100, 500, and 1000 mg kg−1 dry soil). Earthworm biomass and mortality were monitored. Earthworms exposed to 500, 750 and 1000 mg kg−1 fresh AgNPs had mortality rates of 20%, 60% and 70%, respectively. Changes in biomass were directly related to AgNP concentration. Exposure to Ag2S did not affect biomass or mortality. Further experiments used 0, 10, 50, 100 and 250 mg kg−1 AgNPs and 0, 50, 100, 500, and 1000 mg kg−1 Ag2S to evaluate sublethal effects on A. caliginosa. Avoidance behaviour in a linear gradient was evaluated after 14 days. Earthworms significantly preferred soil that was free of either AgNPs or Ag2S. The same concentrations were used to assess effects on cocoon production of A. caliginosa exposed to AgNPs and Ag2S. In the first 3 months of AgNP exposure, higher concentrations had a negative effect on cocoon production, but this effect diminished thereafter. Ag2S had no discernible effect on reproduction. Overall, introduction of AgNPs into the soil through the application of biosolids appears to be of low concern to the tested endogeic earthworm.

Production of Eudrilus eugenia and Compost From Breeding Manure (Cattle, Cavies, Rabbits, And Poultry) In South Of Côte D’ivoire

Developing countries must, in order to support agriculture, integrate available natural resources and promote management of livestock waste. Therefore, the potential of earthworms to decompose organic waste must be exploit : vermicomposting. Thus earthworm Eudrilus eugeniae was cultured in 4 simples treatments and 6 mixed manure treatments. These treatments are combination or not of manure of cattle, cavies, rabbit and poultry. Each treatment has undergone 3 repetitions. The experiment lasted 12 weeks. pH, numerical productivity of E. eugeniae and biomass of E. eugenia have been determined. The results showed that all treatments containing rabbit manure have a final pH close to 7 (neutral pH) with the exception of MG +MR treatment. Those based on poultry or guinea-pig manure and the control range between 5 and 6.5 and are therefore more acidic. The average density and the earthworm biomass of the MC + MR treatment respectively 2889 ± 333 ind./ m2 and 397.22 ± 234.44 g / m2 are different from other treatments. the manure mixture is a privileged environment for Eudrilus eugeniae. It provides a significant biomass of earthworms that can be used in fish farming or in the diet of monogastric animal feed.&#x0D; &#x0D;

Earthworm populations and diversity under annual and perennial wheat in a North to South gradient in Western Europe

The challenge to sustain food security while halting the loss of biodiversity and soil quality might be achieved by a transformation in agriculture from high-input management of annual crops to a more nature-based solution introducing perennial cropping systems. This study analysed earthworm communities (numbers, biomass, ecological categories) and diversity over two years, from annual wheat and perennial intermediate wheatgrass (IWG, Thinopyrum intermedium, Kernza®) within the EU-Biodiversa project NAPERDIV from Southern to Northern Europe. Study sites in France, Belgium and Sweden represented diverse soil, climatic and plant growth conditions. In total, 16 species were identified with IWG in France having the highest (13) and annual wheat in Belgium and Sweden the lowest (7) species numbers. Improved biodiversity under perennial wheat was indicated by alpha-diversity indices (Simpson index, Shannon-Weaver index, Evenness). Earthworm abundance and biomass were generally significantly higher in IWG across the three sites (GLMM model). The overall mean earthworm number under IWG was 424.7 No. m−2 compared to 164.7 No. m−2 for annual wheat. Mean earthworm biomass under IWG was 83.7 g m−2 relative to 45.9 g m−2 under annual wheat, respectively. Remarkably, mean number of juvenile earthworms was several times higher on IWG sites relative to the annual comparatives. Moreover, endogeic and epigeic earthworms were supported on the IWG plots. Beta diversity (Sorensen coefficient) emphasised highest similarity between Belgium and Sweden and lowest between France and Sweden, indicating a possible South to North distribution within Western Europe. The Canonical Correspondence Analysis showed discrete clusters for study sites and species distribution (including the subtypes of Allolobophora chlorotica) in relation to soil parameters (pH, soil texture, TOC, TN, WHC, C–N ratio). The CCA additionally discriminated between annual and perennial plots in France. In summary, earthworm communities were more diverse under IWG and seemed to follow a South to North gradient.

