Earthworm Growth Rate Research Articles

Effect of different combinations of feed material of cattle dung with kitchen waste on growth rate of earthworm Eutyphoeus waltoni Michaelsen

In this study the effect of different combinations of animal dung (buffalo, cow, and goat) with kitchen wastes (vegetable wastes and banana peels) on the growth rate of Eutyphoeus waltoni during vermicomposting has been investigated. To identify the most potential feed material combination for enhancement of earthworm growth, the experiment was conducted using different combination of animal dung with kitchen waste as well as dung alone. Significant growth rate of Eutyphoeus waltoni was observed in all the binary combinations of animal dung with vegetable waste and banana peels whereas; the maximum growth rate was observed in the combination of buffalo dung and vegetable waste present in (1:1) ratio. It may be due to the balanced nutrient profile provided by the mixture, which enhances the decomposition process and creates an ideal environment for earthworm growth. The feed material combination of buffalo dung and vegetable waste in (1:1) ratio is suitable for better growth and development of earthworm Eutyphoeus waltoni which not only enhances the growth rate of earthworm but also contribute to efficient waste management by converting organic waste into nutrient-rich vermicompost.

Micro/nanoplastics pollution poses a potential threat to soil health.

Micro/nanoplastic (MNP) pollution in soil ecosystems has become a growing environmental concern globally. However, the comprehensive impacts of MNPs on soil health have not yet been explored. We conducted a hierarchical meta-analysis of over 5000 observations from 228 articles to assess the broad impacts of MNPs on soil health parameters (represented by 20 indicators relevant to crop growth, animal health, greenhouse gas emissions, microbial diversity, and pollutant transfer) and whether the impacts depended on MNP properties. We found that MNP exposure significantly inhibited crop biomass and germination, and reduced earthworm growth and survival rate. Under MNP exposure, the emissions of soil greenhouse gases (CO2, N2O, and CH4) were significantly increased. MNP exposure caused a decrease in soil bacteria diversity. Importantly, the magnitude of impact of the soil-based parameters was dependent on MNP dose and size; however, there is no significant difference in MNP type (biodegradable and conventional MNPs). Moreover, MNPs significantly reduced As uptake by plants, but promoted plant Cd accumulation. Using an analytical hierarchy process, we quantified the negative impacts of MNP exposure on soil health as a mean value of -10.2% (-17.5% to -2.57%). Overall, this analysis provides new insights for assessing potential risks of MNP pollution to soil ecosystem functions.

Effects of elevated temperature and decreased soil moisture content on triclosan ecotoxicity to earthworm E. fetida.

Emerging pollutants and climate change are two main challenges affecting soil organisms today. Changes in temperature and soil moisture with climate change are key factors determining activity and fitness of soil dwelling organisms. The occurrence and toxicity of antimicrobial agent triclosan (TCS) in terrestrial environment is of high concern, while no data are available on TCS toxicity changes to terrestrial organisms under global climate change. The study's aim was to assess the impact of elevated temperature, decreased soil moisture content, and their complex interaction on triclosan-induced changes in Eisenia fetida life cycle parameters (growth, reproduction, and survival). Eight-week TCS-contaminated soil (10-750 mg TCS kg-1) experiments with E. fetida were performed at four different treatments: C (21 °C + 60% water holding capacity (WHC)); D (21 °C and 30% WHC); T (25 °C + 60% WHC); and T + D (25 °C + 30% WHC). TCS had negative impact on the earthworm mortality, growth, and reproduction. Changing climate conditions have altered TCS toxicity to E. fetida. Drought and drought in combination with elevated temperature enhanced the adverse effects of TCS on earthworm survival, growth rate, and reproduction, while single elevated temperature slightly reduced TCS lethal toxicity as well as toxicity to growth rate and reproduction.

