Enriched pressmud vermicompost production with green manure plants using Eudrilus eugeniae

Bioconversion of cow manure through vermicomposting: effects of tylosin concentration on the weight of worms and manure quality

This study investigated batch-fed vermicomposting of cow manure, with a specific focus on assessing the effects of tylosin on the weight of earthworms and the overall quality of the resulting manure. Five reactors, including three concentrations of tylosin (50, 100, and 150 mg/kg) and two control reactors, were employed. Residual tylosin concentrations were measured using high-performance liquid chromatography (HPLC). Quality parameters such as pH, temperature, volatile solids (VS), organic carbon content (OCC), electrical conductivity (EC), ash content, C/N ratio, total Kjeldahl nitrogen (TKN), and microbial content were evaluated. The toxicity and maturity of vermicompost were assessed by determining the germination index (GI). The study also monitored variations in the earthworm's weight. The results demonstrated a decreasing trend in VS, OCC, C/N, and fecal coliforms, along with increased pH, EC, ash content, and TKN during the vermicomposting process. Furthermore, investigations revealed significant reductions in the reactors with tylosin concentrations of 50, 100, and 150 mg/kg, resulting in the removal of 98%, 90.48%, and 89.38% of the initial tylosin, respectively. This result confirms the faster removal of tylosin in reactors with lower concentrations. Degradation of tylosin also conforms to first-order kinetics. The findings showed a significant influence of tylosin on the weight of Eisenia fetida earthworms and the lowest antibiotic concentration led to the highest weight gain. Finally, the high percentage of germination index (90-100%) showed that the quality and maturity of vermicompost is by national and international standards.

Enhanced vermicomposting of rice straw and pressmud with biogas slurry employing Eisenia fetida: Production, characterization, growth, and toxicological risk assessment

The biogas plant plays a dual role: it directly provides energy and indirectly promotes organic farming through outlet slurry. However, agricultural biomass wastes such as rice straws (RS) and pressmud (PM), which can't be used as fertilizers on their own, were vermicomposted (60 days) with biogas slurry (BS), using earthworm, into four blends: T1(BS, 100%), T2(3:2, BS: RS), T3(3:2, BS: PM), and T4(3:1:1, BS: RS: PM). The characterization, elemental analysis, and toxicological risk assessment of derived vermimanure were carried out using various analytical tools, such as an organic elemental analyzer such as CHNS, FT-IR, FESEM-EDXA, XPS, and ICP-OES. The pH, electrical conductivity, and C/N values were within 7.1-7.8, 3.2-6.0 dSm-1, and 12-15, respectively, for all treatments. The proportions of N (38%), P (70%), K (58%), Mg (67%), Ca (42%), and ash (44%), increased significantly (P < 0.05) over the initial feedstocks. The ecological risks of heavy metals (Zn, Cu, Ni, Pb, Cd, and Cr) in all feedstocks were found to be under WHO-permitted levels. The growth performance of earthworms was also considerably higher (P < 0.05) over the control feedstock group. The analytical methods verified that feedstock T4 (3:1:1, BS: RS: PM) was more porous, containing NH4+, PO43-, K+, and other nutrients. Pellets of all vermimanure groups keep 65-75% of the original volume. As well, when these pellets have been employed for agronomy and dispersed in the field, they will cause less dust than traditional or powdered compost or manure. In comparison to the control group, the synergistic approach of RS, PM, and BS in vermimanure significantly (P < 0.05) enhanced seed germination (83%), vigour index (42.5%), and decreased mean germination time by 27%. Furthermore, pot trials with Abelmoschus esculentus seed indicated that seedlings cultivated with 40% vermimanure of T4 (3:1:1, BS: RS: PM) mixed soil showed high growth in shoot, root, and plant yield.

A Critical Review on the Vermicomposting of Organic Wastes as a Strategy in Circular Bioeconomy: Mechanism, Performance, and Future Perspectives

AbstractTo meet the current need for sustainable development, vermicomposting (VC), a natural, eco-friendly, and cost-effective technology, can be a wise selection for the bioconversion of organic wastes into value-added by-products. However, no one has tried to establish the VC technology as an economically sustainable technology by exploring its linkage to circular bioeconomy. Even, no researcher has made any effort to explore the usability of the earthworms (EWs) as a protein supplement while assessing the economic perspectives of VC technology. Very few studies are available on the greenhouse gas (GHG) emission potential of VC technology. Still, the contribution of VC technology towards the non-carbon waste management policy is not yet explored. In the current review, a genuine effort has been made to inspect the contribution of VC technology towards the circular bioeconomy, along with evaluating its capability to bioremediate the organic wastes generated from domestic, industrial, and agricultural premises. The potential of the EWs as a protein source has also been explored to strengthen the contribution of VC technology towards the circular bioeconomy. Moreover, the linkage of the VC technology to the non-carbon waste management policy has been comprehensively demonstrated by highlighting its carbon sequestration and GHG emission potentials during the treatment of organic wastes. It has been observed that the cost of food production was reduced by 60--70% by replacing chemical fertilizers with vermicompost. The implication of the vermicompost significantly lessened the harvesting period of the crops, thereby helping the farmers attain higher profits by cultivating more crops in a single calendar year on the same plot. Furthermore, the vermicompost could hold the soil moisture for a long time, lessening the water demand up to 30-40%, which, in turn, reduced the frequency of irrigation. Also, the replacement of the chemical fertilizers with vermicompost resulted in a 23% increment in the grapes' yield, engendering an extra profit of up to 110000 rupees/ha. In Nepal, vermicompost has been produced at a cost of 15.68 rupees/kg, whereas it has been sold to the local market at a rate of 25 rupees/kg as organic manure, ensuring a net profit of 9.32 rupees/kg of vermicompost. EWs embraced 63% crude protein, 5-21% carbohydrates, 6-11% fat, 1476 kJ/100 g of metabolizable energy, and a wide range of minerals and vitamins. EWs also contained 4.11, 2.04, 4.43, 2.83, 1.47, and 6.26  g/kg (on protein basis) of leucine, isoleucine, tryptophan, arginine, histidine, and phenylalanine, respectively, enhancing the acceptability of the EW meal (EWM) as the protein supplement. The inclusion of 3 and 5% EWM in the diet of broiler pullets resulted in a 12.6 and 22.5% increase in their feed conversion ratio (FCR), respectively after one month. Similarly, when a 100% fish meal was substituted by 50% EWM and 50% fish meal, the FCR and growth rate of Parachanna obscura were increased substantially. The VC of maize crop residues mixed with pig manure, cow dung, and biochar, in the presence of Eisenia fetida EWs, yielded only 0.003-0.081, 0-0.17, and 130.40-189.10 g CO₂-eq.kg^-1 emissions of CO₂, CH₄, and N₂O, respectively. Similarly, the VC of tomato stems and cow dung ensured 2.28 and 5.76 g CO₂-eq.kg^-1 CO₂ emissions of CH₄ and N₂O, respectively. Additionally, the application of vermicompost at a rate of 5 t/ha improved the soil organic carbon proportion and aggravated carbon sequestration. The land application of vermicompost improved micro-aggregation and cut down the tillage, reducing GHG emissions and triggering carbon sequestration. The significant findings of the current review suggest that VC technology potentially contributes to the concept of circular bioeconomy, substantially negotiates potential GHG emissions, and complies with the non-carbon waste management policy, reinforcing its acceptability as an economically sound and environmentally benevolent organic waste bioremediation alternative.