Forest Post Fire Impact on Earthworm Biomass And Abundance in Zawita (duhok Province) Forests Kurdistan Region

Forest Post Fire Impact on Earthworm Biomass And Abundance in Zawita (duhok Province) Forests Kurdistan Region

Earthworms from soils developed after 80 years under tree monocultures at Holt Down, Hampshire, UK

Experimental research from the 1980s showed that tree species influenced soil development where stands of beech (Fagus sylvatica) and small-leaved lime (Tilia cordata) respectivey started to develop a podzolic soil and a brown forest soil after 50 years from near identical origins. Evidence of earthworms was reported but no detail provided. Current work re-examined these soils and a further adjacent spruce (Picea abies) plantation and specifically sampled for earthworms. Standard soil and litter measurements were made, and earthworms were collected by a combined digging and hand-sorting, plus vermifuge technique. The soil surface below lime was covered with Mercurialis perennis, but deep leaf litter was present below beech, with needle cover below spruce. Significantly more earthworms were present below lime, at a density of 29 m−2, when compared with beech (<2 m−2) with spruce intermediate (11 m−2), with a significantly greater earthworm biomass below lime. Of 8 earthworm species collected, more than 70% were from below lime, including Aporrectodea longa, Lumbricus terrestris, A. caliginosa, Octolasion cyaneum and L. rubellus. Those below spruce were mainly Dendrobaena octaedra and only A. longa was found below beech. These observations, after 80 years of differential soil development below tree stands, clearly show continued interactive influences on soils of monoculture tree species with associated ecosystem engineering earthworms.

Landfill leachate has multiple negative impacts on soil health indicators in Hyrcanian forest, northern Iran

The storage of municipal solid wastes in unengineered landfills poses a severe threat to soil functions and health. Wastes seriously threaten human health and the terrestrial ecosystem, especially due to heavy metals. There is a general knowledge gap about the long-term impacts of storage wastes on the soil health indicators which are effective on soil functions. This investigation focuses on the examination of landfill leachate on soil health indicators from different years in the Hyrcanian forest region in northern Iran. For this purpose, soil sampling was done in the summer of 2012 and 2022 (from three depths of 0–10, 10–20, and 20–30 cm and on a surface of 30 cm × 30 cm). Soil samples were randomly collected from a polluted forest used as waste storage and a nearby unpolluted protected forest. In addition to the general soil physical, chemical and biological parameters, the amounts of cadmium (Cd) and lead (Pb) in the soil were also measured. Simultaneously with soil sampling, earthworms (from a depth of 0–30 cm) were collected and identified. Also, the concentration of Cd and Pb in the earthworm's biomass were measured in the laboratory. We found that unpolluted sites had maximum values of N, K, P, and Ca than the polluted sites. In addition, a decrease of soil aggregates stability, nutrient contents, microbial and enzyme activities, and also fauna and microflora abundance were found in the polluted sites in the period 2012–2022. Soil Cd and Pb contents were more in the polluted site in 2022 compared to the unpolluted site. Lumbricus rubellus and Lumbricus terrestris earthworms had significantly higher population in the polluted sites and higher accumulation of Cd and Pb in biomass. According to our results, soil health decreased in the order unpolluted site 2022 > unpolluted site 2012 > polluted site 2012 > polluted site 2022, which corresponds with the reduction of soil health during the release of landfill leachate. This investigation contributes to understand landfill pollution derived from leachate and its effects on soil physical, chemical and biological parameters to help managing landfill leachate. Therefore, the main issue is choosing a landfill system that minimizes the risk of pollution, installing a leachate collection system and constructing a landfill with engineering principles that can reduce the effects of urban waste pollution on soil health. We emphasize that landfilling is dangerous for the environment, so the government should implement sanitary landfilling to prevent further contamination of surface and underground waters, as well as soil in the precious Hyrcanian forest.

Bioaccumulation of pesticide residue in earthworms collected from the agricultural soils of Kuttanad-a unique agroecosystem in India.