Soil degradation kinetics of oxybenzone (Benzophenone-3) and toxicopathological assessment in the earthworm, Eisenia fetida

A preponderance of recent evidence indicates that oxybenzone and other personal-care product chemicals threaten the biota inhabiting various ecological niches. What is understudied is the ecotoxicological impact of oxybenzone, a UV filter in sunscreens and anti-aging products, to terrestrial/soil organisms that are keystone species in these habitats. In the present study, acute exposure (14-day) to oxybenzone resulted in earthworm mortality (LC50 of 364 mg/kg) and growth rate inhibition. Environmentally relevant concentration of oxybenzone (3.64, 7.28 and 36.4 mg/kg) at exposures of 7-day, 14-day, 28-day induced oxidative stress and neurotoxicity followed by perturbations in reproduction processes and changes in vital organs. Decreased levels of superoxide dismutase (SOD) and catalase (CAT) activity were statistically lower than controls (p < 0.05) on day 14 for all three concentrations, while glutathione-s-transferase (GST) activity was significantly elevated from controls on days 7 and 14. On day 28, SOD and CAT activities were either not significantly different from the control or were higher, demonstrating a temporal multiphasic response of anti-oxidant enzymes. GST activity on day 28 was significantly reduced compared to controls. Acetylcholinesterase levels across the three-time points exhibited a complicated behaviour, with every exposure concentration being significantly different from the control. Chronic exposure negatively influences earthworm health status with elevated biomarker values analysed using IBRv2 index. This, in turn, impacted higher levels of hierarchical organization, significantly impairing reproduction and organismal homeostasis at the histological level and manifesting as decreasing cocoon formation and successful hatching events. Thus, the overall findings demonstrate that oxybenzone is toxic to Eisenia fetida at low-level, long-term exposure. Based on the concentration verification analysis and application of the EPA PestDF tool, oxybenzone undergoes single first-order kinetics degradation in OECD soil with DT50 and DT90 as 8.7–28.9 days, respectively.

Individual and histopathological responses of the earthworm (Eisenia fetida) to graphene oxide exposure

The increasing production and applications of graphene oxide (GO) inevitably lead to its entry into the environment. However, its potential toxicity to soil invertebrates is not yet completely known. Herein, the harmful effects of GO on the growth, survival, reproduction, and ultrastructure of earthworms were thoroughly evaluated through acute and chronic toxicity experiments. In the acute toxicity experiments, earthworms were exposed to different concentrations of GO using two test methods: filter paper contact test and natural soil contact test. The lethal concentrations (LC50) for GO at 24-h and 48-h exposure were 2.52 and 2.36 mg mL-1, respectively, in the filter paper contact test and the LC50 on day 14 was 68.8 g kg-1 in the natural soil test. Histopathological observation demonstrated that serious skin and intestinal damage occurred with increasing GO concentrations. In the chronic toxicity test, earthworm growth rate and reproduction were investigated after exposure to 0, 5, 10, 20 and 30 g kg-1 GO in natural soil for 28 and 56 d. Earthworm growth was significantly inhibited after 7, 14, 21 and 28 d of GO exposure. The effect was more significant with increasing GO concentrations and exposure days. Moreover, GO exposure significantly decreased the reproductive capacity of earthworms. When earthworms were exposed to 20 g kg-1 GO for 56 d, the number and hatching rate of cocoons and the number of juveniles decreased by approximately half compared with the control. These findings indicate the potential health risk of GO to E. fetida under high concentrations and long exposure times in soil. Thus, the potential risks associated with the application of GO should receive considerable attention. This study can provide valuable information for assessing the toxicity of carbon nanomaterials in terrestrial ecosystems.

Effects of TiO2 and ZnO nanoparticles on vermicomposting of dewatered sludge: studies based on the humification and microbial profiles of vermicompost.

Nanoparticles (NPs) are prevalent in dewatered sludge, and their presence increases the environmental risks associated with the subsequent sludge treatment process. However, until now, their potential effects on sludge vermicomposting have not been clarified. This study investigated the effects of NPs on sludge humification and microbial profiles during vermicomposting by comparing fresh dewatered sludge substrates with substrates mixed with 0 mg/kg NPs (control), 100 mg/kg TiO2, 500 mg/kg TiO2, 100 mg/kg ZnO, and 500 mg/kg ZnO. The results showed that addition of TiO2 and ZnO NPs to sludge did not significantly affect the growth rate of earthworms and the superoxide dismutase activity in their guts during vermicomposting. Moreover, higher concentrations of the selected NPs promoted the humification index of sludge by 20.7-49.6%, through the formation of polysaccharides, aromatic substances, and organic acids in final vermicomposts. Compared with the control without NP addition, bacterial community diversity was enhanced in treatments with TiO2 and ZnO NPs, and dominant genera differed according to the type and concentration of NPs. This study suggests that the presence of TiO2 and ZnO NP residuals modify the microbial community of sludge, thus promoting sludge humification during vermicomposting.