Vermicomposting of Pleurotus eryngii spent mushroom substrates and the possible mechanisms of vermicompost suppressing nematode disease caused by Meloidogyne incognita

The mushroom industry produces a large amount of spent mushroom substrate (SMS), which requires a large geographical footprint and causes pollution. Vermicomposting is a low-cost technology for its value in recycling of organic wastes and production of beneficial organic fertilizers. In this study, the changes of physicochemical properties was characterized during vermicomposting of Pleurotus eryngii SMS with cow dung (CD) as amendment. The efficiency and possible mechanisms of vermicompost suppressing disease induced by Meloidogyne incognita was also investigated. Six combinations with different ratios of SMS and cow dung (CD) was included in the vermicomposting using Eisenia fetida. Effect of vermicompost against disease induced by M. incognita on tobacco was conducted under greenhouse condition. And the possible mechanisms of vermicompost suppressing M. incognita was investigated by evaluated the species diversity of nematode-trapping fungi (NTF) in soil, and the defense response enzymes in tobacco. The combination of 65% SMS +35% CD was more suitable for vermicomposting, in which the highest vermicompost production (57%) and earthworm biomass increment (268%) were achieved. Additionally, the reduction in pH, total organic carbon, carbon: nitrogen ratio, and the pronounced elevation in four overall nutrient status were also observed. Soil amended with vermicompost (100:1 w/w) showed 61% control efficiency against nematode disease caused by M. incognita on tobacco, which significantly higher than that of the normal compost (24%). Comparing to the normal compost, the potential mechanism of vermicompost suppressing M. incognita could be rely on promoting species diversity of NTF in soil and enhancing the activities of the defense response enzymes in tobacco plant. Our findings indicate that vermicomposting is a promising technology for recycling of P. eryngii SMS, and the resulting vermicompost as organic fertilizer can be sued for management of the diseases caused by root-knot nematodes. This study establish a sustainable avenue for P. eryngii SMS disposal and a practical manner for controlling pathogens.

Production and characterization of sustainable vermimanure derived from poultry litter and rice straw using tiger worm Eisenia fetida

Poultry litter (PL) and rice straw (RS), commonly available waste materials, pose severe threat to environment, if not properly managed. As viable waste treatment method, vermi-transformation of PL into enriched vermimanure was done using RS and cow dung (CD) with different feedstocks (FS) combinations like FS0_{(CD without earthworm),} FS1_(CD), FS2_{(1CD: 1RS)}, FS3_{(1CD: 1PL)} and FS4_{(1CD: 1RS: 1PL)} for 110 days. Increased growth performance (P < 0.05) of Eisenia fetida, macronutrient levels, and a consistently lower carbon-to-nitrogen ratio (C/N) emphasize the importance of RS and PL in the vermimanuring process. Several analytical techniques have revealed the presence of functional groups, nitrate (NO₃^-), phosphate (PO₄^3-), and potassium ions (K⁺) as well as the high porosity of the matured vermimanures. Therefore, using earthworms, the feedstock FS4_{(1CD: 1RS: 1PL)} could be successfully biotransformed into sustainable manure lowering the usage of chemical fertilizers and rice straw burning.

Bioconversion of fruit waste and sewage sludge mixtures by black soldier fly (Diptera: Stratiomyidae) larvae

Bioconversion of fruit waste (FW) and sewage sludge (SS) sludge mixtures into valuable products was investigated using black soldier fly (Hermetia illucens) larvae (BSFL) under a lab-scale trial. For that, five different setups of FW and SS mixtures (100FW; 100SS; 70SS+30FW; 50SS+50FW; 70FW+30SS) were prepared and changes in larval biomass, feed loss, and residual waste physicochemical properties were estimated until the emergence of fly in all waste mixtures. BSFL caused a significant decrease in total organic carbon (11.71-34.79%) and carbon-to-nitrogen ratio (C/N ratio) while the increase in total nitrogen (8.35-123.30%), total phosphorus (17.02-143.36%), and total potassium (19.40-48.87%) contents in the feedstock. The germination index and C/N ratio of frass were below the standards decided for manure quality in a few setups suggesting the non-stability of frass for agronomic applications due to the short duration (20 d) of composting. Larval biomass yield, feed conversion ratio and nutrient mineralization were found to be higher in 50SS+50FW and 70FW+30SS feedstock combinations suggesting their suitability as ideal feedstock for optimal BSFL cultivation. The impact of toxic substances in sewage on BSFL survival, growth and waste stabilization processes, and frass metal enrichment could be investigated in future studies.