Earthworms encompass significant soil faunal biomass and have tremendous potential to provide vital ecosystem services. Earthworms are considered bioindicators of chemical contaminants and can provide early warnings of ecosystem deterioration. Studies pertaining to the accumulation of pesticide residues in earthworm in biomass in agrarian ecosystems are scarce. The Kuttanad agroecosystem (KAE), situated on the southwest coast of India, is one of the few regions globally supporting farming on land below the mean sea level. This investigation was conducted to assess the bioaccumulation of pesticide residues in earthworms from the KAE. The earthworms species Glyphidrilus annandalei collected from agricultural soils of the study area were analyzed for the presence of pesticides residues such as α-BHC, γ-BHC, atrazine, heptachlor, α-chlordane, γ-chlordane, 4,4-DDE, 4,4-DDD, 4,4-DDT, β-endosulfan, and endrin ketone in their biomass. Analysis of the earthworm samples using a gas chromatograph revealed the presence of ten pesticide residues with notable concentrations (α-BHC, 0.36ng/g; γ-BHC, 0.41ng/g; heptachlor, 0.10ng/g; atrazine, 0.89ng/g; α-chlordane, 0.07ng/g; γ-chlordane, 0.10ng/g; 4,4-DDE, 0.05ng/g; 4,4-DDD, 0.11ng/g; 4,4-DDT, 0.31ng/g; β-endosulfan, 0.19ng/g; and endrin ketone, 0.13ng/g). Six groups of pesticide residues are ΣBHC, ΣDDT, atrazine, Σchlordane, endrin ketone, and β-endosulfan were observed during bioaccumulation factor analysis, and the results show the following trend: atrazine > ΣBHC > ΣDDT > Σchlordane > Σendosulfan > Σendrin. As earthworms are a crucial component of this region's food chains, bioaccumulation of pesticide residues in earthworms can pause adverse consequences. Increasing trends in pesticide application in the KAE and bioaccumulation of pesticide residues in earthworm biomass can affect the entire food web.

Combined effects of annual crop agricultural practices on earthworm communities

Earthworm communities are subjected to a great variety of agricultural practices in cropping systems. Most studies that focus on the impacts of agricultural practices on earthworm communities have been carried out on a small combination of practices (e.g., tillage, pesticides, fertilization…) while their simultaneous effects in the field remain little known. In this context, the aim of the present study was to jointly evaluate the effects of (i) tillage (ploughing vs reduced tillage), (ii) fertilization (mineral and organic) and (iii) pesticide applications (herbicides and a combination of insecticides, fungicides and molluscicides) on earthworm communities. Abundance, biomass and richness of earthworm communities were monitored for four consecutive years (2017 to 2020) on a network of 26 fields where annual crops are cultivated, in Brittany (France). The results of this medium-term multifactorial study highlighted that tillage was the most influential agricultural practice on earthworms, followed respectively by fertilization and pesticides application. Our study demonstrated that ploughing was more detrimental to earthworm biomass and richness than to earthworm abundance. Compared to reduced tillage, plough decreased earthworm richness by 1.2-fold, total earthworm biomass by 1.6-fold, Aporrectodea anecic biomass and abundance by respectively 2.7-fold and 2.8-fold. Increased mineral fertilization increased epigeic abundance and biomass as well as Lumbricus anecic biomass. In contrast, organic fertilization did not affect any earthworm community parameters. Increase use of insecticides, fungicides and molluscicides decreased the biomass of Aporrectodea anecic earthworms. Finally, endogeic earthworms have not been impacted by any agricultural practices. To move towards sustainable agriculture, it is necessary to adapt crop management in order to preserve the ecosystem services provided by soil biodiversity, in particular earthworms.

Monitoring the effects of pesticide pellets to address farmers' concerns on soil fauna, specifically earthworms

AbstractSlugs are a major pest in arable agriculture that are typically controlled by using pesticide‐impregnated pellets (molluscicides). We received multiple requests from farmers in 2018 for research into the impact of slug pellets on earthworms because they had been told that ferric‐based pellets were ‘worm‐friendly’. We measured soil fauna feeding activities within Lumbricus terrestris middens on a replicated field plot experiment comparing the recommended product rates of a metaldehyde (4%) based or ferric phosphate EDDS (3%) based slug pellets. There was a significant decrease in feeding activity in the presence of either type of slug pellet, particularly in the top 25 mm of the soil indicating movement away from the pesticide. This could be explained by the significantly lower abundance (numbers and biomass) of earthworms in the topsoil. Four months after ferric phosphate‐based slug pellet application, there was no significant difference between the control and treated plots in earthworm abundance, indicating the effects were temporary. In the laboratory, individual Lumbricus terrestris earthworms consumed up to 4 slug pellets over 14 days and no significant differences in biomass were measured. A burrowing fitness assay indicated that earthworms exposed to ferric phosphate‐based slug pellets burrowed to a greater depth. This suggests an avoidance behaviour response, which could also explain the field results. A consultation with farmers (n = 68) rated this information service as useful and indicated widespread interest in minimizing the effects of pesticides on non‐target soil fauna.