Management of invasive weed Parthenium hysterophorus through vermicomposting using a polyculture of Eisenia fetida and Eudrilus eugeniae.

Parthenium hysterophorus is considered one of the most noxious terrestrial weeds which needs to be efficiently managed to sustain the environment and vermicomposting are a promising eco-friendly management technique. In the current study, vermicomposting of P. hysterophorus was carried out using a polyculture of two epigeic earthworm species, i.e., Eisenia fetida and Eudrilus eugeniae employed in five different vermireactors referred as Rp1, Rp2, Rp3, Rp4, and Rp5 with five mixing ratios 3:7, 4:6, 5:5, 6:4, and 7:3 respectively of P. hysterophorus to cow dung as a blending material. The nutrients in the final vermicompost were determined by analyzing different physico-chemical parameters and the efficiency evaluated by the growth rate of earthworms. After vermicomposting, TKN, TP, and K contents increased with the highest percentage change of 74.74%, 91%, and 47.2% respectively, compared to initial values. Reduction in C/N ratio was observed in all the vermireactors with the lowest C/N ratio of 9.76. EC increased for all the vermireactors during the process and reached in the range of 3.7-3.85 ds/m at the end of the process. The highest percentage gain in biomass of earthworms was 46.25% in Rp2. Vermicomposting of P. hysterophorus is possible for the management of this invasive weed through polyculture of the earthworms E. fetida and E. eugeniae to obtain a value-added organic fertilizer, i.e., vermicompost by a sustainable process.

Vermicomposting of livestock manure as affected by carbon-rich additives (straw, biochar and nanocarbon): A comprehensive evaluation of earthworm performance, microbial activities, metabolic functions and vermicompost quality

Vermicomposting is an eco-friendly method for treating organic wastes. This study investigated the effects of the addition of straw (S), biochar (B), nanocarbon (N), S + B and S + N to cow dung (CD) on earthworm (Eisenia fetida) performance, microbial properties and vermicompost quality. In general, the earthworm growth rate and cocoon production were enhanced by straw addition, but were inhibited by biochar or nanocarbon addition. However, biochar and nanocarbon increased microbial communities associated with organic matter decomposition, and improved metabolic functions, enzyme activities and vermicompost properties. Moreover, addition of straw in combination with nanocarbon resulted in the highest vermicompost quality index (VQI), and significantly increased the biomass of three different test crops (radish, lettuce and pakchoi). These results indicated that biochar and nanocarbon mainly improved microbial activities, while straw primarily enhanced earthworm performance during vermicomposting. In addition, straw combined with nanocarbon can be used to enhance the agronomic performance of vermicompost.

Toxicological Effects of Petroleum Refinery Sludge on the Terrestial Environment Using Bacteria and Earthworm as Bio Indicators