Characterization of vermicompost of coconut husk mixed with cattle dung: physicochemical properties, SEM, and FT-IR analysis

The present work evaluated the potential of vermicomposting in management of different ratios of coconut husk waste (CH) and cattle dung (CD) viz (waste: CD) 0:100 (CH₀), 25:75 (CH₂₅), 50:50 (CH₅₀), 75:25 (CH₇₅), and 100:0 (CH₁₀₀) using Eisenia fetida for 120 days. The physicochemical properties were analyzed in vermicompost samples taken on the 0 and 120th day. Co-composting with cattle manure improved their acceptability for E. fetida as well as their physicochemical properties. In a 50:50 (CH₅₀) ratio, the lowest mortality and maximum growth in terms of number and biomass of earthworms were observed. The results revealed that during pre-vermicompost to post-vermicompost, nutrients such as nitrogen, phosphorus, and sodium increased, whereas in all vermicomposting end products organic carbon and the C:N ratio decreased significantly. Except zinc, all heavy metals decreased significantly (p < 0.05) over initial in all the feed mixtures. Seed germination tests indicated that the mature and non-phytotoxic vermicompost has been formed at the end of the experiment. The Fourier transmission infrared spectroscopy (FT-IR) and scanning electron microscopic (SEM) images of vermicompost demonstrated the excellent maturity of the compost.

Valorization of phyto-biomass with tertiary combination of animal dung for enriched vermicompost production

A study was conducted for 90 days in two cycles on 45^thday (Cycle I), and 90th day (Cycle II) in 144 vermibins with precomposted cow dung (T1), elephant dung (T2), cow dung + elephant dung (T3) in combination with leaf substrates of Ficus religiosa, Azadirachta indica, Terminalia catappa, Carica papaya, Vitex negundo, Acalypha indica and Borassus flabellifer to generate nutrient-enriched vermicompost. Different vermibin feedstock materials were retained as experimental setup in other substrates with earthworm (vermicompost) and without earthworm (compost). This method was employed in the current study to decompose environmental leaf debris into the earthworm's mass production and transform it into high-value manure for long-term soil fertility control. The majority of the substrates exhibit pH and electrical conductivity in vermicomposts showed an increment while the total organic carbon and carbon to nitrogen ratio were significantly lowered. A prominent percentage increment of total NPK contents (P < 0.05) in vermicompost over initial values (N: 7.09-164.03; P: 4.39-101.09; K: 0.45-84.10). Among the vermibed substrates, Ficus religiosa leaf litter mixed with T3 showed stabilized cocoons and juveniles in Cycle I (45 days), while sub-adults and adults growth was favored in Cycle II (90 days). The higher reproductive potential of earthworms could be due to the composition and palatability of the substrate combination. This study provides a platform for utilizing leaf wastes in combination with animal wastes amended to reproduce earthworms, nutrient enrichment which could benefit soil fertility improvement.

Nutrient recovery and changes in enzyme activity during vermicomposting of hydrolysed chicken feather residue

Chicken feathers are hazardous to the environment because of their poor digestibility and potential as a source of environmental contaminants. However, this waste contains valuable plant nutrients that can be recovered and used to improve soil fertility and agricultural productivity. The objectives of this study were to evaluate how effective vermicomposting is at recovering nutrients and changes in enzymatic activity during vermicomposting of hydrolysed chicken feather residues (HCFR). The study included four treatments with three replications at different HCFR and pelletized wheat straw (PWS) mixing proportions: (T1) 25% HCFR+75% PWS with earthworms, (T2) 25% HCFR+75% PWS without earthworms, (T3) 50% HCFR+50% PWS with earthworms, and (T4) 50% HCFR+50% PWS (w/w) without earthworms. Eisenia andrei was used in the experiment for 120 days. Earthworm treatments recovered more available plant nutrients than non-earthworm treatments by 14% N - NO 3 - (T1); 50% K (T3); 47% Mg (T3); 75% P (T3); 55% B (T3); 34% Cu (T3); 40% Fe (T1); 46% Mn (T3); 11% Zn (T1). However, N - NH 4 + was significantly reduced by -80% (T1). Acid phosphatase, arylsulphatase, alanine aminopeptidase, and leucine aminopeptidase were more active in the treatments with earthworms and positively correlated with P and C: N ratio. Alanine aminopeptidase (3752 µmol AMCA.g-1.h-1) and leucine aminopeptidase (4252 µmol AMCL.g-1.h-1) had higher activities in T3 on day 60 of vermicomposting. As a result, the earthworm treatment recovers more plant nutrients than the non-earthworm treatments, and it can be recommended as a better vermicomposting approach for nutrient recovery from HCFR.

Juxtaposing the quality of compost and vermicompost produced from organic wastes amended with cow dung

Composting is a propitious technology to change bio-degradable solid waste into organic fertilizers. Considering this, five types of organic waste viz., leaf litter (Tectona grandis), water hyacinth (Eichhornia crassipes), cauliflower waste (Brassica oleracea var. botrytis), coir pith, and mushroom spent waste were composted with and without the use of earthworm (Eisenia fetida). The reaction (pH) and electrical conductivity of compost and vermicompost ranged from 6.98 to 7.45 and 6.97 to 7.36, 0.11 to 0.21 dSm^-1, and 0.11 to 0.25 dSm^-1, respectively. The chemical oxygen demand both the compost and vermicompost ranged from 687 to 1170 mg l^-1 and 633-980 mg l^-1 respectively. Cation exchange capacity (CEC) ranged from, 75 to 121 (c mol (p+) kg^-1, and 80 to 127 (c mol (p+) kg^-1, respectively. The C:N of compost and vermicompost varied from 16:1 to 33:1 and 12:1 to 19:1, respectively. The organic carbon content was decreased (18.3-38.7%), while secondary and micronutrient contents increased over the initial concentration. The NH₄⁺ and NO₃^- content of compost and vermicompost ranged from 270 to 510 mg kg^-1 and 230-430 mg kg^-1, 560 to 105 mg kg^-1, and 690-1100 mg kg^-1, respectively. The nitrification index (NH₄⁺/NO₃^-) ranged from 0.3 to 0.9 in composts and 0.3 to 0.6 in vermicomposts. The dehydrogenase and urease activity varied from 685 to 1696 μg g^-1 hr^-1 and 938-2549 μg TPF g^-1 day^-1 respectively. The bacteria, fungi and actinomycetes population were 2-3, 0.3-0.7 and 3-8 times more in vermicompost over the corresponding compost. This study confirmed that compared to compost, vermicompost showed better nutrients and microbial properties.

Current scenario of solid waste management techniques and challenges in Covid-19 - A review

Annually, world generates 2.01 billion tonnes of solid wastes and it is expected to generate 2.2 billion tonnes of solid waste by 2025. Globally double the amount of waste generation was anticipated by 2050, hence an urgent action is required for this intricate problem in adopting better management techniques and recycling strategies. Unfortunately, poor management of wastes causes vulnerable effects to the society in terms of health. Waste management is the key infrastructure to be developed in society, but so far it is not recognized as much in many developing countries. Significant innovations and improvements are made in the last few decades globally, but still 2 to 3 billion people around the world lack access to waste collection services. The aim of this present study is to give an overview of different types of waste techniques that are effectively followed by different countries and the action plans need to follow. This review focuses on the global current scenario of waste generation, and its management methods with relevant literatures providing the upgrades in the phases of waste management services like collection and transport, various techniques adopted for waste management, policies and legislation, countries investment in waste management process and the impact of solid waste management during Covid-19. Collectively we conclude that Asian countries need to allot more fund for handling solid waste. Also with the available waste management technique, it is not possible to achieve zero waste. Therefore, more new techniques are needed to be adapted.

Combined effects of green manure and zinc oxide nanoparticles on cadmium uptake by wheat (Triticum aestivum L.)

Cadmium (Cd) toxicity in agricultural soils is serious concern these days which needs continuous attention. Little is known about the combined use of berseem and/or maize residues soil applied as a green manure alone or along with foliar dressing of zinc oxide nanoparticles (ZnONPs) on Cd accumulation in wheat (Triticum aestivum L.). A pot experiment under ambient conditions with wheat grown in Cd-contaminated soil was performed after soil applied different green manure amendments and foliar dressing of ZnONPs was done during plant growth and plants were harvested at full maturity. Compared with control, plant growth attributes and biomass of above ground parts substantially increased with applied amendments being maximum with combined use of ZnONPs + B75 (berseem residue, 75 mg/kg) followed by ZnONPs + M75 (maize residue, 75 mg/kg). All the treatments improved the leaf chlorophyll contents and improved the leaf antioxidant enzyme activities thereby reduced the leaf electrolyte leakage. The Cd accumulation in roots and aboveground parts of the wheat was reduced especially in ZnONPs + B75 followed by ZnONPs + M75. The higher rate of soil applied amendments along with NPs minimized the available Cd in soil extracts but soil post-harvest pH was not much affected by the applied amendments. In conclusion, incorporation of berseem and maize residues as a green manure applied in Cd-contaminated soil combined with foliar NPs may decrease Cd phytoavailability and its accumulation in wheat grains. However, substantial field studies are required under various environmental conditions before final recommendations at field levels.

Draft Genome Sequence of the Earthworm Eudrilus eugeniae

Background: Earthworms are annelids. They play a major role in agriculture and soil fertility. Vermicompost is the best organic manure for plant crops. Eudrilus eugeniae is an earthworm well suited for efficient vermicompost production. The worm is also used to study the cell and molecular biology of regeneration, molecular toxicology, developmental biology, etc., because of its abilities like high growth rate, rapid reproduction, tolerability toward wide temperature range, and less cost of maintenance. Objective: The whole genome has been revealed only for Eisenia andrei and Eisenia fetida. Methods: In the present work, we sequenced the genome of E. eugeniae using the Illumina platform and generated 160,684,383 paired-end reads. Results: The reads were assembled into a draft genome of size 488 Mb with 743,870 contigs and successfully annotated 24,599 genes. Further, 208 stem cell-specific genes and 3,432 non-coding genes were identified. Conclusion: The sequence and annotation details were hosted in a web application available at https://sudhakar-sivasubramaniam-labs.shinyapps.io/eudrilus_genome/.

Vermicomposting of textile mill sludge employing Eisenia fetida: Role of cow dung and tea waste amendments

Vermicomposting of textile mill sludge (TMS) with cow dung (CD) and tea waste (TW) as amendments was done in seven different combinations using Eisenia fetida for 90 days. Results revealed that pH decreased from 7.68-8.63 to 7.09-7.59. TOC content and C/N ratio reductions were in range of 15.71-20.08% and 39.33-50.05%, respectively (P < 0.05). The macronutrients in the form of TN, TP, and TK increased 0.38-0.64, 1.07-2.27, and 0.56-1.98 times respectively after end of bioconversion process (P < 0.05), among increases in ash content and EC. The biomass and cocoon production of E. fetida increased significantly (P < 0.05), while high mortality rate of earthworms was observed in treatments containing 50% or more TMS content. The bacterial population beneficial for degradation of organic matter increased significantly over initial substrates (0th day) (P < 0.05). Increased humification index in end-product indicated better maturity of vermicompost as observed in treatments containing higher proportions of amendments. The addition of amendments favored earthworm activity which significantly decreased the heavy metal concentration (Fe, Cu, Pb, Zn) in the end-product. The study concluded that sustainable utilization of TMS could be achieved for cleaner and enriched vermicompost production by addition of amendments CD and TW in proportions of 50% and above.