Aim: The aim of the study is to assess the sublethal (chronic) Ecotoxicological effects ofpetroleum refinery sludge pollution on the biota of the terrestrial environment using the effects on bacteria nitrogen transformation activity and growth rate of the soil fauna, Earthworm (Aporrectodea longa) as bioindicators.&#x0D; Place and Duration of Study: Department of Environmental Management and Toxicology, Federal University of Petroleum Resources, Effurun, between 2017 and 2018.&#x0D; Methodology: The OECD TG 216 (2000) test method was used to determine the chronic effects (% inhibition and EC50) of the petroleum sludge on the nitrogen transformation activity of Nitrobacter sp. in the soil, while the methods of Sandoval et al. [13] and OECD, 207 was used for the chronic effects of the sludge on the growth rate of the earthworms. Bioconcentration factor (BCF) of the sludge in the earthworms was also determined. Both tests were conducted for 28 days. Results from the test with multiple concentrations were analyzed using a regression model (ANOVA). EC5O was also determined using the Probit analytical software. Analyses weredone using ASTM methods.&#x0D; Results: Analysis of the Nigerian petroleum refinery sludge used for this research indicated that the sludge wasacidic with a pH value of 5.91and had a high TPH content of 340,000 mg/kg made mainly of between 10-40 carbon unit compounds. There was a progressive increase in the percentage (%) inhibition of the nitrogen transformation activitiesof the bacteria, from 18.0% (3125 mg/kg) to 79.30% (5000mg/kg) with increase in concentration and time. The effective concentration that decreased 50% (EC50) of the nitrogen transformation activity was 13761.059 mg/kg. The growth rate of the test earthworms decreased from 9.19x103 g/day (375 mg/kg) to 3.55x103 g/day (3000 mg/kg) for the test period. The BCF decreased from 5.168 (375 mg/kg) to 1.22 (3000 mg/kg) in the earthworms, while the EC50for the earthworms was 825.02mg/kg as the concentration of the sludge increased with time.&#x0D; Conclusion: The sludge inhibited the nitrogen transformation activity of Nitrobacter sp. because it exceeded the 25% inhibition limit for chemicals with the potential to cause chronic effects on soil microbial activities as specified in OECD TG 216. Similarly, the sludge reduced the growth rate of the earthworm progressively as the sludge concentration increased in relation to the control. Bioaccumulation factor also increased with increasing sludge concentration and time.

Vermicomposting: a transformation alternative for rumen content generated in slaughterhouses

Rumen content is a waste produced in slaughterhouses. This type of solid waste can cause bad odor and atmospheric pollution if discharged directly into the environment. Additionally, it may spread disease due to the nesting vectors, and the resulting leachate can lead to groundwater contamination. The objective of this study was to determine the suitability of rumen content, waste generated in the slaughterhouse of Villapinzón (Cundinamarca), as raw material for biological transformation into vermicompost at the Fertisoluciones facilities. The characteristics of the rumen content were analyzed, and during the transformation process, three volumetric capacities (T1: 5.94 m3, T2: 23.01 m3, and T3: 16.74 m3) of compost bed were evaluated for 105 days. Through a principal component analysis, the data was reduced in two dimensions that explained 65.8% of the total variance; the first component related to the number of juvenile individuals, high pH, low moisture and temperature; and the second component related to numbers of adults individuals and high temperatures. The earthworm growth rate was determined by the food quality, as well as by bed size. Microbiological and physicochemical analyses were performed on the resulting vermicompost, demonstrating that the transformation process of rumen material into organic fertilizer, performed in Fertisoluciones facilities, fulfills the parameters required by the NTC5167 standard. This study showing the possibility of using a slaughterhouse’s solid waste and convert it into a valuable product to an industrial scale.

Quality of Vermicompost and Microbial Community Diversity Affected by the Contrasting Temperature during Vermicomposting of Dewatered Sludge.

This study aimed to investigate the effects of temperature on the quality of vermicompost and microbial profiles of dewatered sludge during vermicomposting. To do this, fresh sludge was separately vermicomposted with the earthworm Eisenia fetida under different temperature regimes, specifically, 15 °C, 20 °C, and 25 °C. The results showed that the growth rate of earthworms increased with temperature. Moreover, the lowest organic matter content along with the highest electrical conductivity, ammonia, and nitrate content in sludge were recorded for 25 °C indicating that increasing temperature significantly accelerated decomposition, mineralization, and nitrification. In addition, higher temperature significantly enhanced microbial activity in the first 30 days of vermicomposting, also exhibiting the fastest stabilization at 25 °C. High throughput sequencing results further revealed that the alpha diversity of the bacterial community was enhanced with increasing temperature resulting in distinct bacterial genera in each vermicompost. This study suggests that quality of vermicompost and dominant bacterial community are strongly influenced by the contrasting temperature during vermicomposting of sludge, with the optimal performance at 25 °C.