Eisenia fetida for vermiconversion of waste biomass of medicinal herbs: Status of nutrients and stability parameters

Vermiconversion possibility of waste biomass of two medicinal herbs Zingiber officinale and Curcuma longa has been investigated. The Eisenia fetida, an epigeic earthworm was used in the vermicomposting process. The vermicomposting caused shifting in pH towards neutral range, reduction in electrical conductivity, total organic carbon, C/N and C/P ratios whereas1.8-2.73 folds enhancement in macronutrients (TKN, AP, T Ca and T Mg) and ash contents in the substrate mixture. The heavy metals and trace elements content in the vermicompost were found within 3.25-1380 mg/kg and are under the permissible limits of compost applications. Besides, high germination index value in the vermicompost extract indicates loss of phytotoxicity and safe agricultural application potential of the end product. Finally, enhanced growth in Eisenia fetida confirms the application potential of harvested waste biomass as the raw materials for vermiconversion process.

Detoxification of coir pith through refined vermicomposting engaging Eudrilus eugeniae

Hazardous coir industrial waste, coir pith has been subjected to 50 days vermicomposting with Eudrilus eugeniae by amending nitrogenous legume plant, Gliricidia sepium together with cattle dung in different combinations, after 21 days precomposting using Pleurotus sajor-caju spawn. An increase in electrical conductivity, total NPK and calcium, and a decrease in organic matter, total organic carbon, C/N ratio, C/P ratio and total phenolic content in the final vermicompost were observed. Dehydrogenase, urease and cellulase activity peaked up to 30 days of vermicomposting and then declined. The phytotoxicity studies with Brassica juncea, C/N ratio and enzyme activities confirmed the stability and maturity of vermicompost. The results also demonstrated that the 2:3:1 ratio (coir pith + Gliricidia sepium + cow dung) is a suitable effective combination for nutrient-rich (N: 2.43%; P: 0.92%; K: 2.09%) vermicompost production. The total phenolic contents declined during the vermicomposting with a lower final content of 21.26 mg/g GAE in 2:3:1 combination of substrates from the initial level (105.56 mg/g GAE). Besides, the concentration of total phenol contents inversely related to the germination index of Brassica juncea (r = -0.761), indicating that the phenolic content could also play an important role in phytotoxicity. Growth and fecundity of Eudrilus eugeniae in 2:3:1 combination revealed the acceptability and rapid decomposition of coir pith substrate into vermifertilizer.

Effect of Different Enriched Vermicomposts, Humic Acid Extract and Indole-3-Acetic Acid Amendments on the Growth of Brassica napus

Humic acid (HA) is a specific and stable component of humus materials that behaves similarly to growth stimulants, esp. auxin hormones, contributing to improving growth indices and performance of plants. As a rich source of HA, vermicompost (VC) is also a plant growth stimulating bio-fertilizer that can enhance growth indices and performance in plants. The purpose of the present study is to compare the influence of VC enriched with bacterial and/or fertilizer, commercial humic acid (CHA) extract, and indole-3-acetic acid (IAA) on improving growth characteristics and performance of rapeseed under greenhouse conditions. The results showed the complete superiority of VC over the CHA and IAA (approximately 8% increase in the dry weights of root and aerial organ and nearly three times increase in seed weight). The highest values of these indices were obtained with VC enriched with Nitrogen, Sulfur, and Phosphorus, Azotobacter chroococcum and Pseudomonas fluorescens; the lowest value was obtained with VC enriched with urea. Additionally, the application of 3% VC and the control involved the highest and lowest values in all traits, respectively. The SPAD (chlorophyll index) value and stem diameter were not significantly affected by different application levels of VC. Overall, the applications of IAA and the CHA were not found to be suitable and therefore not recommended.

Combination of biological processes for agro-industrial poultry waste management: Effects on vermicomposting and anaerobic digestion

This study evaluated the combination of bioprocesses to increase the utilization of agro-industrial poultry wastes. Composting piles were submitted to hydration and fraction separation (FS) and then, the solid fraction was vermicomposted and the liquid fraction was anaerobically digested. Composting followed by hydration and FS prior to vermicomposting enhanced earthworm adaptation and survival by reducing salt levels (50%), total organic carbon, and total nitrogen which may be limiting to vermicomposting at high concentrations. These strategies providing the production of up to 300 new cocoons and 360 young earthworms more than the control treatment. In addition to providing a favorable environment for earthworm growth, the combination of bioprocesses resulted in a high-quality organic fertilizer free of phytotoxic compounds and with phytostimulant properties (germination index higher than 100%). Energy recovery was greater in the treatment without the precomposting step (T₀) (461.8 L CH₄ kg^-1. Volatile Solids_added). The results show that combining the bioprocesses is a sustainable alternative for managing poultry wastes not only in terms of the recycling of nutrients but also by providing a clean source of energy.

Activation of biochar through exoenzymes prompted by earthworms for vermibiochar production: A viable resource recovery option for heavy metal contaminated soils and water

The industrial revolution and indiscriminate usage of a wide spectrum of agrochemicals account for the dumping of heavy metals in the environment. In-situ/ex-situ physical, chemical, and bioremediation strategies with pros and cons have been adopted for recovering metal contaminated soils and water. Therefore, there is an urgent requirement for a cost-effective and environment-friendly technique to combat metal pollution. Biochar combined with earthworms and vermifiltration is a suitable emerging technique for the remediation of metal-polluted soils and water. The chemical substances (e.g., sodium hydroxide, zinc chloride, potassium hydroxide, and phosphoric acid) have been used to activate biochar, which also faces several shortcomings. Studies reveal that extracellular enzymes have been used to activate biochar which is produced by earthworms and microbes that can alter the surface of the biochar. The present review focuses on the global scenario of metal pollution and its remediation through biochar activation using earthworms. The earthworms and biochar can produce "vermibiochar" which is capable of reducing the metal ions from contaminated water and soils. The vermifiltration can be a suitable technology for metal removal from wastewater/effluent. Thus, the biochar has a trick of producing entirely new options at a time when vermifiltration and other technologies are least expected. Further attention to the biochar-assisted vermifiltration of different sources of wastewater is required to be explored for the large-scale utilization of the process.

Unveiling the Efficiency of Psychrophillic Aporrectodea caliginosa in Deciphering the Nutrients from Dalweed and Cow Manure with Bio-Optimization of Coprolites

There is an immense demand for vermicomposting employing psychrophilic vermiculture (Aporrectodea caliginosa) for management of wastes under the Himalayan ecosystem. Dalweed (weeds from the world-famous urban Dal Lake) and cow manure (CM) are cheaply and abundantly available bio resources in Kashmir valley. Dalweed (DW), disposed of in the heart of the city, ascribes unpleasant effects on tourism and the natural ecosystem. Initial substrate mixtures of DW and CM with different ratios (CM100, DW100, CM80:DW20, CM60:DW40, CM40:DW60 and CM20:DW80) and castings harvested were analyzed for the following parameters: pH, TOC, TN, NO3- P, K, Fe, Zn, C:N, C:P, and C:S ratio. The results of a 56day study revealed in consistency and disparity towards the bio-optimization of coprolites depending upon the type of waste residue and mixture ratio used. Treatments with medium to low dalweed residues (CM60:DW40 followed by CM80:DW20) were found to be optimum and significantly primed chemical properties of castings using A. caligenosa. C:N, C:P, and C:S ratios showed a non-linear response with maximum decrease in C:N ratio by 35%, C:P ratio by 38% in CM100, and C:S ratio by 67% in DW100. Humification ratio, humification index, and percent humic acids were changed across all the treatments with the highest respective values of 21.33 ± 1.05, 11.33 ± 0.76, and 47.83 ± 0.76 for CM60:DW40. Results also showed that the earthworm population and biomass significantly increased with the highest respective increments of 57.53% and 74.88% in CM60:DW40 over initial values. Moreover, the highest number of cocoons (95.67 ± 1.17) were recorded within CM60:DW40 and the lowest in the control (43.33 ± 1.53). Dehydrogenase and fluorescein diacetate activities were inconsistent with the highest in CM40:DW60 (64.64%) and CM20:DW80 (63.54%) respectively over the initial substrates, while highest urease activity (74.40%) was observed from CM100. The results highlight the role of A. caliginosa in sustainable transformation of CM and DW with insightful, beneficial, and priming impacts on castings for its agronomic value.

Effects of organic loading rate and temperature fluctuation on the microbial community and performance of anaerobic digestion of food waste

Semi-continuous anaerobic fermentation of food waste was carried out using a solar-assisted heat reactor to explore effects of temperature fluctuation and organic loading rate (OLR: 2.0, 4.0, 6.0, 7.0 kg/(m³ day)VS on the reactor performance and microbial community structure. The results showed that the best methane production was achieved when OLR was 6.0 kg/(m³ day)VS because the reactors did not operate stably at 7.0 kg/(m³ day)VS. Compared with fluctuation of fermentation temperature, methane production at stable fermentation temperature increased by 21.72%, but higher power consumption occured. The results of high-throughput sequencing showed that OLR played a decisive role in succession of microbial community structure, while temperature fluctuation was more likely to affect microbial activity. When OLR was lower than 4.0 kg/(m³ day)VS, aceticlastic methanogens Methanosaeta were the dominant bacteria, while at 6.0 kg/(m³ day)VS, relative abundance of hydrogenotrophic methanogens Methanoregula and Methanospirillum increased.

Nutrient recovery from pineapple waste through controlled batch and continuous vermicomposting systems

The largest portion of pineapple peels and pulp generated from production points is disposed of haphazardly contributing to a number of environmental and health challenges. However, these wastes contain valuable plant nutrients that could be recovered to boost soil fertility, and increase agricultural production. This study evaluated the variation in physico-chemical parameters in batch and continuous vermicomposting systems as potential pathways for nutrient recovery from pineapple waste. The study compared the efficiency of waste reduction and nutrient recovery for batch (B), and continuous (C) vermicomposting systems during a 60-day period. The substrates were pineapple peels (PW), and cattle manure (CM) fed in a ratio of 4:1 (w/w). Control reactors were fed with 100% CM in both the feeding modes. Results indicated that waste degradation was 60%, and 54% while earthworm biomass increased by 57% and 129% for BPW, and CPW, respectively. pH significantly decreased with time in both systems. Total phosphorous increased with vermicomposting time with that of B being significantly higher than C systems. Nitrogen, potassium, and sodium significantly increased in the control experiments while the three elements significantly reduced for BPW, and CPW owing to high leachate production in the latter. The N, P, K, and C retention in vermicompost was 24.2%, 90.4%, 67.5%, 41.1%, and 32.6%, 91.2%, 79.3%, 46.1%, for BPW and CPW, respectively. Continuous systems produced higher earthworm biomass and retained more nutrients in vermicompost than batch systems, and can therefore, be recommended as better systems for pineapple waste vermicomposting.

Cleaner production of agriculturally valuable benignant materials from industry generated bio-wastes: A review

Bio-wastes from different agro-based industries are increasing at a rapid rate with the growing human population's demand for the products. The industries procure raw materials largely from agriculture, finish it with the required major product, and produce huge bio-wastes which are mostly disposed unscientifically. This creates serious environmental problems and loss of resources and nutrients. Traditional bio-wastes disposal possess several demerits which again return with negative impact over the eco-system. Anaerobic digestion, composting, co-composting, and vermicomposting are now-a-days given importance due to the improved and modified methods with enhanced transformation of bio-wastes into suitable soil amendments. The advanced and modified methods like biochar assisted composting and vermicomposting is highlighted with the updated knowledge in the field. Hence, the present study has been carried to compile the effective and efficient methods of utilizing industry generated bio-wastes for circularity between agriculture - industrial sectors to promote sustainability.