Effect of different organic substrates on reproductive biology, growth rate and offtake of the African night crawler earthworm (Eudrilus eugeniae)

Rapid growth and high fecundity of E. eugeniae makes it a commercial vermicomposting agent. The worm is also a rich protein source (50-70%CP) in livestock diets. The major question, however, is how do we promote earthworm production as a strategy for ecological livestock intensification and integration with crops through earthworm domestication as a source of protein and vermicompost. Reproduction characteristics, growth and offtake of E. eugeniae were studied using four organic substrates including abattoir waste (AW), cattle manure (CM), soya bean crop residue (SBCR) and a mixture of cattle manure and soya bean crop residue (CM+SBCR) aged for 15 days. Irrespective of the substrate, length and biomass of earthworms increased at a decreasing rate between the 1st and 8th weeks. Clitellum appearance was initiated at 31.5±2.4, 32.8±3.2, 33.7±3.3 and 35.5±2.4 days for AW, CM, CM+SBCR and SBCR, respectively, while cocoon initiation was at 69.0±1.4 (AW), 54.9±2.3 (CM), 51.7±1.7 (CM+SBCR) and 60.0±2.4 (SBCR) days. Organic substrate used affected reproductive biology, growth and offtake of E. eugeniae. Higher survivability, total earthworm biomass accumulation and offtake when cultured on CM and a binary combination of CM + SBCR is an indication that a strategy for sustainable crops-livestock integration can be sparked off by earthworm domestication. Earthworm domestication can be promoted using CM or a combination of (CM+SBCR) as substrate.

Eisenia fetida and biochar synergistically alleviate the heavy metals content during valorization of biosolids via enhancing vermicompost quality

Impact of different biochars supplemented (10% w/w) to promote vermicomposting of sewage sludge (SS) and kitchen waste (KW) mixture (SS + KW, 70:30) was studied on the growth, reproduction and survival of earthworms, and ultimately the quality of vermicompost. Four types of biochar used as secondary material for preincubation (16 days) and vermicomposting (30 days) were: pine tree biochar (PTB), poplar plant biochar (PPB), wetland plant biochar (WPB) and yard waste biochar (YWB). Preincubation and vermicomposting of biomass mixture were undertaken in 60 L and 2 L capacity round-shaped bioreactors, respectively. Samples of biomass undergoing degradation were drawn after every 2 days during preincubation and with 5 days interval during vermicomposting to analyze them for plant nutrients and heavy metals contents. Amendment of vermicompost substrate (SS + KW) with biochars; PTB, PPB, WPB and YWB increased the reproduction rate of earthworms (Eisenia fetida) by 44.6, 53.9, 29.3 and 38.8%, respectively as compared to control (no biochar, NB). There has been significant reduction in total content of Cd (0.2–5.1%), Cr (7.3–10.8%), Cu (3.1–7.4%), Mn (3.2–8.4%), Pb (9.0–45.9%) and Zn (1.1–5.7%) by the application of different biochars as compared to NB after vermicomposting. The SEM/EDS images also reflected reduced concentration of these heavy metals in the final vermicompost as compared to initial mixtures. Progressively, biochar amendments increased the concentration of all macronutrients, viz., TN (15.8–31.0%), TP (8.6–9.9%), TK (2.8–17.3%), Ca (4.1–9.9%) and Mg (0.8–12.2%); while, reduced the pH (1.9–2.3%), content of Na (6.6–22.3%), TOC (6.6–15.4%), OM (5.0–8.2%) and C:N ratio (2.6–18.9%). Earthworm body accumulation factor (BAF) of heavy metals was: Cd > Zn > Pb > Cu > Mn > Cr at the termination stage of experiment. In conclusion, amending the SS + KW mixture with 10% (w/w) PPB for vermicomposting rendered higher count of cocoons, growth rate and reproduction rate of earthworms, which ultimately produce nutrients-rich vermicompost lower in heavy metals.