Centrality of cattle solid wastes in vermicomposting technology - A cleaner resource recovery and biowaste recycling option for agricultural and environmental sustainability

The current review reports the importance and significance of cattle solid waste in vermicomposting technology concerning biowaste pollution in the environment. Needy increasing population evokes livestock production resulting in the massive generation of livestock wastes, especially cattle dung. Improper disposal and handling of biowastes originating from agriculture, industries, forests, rural and urban areas lead to nutrient loss, environmental pollution and health risks. Among the organic waste disposal methods available, vermicomposting is regarded as an environmentally friendly technology for bioconversion of agricultural, industrial, rural and urban generated organic solid wastes which are serving as reservoirs of environmental pollution. In vermicomposting of organic wastes, cattle dung plays a central role in mineralization, nutrient recovery, earthworm and microbial activity leading to vermifertilizer production. Even though the vermicomposting studies use cattle dung invariably as an amendment material, its importance has not been reviewed to highlight its central role. Hence, the present review mainly emphasizes the key role played by cattle dung in vermicomposting. Vermiconversion of cattle dung alone and in combination with other biowaste materials of environmental concern, mechanisms involved and benefits of vermicompost in sustainable agriculture are the major objectives addressed in the present review. The analysis reveals that cattle dung is indispensable amendment material for vermicomposting technology to ensure agricultural and environmental sustainability by reducing pollution risks associated with biowastes on one hand, and nutrient-rich benign vermifertilizer production on the other hand.

Using milk vetch (Astragalus sinicus L.) to promote rice straw decomposition by regulating enzyme activity and bacterial community

The present study determined the dynamic changes of enzyme activity and bacterial community in rice straw (RS) and milk vetch (MV) co-decomposing process. Results showed that mixing RS and MV promoted decomposition. The mixture enhanced β-glucosidase and β-cellobiohydrolase activities relative to its monospecific residue during the mid-late stage of decomposition. The mixture enhanced Enterobacteriaceae (monosaccharide decomposing bacteria) abundance during the initial stage of decomposition, and the abundance of Hydrogenispora, Bacteroides, Ruminiclostridium, and Acidobacteriaceae that could hydrolyze fiber during the mid-late stage of decomposition relative to single RS and MV, respectively, which would benefit mixture decomposition. Furthermore, more interconnected and competitive relations existed between the bacteria in the mixture. These results indicated that mixing RS and MV promoted residue decomposition by increasing hydrolytic enzyme activities and changing bacterial community. This study concluded that co-incorporating RS and MV may be recommended as a promising practice for the efficient utilization of RS resources.

Precomposting and green manure amendment for effective vermitransformation of hazardous coir industrial waste into enriched vermicompost

Vermitransformation of coir pith (CP) into enriched vermifertilizer has been achieved by amending a green-manure plant, Sesbania sesban (SS) for the first time, and cow dung (CD) in five different combinations: T1_(1:0:1), T2_(4:3:3), T3_(5:3:2), T4_(5:4:1) and T5_(1:1:0). The substrates were 28 days precomposted with Pleurotus sajor-caju followed by 50 days vermicomposting with Eisenia fetida and Eudrilus eugeniae. Results showed a significant reduction in cellulose, lignin, organic carbon, C/N ratio, C/P ratio and an increase in plant nutrients compared to control. The fertilization index and efficiency of nutrient recovery rate were higher in SS and CD amended CP vermicompost, with a maximum in T2_(4:3:3) for E. fetida and T3_(5:3:2) for E. eugeniae. The activity of dehydrogenase, urease and cellulase, and phytotoxicity assays further revealed vermicompost stability. The study concludes that T2_(4:3:3) and T3_(5:3:2) combinations respectively for E. fetida and E. eugeniae is suitable for vermitransformation of CP into enriched vermicompost.

Earthworm intervened nutrient recovery and greener production of vermicompost from Ipomoea staphylina - An invasive weed with emerging environmental challenges

The invasive weed, Ipomoea staphylina (IS) with cow dung (CD) and mushroom spent straw (MS) in four different combinations (IS:CD:MS), V1 (1:1:0), V2 (2:1:1), V3 (1:0:1) and V4 (1:1:1) were pre-decomposed for 21 days followed by 50 days vermicomposting using Eudrilus eugeniae in triplicates in order to alleviate and to utilize the weed biomass in an environment-friendly manner. The contents of organic matter, organic carbon, cellulose, lignin, C/N and C/P ratios showed a decrease, while electrical conductivity, total NPK, calcium, sodium, and nitrate-nitrogen showed a significant increase in vermicompost over control. Water-soluble organic carbon to organic nitrogen ratio and C/N ratio in V1 (0.52 and 17.55) and V4 (0.43 and 16.56), respectively, were in conformity with the maturity of vermicomposts. Scanning electron micrographs of the end products clearly showed more fragmented, fine, and porous particles in vermicompost. Copper, chromium, cadmium, lead, and zinc in vermicomposts were below the permissible limits. Dehydrogenase, acid phosphatase, alkaline phosphatase, cellulase, and protease activities were significantly higher in V4 than other treatments, implying the role of MS and CD addition during vermicomposting. Though V3 combination supported worm biomass, V4 combination was found to favor the fecundity of Eudrilus eugeniae. Results reveal that 1:1:1 combination of SI + CD + MS (V4) is suitable for utilizing the weed biomass for vermicompost production and nutrient recovery. From the biomass of environmentally problematic weed, Ipomoea staphylina, nutrient-rich vermicompost can be produced through vermitechnology for sustainable environmental management and agriculture.