Investigation of rice straw and kitchen waste degradation through vermicomposting

This study investigated the effect of vermicomposting on the degradation of rice straw and kitchen waste. Different ratios of straw and kitchen waste mixtures were used as feedstocks. After vermicomposting the substrates for 45 days under 20–25 °C moisture 60%, the vermicomposting resulted in a significant increase in phosphorous (31.38–55.89%) and potassium (33.40–63.15%), whereas a decrease was seen in TOC (38.24–43.49%) as well as TN (9.01–32.52%). The growth rate of earthworm (Eisenia foetida) was obtained in all feedstocks, the optimal rice straw/kitchen waste ratio for the earthworm growth was 3/2, excessive kitchen waste as negative impacts on the growth of earthworms. The result indicated that vermicomposting rice straw and kitchen waste with Eisenia foetida promoted nutrition content in a short period of time.

Ecotoxicological effects of traffic-related pollutants in roadside soils of Moscow

The objective of this research is to find correlations between traffic-related contaminants in the roadside soils and their ecotoxicity. The study was conducted in Moscow in the vicinity of a highway of 125 000 vehicles per day. The topsoils (0–3 cm depth) were sampled perpendicular to the road at 1-, 6-, 10-, 18- and 50-m distances from the roadbed. Total petroleum hydrocarbons (TPH), polycyclic aromatic hydrocarbons (PAH), heavy metals (HM) in total and phyto-available forms, and deicing salts (DS) were determined. A battery of soil-contacting organisms was tested: phytotoxicity of rye (H. vulgare L.) and garden cress (L. sativum L.); E. foetida earthworm growth rate and mortality; basal and substrate-induced respiration activity, nitrogen fixation and the denitrification activity of the soil microbial complex. To determine the possible risk to aquatic ecosystems, the algal toxicity test (S. quadricauda) was provided. Correlations between "chemical" data and intensity of "biological" effects were analyzed.Concentrations of most contaminants declined to the background values with distance from the road increase. However, the toxicity of roadside soils was obtained for all examined organisms within the whole 50 m zone. Live organisms exhibited different sensitivities to roadside soils pollution. The intensity of inhibition effects decreased in order: higher plants > earthworms and microorganisms > algae. The risk for aquatic ecosystems was assessed as low. Higher plants toxicity correlated with TPH, PAH, some HM, and DS; earthworm toxicity correlated with TPH, some PAH, HM, and DS; microorganism toxicity correlated with TPH and DS; algae had no observed correlations with contaminants. TPH and DS were general ecotoxicants affecting all organisms. Higher plants may be considered the PAH indicators and earthworms as HM indicators. A set of higher plants and earthworms may be recommended as the reduced test-battery of relevant organisms for cost-effective assessment of the toxicity of roadside soils.

Multi-level ecotoxicological effects of imidacloprid on earthworm (Eisenia fetida)

As a neurotoxic insecticide, imidacloprid (IMI) has been widely used for crop protection. However, continuous application of such pesticide in the environment may damage the non-target organisms in soil. In the present study, we aimed to investigate the effects of IMI on earthworms in terms of survival, avoidance behavior, reproduction, detoxification enzyme activity and gene expression using a systematic experimental approach. The results showed that the 14-day LC50 value of IMI was 2.26 (2.09–2.43) mg a.i. kg−1, and the 2-day AC50 value (concentration inducing an avoidance rate of 50%) of IMI was 1.34 (1.02–1.91) mg a.i. kg−1 to E. fetida. For reproduction, the 56-day EC50 value of IMI was 0.87 (0.66–1.33) mg a.i. kg−1 to E. fetida, and there was a positive correlation between the growth rate of earthworms and the number of juveniles in IMI treatments. Activities of carboxylesterase (CarE) and glutathione-S-transferases (GST) in earthworms were disturbed by IMI exposure. Moreover, effects of IMI on the CarE activity in earthworms were more severe and sensitive compared with the GST activity. The expressions of annetocin (ann) and calreticulin (crt) at the transcriptional level were decreased upon IMI exposure, reaching the lowest levels of 0.09 fold and 0.16 fold on day 7 and day 14, respectively. Transcriptionally controlled tumor protein (tctp), heat shock protein 70 (hsp70) and gst exhibited relatively obvious variations (up-regulation or down-regulation) when the exposure duration was extended. Taken together, these results comprehensively contributed to further understandings of the impacts of IMI on earthworms.

Vermicomposting of different Varieties of Leaves (Difference in the Growth Rate of Earthworms &amp; Quality of Manure)

Vermicomposting of different Varieties of Leaves (Difference in the Growth Rate of Earthworms &amp; Quality of Manure)

The vitality of the earthworm developing in soil treated with different concentrations of leaves and fruits powders of Melia azaderach L

The present study investigated the effect of five concentrations (1,2.5,5,7.5,10%) of leaves and fruits of Melia azaderach L . plant powder on relative growth rate of earthworm after one and two months post treatment , the results revealed that the relative growth rate was decreased and the least one was the concentration at 7.5% for leaves and fruits powder of Melia azaderach L. plant,of 44.4%and71.55%, respectively. In addition , the effect of these concentrations on increasing and decreasing worms weights was studied and showed that all concentrations led to weight decrease of in treated worms especially at the concentration 7.5% during two breeding period , also noticed that during a second period of Treatment with leaves powder at 5,7.5, 10% concentrations during the second breeding period led to worms death and incomplete life cycle.Death. Furthermore, the percentage of death was estimated at the same concentrations of leaves and fruits powder during two breeding periods, in additon to the effect of these concentrations on protein content in worm bodies, the thickness of body wall (epidermis and body wall )was estimated in addition to the thickness of the epithelial layer of digestive tract, and the effect on the internal structures in treated worms.

Acute toxicity of chemical pesticides and plant-derived essential oil on the behavior and development of earthworms, Eudrilus eugeniae (Kinberg) and Eisenia fetida (Savigny).

Comparative toxicity of two chemical pesticides (temephos and monocrotophos) versus a plant-derived betel leaf oil Piper betle (L.) to earthworm Eudrilus eugeniae (Kinberg) and redworm Eisenia fetida Savigny, historically: Eisenia foetida (Savigny 1826), was evaluated. Mortality rate was more prominent in temephos at 100μg concentration to both the earthworms in filter paper test (FPT) as well as 10mg concentration in artificial soil test (AST). In contrast, P. betle does not display much mortality rate to both the earthworms even at 1000mg of treatment concentrations. The lethal concentration (LC50) value was observed at 3.89 and 5.26mg/kg for temephos and monocrotophos against E. eugeniae and 3.81 and 5.25mg/kg to E. fetida, respectively. Whereas, LC50 value of betel leaf oil was only observed at 3149 and 4081mg/kg to E. eugeniae and E. fetida, respectively. Correspondingly, the avoidance or attraction assay also displayed that earthworms were more sensitive to the soil containing chemical pesticides. Whereas, the avoidance percentage was decreased in the P. betle oil. Similarly, sublethal concentration of chemical pesticides (5 and 6.5mg) significantly reduced the earthworm weight and growth rate. However, P. betle oil did not change the developmental rate in the duration of the assay (2, 7 and 14days) even at 4000mg treatment concentration. The enzyme ratio of CAT and SOD was also affected significantly after exposure to the chemical pesticides (6.5mg/kg). Hence, our study implied the risk assessment associated with the chemical pesticides and also recommends plant-derived harmless P. betle oil against beneficial species as an alternative pest control agent.

Milled cereal straw accelerates earthworm (Lumbricus terrestris) growth more than selected organic amendments

Earthworms benefit agriculture by providing several ecosystem services. Therefore, strategies to increase earthworm abundance and activity in agricultural soils should be identified, and encouraged. Lumbricus terrestris earthworms primarily feed on organic inputs to soils but it is not known which organic amendments are the most effective for increasing earthworm populations. We conducted earthworm surveys in the field and carried out experiments in single-earthworm microcosms to determine the optimum food source for increasing earthworm biomass using a selection of crop residues and organic wastes available to agriculture. We found that although farmyard manure increased earthworm populations more than cereal straw in the field, straw increased earthworm biomass more than manures when milled and applied to microcosms. Earthworm growth rates were positively correlated with the calorific value of the amendment and straw had a much higher calorific value than farmyard manure, greenwaste compost, or anaerobic digestate. Reducing the particle size of straw by milling to <3mm made the energy in the straw more accessible to earthworms. The benefits and barriers to applying milled straw to arable soils in the field are discussed.