Nutrient recovery and vermicompost production from livestock solid wastes with epigeic earthworms

The aim of this work was to study nutrient recovery and vermicompost production from livestock solid wastes of indigenous and exotic cow breeds with epigeic earthworms. Fourteen days pre-decomposed dung of Vechur native (CD1) and exotic Jersey (CD2) breeds were vermicomposted with Perionyx excavatus and Eudrilus eugeniae for 45 days (Cycle I) and 90 days (Cycle II) including respective controls without earthworms. Vermicomposts from CD1 and CD2 substrates during Cycle I and II showed increase in NPK, Ca and micro-nutrients (P < 0.05); whereas, pH, total organic carbon, C/N and C/P ratios disclosed decrease (P < 0.05) over initial levels for both the earthworms. E. eugeniae was found efficient in vermicomposting cattle solid wastes in 45 days and CD1 yielded nutrient rich vermicompost. The study concludes that Cycle I is suitable for nutrient recovery and vermicompost production, in addition to mass multiplication of earthworms in Cycle II.

Vermicomposting of invasive weed Ageratum conyzoids: Assessment of nutrient mineralization, enzymatic activities, and microbial properties

Ageratum conyzoids biomass was vermicomposted with cow dung in 25 (T₂₅), 50 (T₅₀), and 75 (T₇₅) % (v/v) ratios and changes in physicochemical characteristics, enzymatic activities (proteases, dehydrogenases, β-galactosidase and phosphatases), and microbial population (bacterial, fungal, and actinomycetes) was recorded. Vermicomposting caused a decrease in pH, OC_total (27.3-35.3%), but an increase in N_total (59.6-69.9%), P_aval (53.8-148.7%), K_total (32.2-92.43%), and Ca_total (25.5-55.3%). The peaked enzymatic activities were recorded between 5 and 15 d. T₅₀ and T₇₅ showed the highest fold increase in bacteria (2.09-to-2.51), fungi (1.48-to-2.41), actinomycetes (1.52-to-1.79) population. The maximum biomass (883.67-1480 mg), cocoon production (85.33-145.33), and population build-up in earthworm were recorded in setups with a high content of Ageratum. Germination index (>80%) and soil respiration rate suggested the non-toxic impact of vermicomposted Ageratum. Results indicate that Ageratum could be biotransformed into toxic-free manure through vermitechnology.

Vermicomposting of duckweed (Spirodela polyrhiza) by employing Eisenia fetida: Changes in nutrient contents, microbial enzyme activities and earthworm biodynamics

This study investigated the vermicomposting of duckweed (DW) mixed with cow dung in 25 (T₂₅), 50 (T₅₀), 75 (T₇₅), 100% (T₁₀₀) ratio using Eisenia fetida under a 35 d trail. Decrease in pH, organic carbon (33.54-38.25%), C/N ratio (43.6-56.6%), but increase in total N (18.2-42.4%), P_aval (137-187%), and TK (7.76-79.4%) was recorded. Macro-elements (Mg, Fe, Zn, Mn, and Cu) also showed a many-fold increase in vermicomposts. T₅₀ and T₇₅ showed the highest mineralization rates. Activities of enzymes (proteases; dehydrogenases; β-galactosidase; acid phosphatase; and alkali phosphatases) and soil respiration rate was also higher in DW-rich waste mixtures. Seed bioassay test indicates the high agronomic application of DW-based vermicomposts. High earthworm biomass (975-1395 mg) and fecundity rate (1.53-4.07 cocoons worm^-1) was recorded in all vermi-setups suggesting the suitability of DW as a substrate for E. fetida culture.

Earthworms and vermicompost: an eco-friendly approach for repaying nature's debt

The steady increase in the world's population has intensified the need for crop productivity, but the majority of the agricultural practices are associated with adverse effects on the environment. Such undesired environmental outcomes may be mitigated by utilizing biological agents as part of farming practice. The present review article summarizes the analyses of the current status of global agriculture and soil scenarios; a description of the role of earthworms and their products as better biofertilizer; and suggestions for the rejuvenation of such technology despite significant lapses and gaps in research and extension programs. By maintaining a close collaboration with farmers, we have recognized a shift in their attitude and renewed optimism toward nature-based green technology. Based on these relations, it is inferred that the application of earthworm-mediated vermitechnology increases sustainable development by strengthening the underlying economic, social and ecological framework.

Bacterial community composition of vermicompost-treated tomato rhizospheres

Vermicompost application has been shown to promote plant growth, alter the rhizosphere microbiome, and suppress plant pathogens. These beneficial properties are often attributed to the activity of vermicompost-associated microorganisms. However, little is known about the microbial shifts that occur in the rhizosphere after vermicompost application. To better understand the impact of vermicompost treatments on the assembly of rhizosphere bacterial communities, 16S rDNA communities of vermicompost and rhizospheres of each peat- and soil-grown tomatoes were profiled after conventional fertigation, irrigation without additional nutrients, and addition of three different vermicompost-extracts. The full dataset consisted of 412 identified genera, of which 317 remained following stringent quality filtration. Tomato rhizosphere microbiome responses to treatments were complex and unique between peat and soil growth substrates. Direct colonization of vermicompost-origin taxa into rhizospheres was limited, with genera Photobacterium and Luteimonas colonizing peat rhizospheres, genera Truepera, Phenylobacterium, and Lysinibacillus colonizing soil rhizospheres, and genus Pelagibius appearing in both soil and peat rhizospheres. Further patterns of differential abundance and presence/absence between treatments highlight vermicompost-mediated effects on rhizosphere microbiome assembly as an interplay of rhizosphere medium, direct colonization of vermicompost-origin taxa and vermicompost-induced shifts in the rhizosphere microbial community. This exploratory analysis is intended to provide an initial look at 16S community composition of vermicompost and the effects of vermicompost treatment on the rhizosphere microbiome assembly to highlight interactions of potential merit for subsequent investigations.