Earthworm production in cattle dung vermicomposting system under different stocking density loads

Introduction  

This work illustrates the productivity of composting earthworm Perionyx excavatus under different stocking density (in milligrams biomass per cubic centimeter vermibed space) gradients in cattle dung decomposing system.     

Water quality assessment of river Hindon at Ghaziabad, India: impact of industrial and urban wastewater

Spontaneous combustion on industrial-scale stockpiles causes environmental problems and economic losses for the companies consuming large amounts of coal. In this study, an effective monitoring and prediction system based on internet was developed and implemented to prevent losses and environmental problems. The system was performed in a coal stockpile with 5 m width, 10 m length, 3 m height, and having 120 t of weight. The inner temperature data of the stockpile was recorded by 17 temperature sensors placed inside the stockpile at certain points. Additionally, the data relating to the air temperature, air humidity, atmospheric pressure, wind velocity, and wind direction that are the parameters affecting the coal stockpile were also recorded. The recorded values were analyzed with artificial neural network and Statistical modeling methods for prediction of spontaneous combustion. Real-time measurement values and model outputs were published with a web page on internet. The internet-based system can also provide real-time monitoring (combustion alarms, system status) and tele-controlling (Parameter adjusting, system control) through internet exclusively with a standard web browser without the need of any additional software.     

Metal remediation from partially composted distillery sludge using composting earthworm Eisenia fetida

Distillery sludge, a sugar industry byproduct, has been recommended widely as a potential soil conditioner, but high concentrations of metals limit its continuous use for field crops. In this study we tested the feasibility of earthworm Eisenia fetida (Savigny) in removing metals (Fe, Cu, Zn, Pb) from sludge through vermitechnology. The transfer of metals during the vermicomposting process was also estimate in terms of total metal contents in vermicomposted sludge and earthworm tissues. The sludge processed by worms showed a significant reduction in concentration of metals: Zn (20.5-43.8%), Fe (23.6-34.0%), Mn (18.0-45.7%) and Cu (29.0-58.1%), at the end. The metal reduction in sludge was directly related to the bioaccumulation of metals in the tissues of composting earthworms. The inoculated earthworms showed a considerable level (dry wt basis) of Zn (103.7-143.3 mg kg(-1)), Fe (87.2-146.5 mg kg(-1)), Mn (83.7-138.6 mg kg(-1)) and Cu (16.8-25.5 mg kg(-1)) in their tissues. A higher range of bioconcentration factors (BCFs) for different metals studied further suggest the candidature of earthworm to be used effectively for removal of metals form industrial sludges. The obtained vermicomposts form different vermireactors were rich in nutrients. The feasibility of earthworms to mitigate the metal toxicity and to enhance the nutrient profile in sludge might be useful in sustainable land restoration practices at low-input basis. The ranges of metals in end product were within the standards recommended by different agencies.     

Seasonal dynamics in earthworm density, casting activity and soil nutrient cycling under Bermuda grass (Cynodon dactylon) in semiarid tropics, India

This work illustrates the result of a study on earthworm abundance, seasonal population dynamics and casting activities under Bermuda grass cover in a semiarid tropical part of Rajasthan, India. The earthworm abundance and their casting activities showed the drastic variation during different seasons. The maximum density (individual m^?2) of earthworms was recorded in autumn (87.0?±?7.2) and minimum in winter (5.3?±?3.2) season in grassland. There was also variation in temperature and moisture of canopy soil in different seasons of the experimental year. The casting activities of earthworm also showed variations among different seasons. The maximum cast production rate was recorded during autumn (690.0?±?78.0?g?m^?2) while in winter (17.3?±?5.1?g?m^?2), earthworms showed the lowest cast production rate. The chemical composition of worm casts and parental soil layers (topsoil: 0?C10?cm depth and subsoil: 10?C25?cm depth) in grassland ecosystem was also monitored. The earthworm casts collected during winter showed the maximum level of total N (0.890?g?kg^?1), available P (0.373?g?kg^?1), exchangeable K (0.835?g?kg^?1), exchangeable Ca (7.10?g?kg^?1) and exchangeable Mg level (5.93?g?kg^?1) while the maximum organic C content (5.27?g?kg^?1) was recorded in surface casts deposited in rainy season. The level of major soil nutrients was also high in worm casts than parental soil and indicates the earthworm-mediated nutrient mineralization and organic matter transformation. Results thus clearly suggest the major role of earthworm in soil nutrient transformation in semiarid ecosystem.     

EDTA-enhanced phytoremediation of contaminated calcareous soils: heavy metal bioavailability,extractability, and uptake by maize and sesbania

Natural and chemically enhanced phytoextraction potentials of maize (Zea mays L.) and sesbania (Sesbania aculeata Willd.) were explored by growing them on two soils contaminated with heavy metals. The soils, Gujranwala (fine, loamy, mixed, hyperthermic Udic Haplustalf) and Pacca (fine, mixed, hyperthermic Ustollic Camborthid), were amended with varying amounts of ethylenediaminetetraacetic acid (EDTA) chelating agent, at 0, 1.25, 2.5, and 5.0 mM kg^?1 soil to enhance metal solubility. The EDTA was applied in two split applications at 46 and 60 days after sowing (DAS). The plants were harvested at 75 DAS. Addition of EDTA significantly increased the lead (Pb) and cadmium (Cd) concentrations in roots and shoots, uptake, bioconcentration factor, and phytoextraction rate over the control. Furthermore, addition of EDTA also significantly increased the soluble fractions of Pb and Cd in soil over the controls; the maximum increase of Pb and Cd was 13.1-fold and 3.1-fold, respectively, with addition of 5.0 mM EDTA kg^?1soil. Similarly, the maximum Pb and Cd root and shoot concentrations, translocation, bioconcentration, and phytoextraction efficiency were observed at 5.0 mM EDTA kg^?1 soil. The results suggest that both crops can successfully be used for phytoremediation of metal-contaminated calcareous soils.     

Bioremediation of aerobically treated distillery sludge mixed with cow dung by using an epigeic earthworm Eisenia fetida

The potential of the epigeic earthworm Eisenia fetida to stabilize sludge␣(generated from a distillation unit of the sugar industry) mixed with cow dung, in different proportions i.e. 20% (T₁), 40% (T₂), 60% (T₃) and 80% (T₄) has been studied under laboratory conditions for 90 days. The␣ready vermicompost was evaluated for its’ different physico-chemical parameters using standard methods. At the end of experiment, all vermibeds expressed a significant decrease in pH (7.8–19.2%) organic C (8.5–25.8%) content, and an increase in total N (130.4–170.7%), available P (22.2–120.8%), exchangeable K (104.9–159.5%), exchangeable Ca (49.1–118.1%), and exchangeable Mg (13.6–51.2%) content. Overall, earthworms could maximize decomposition and mineralization efficiency in bedding with lower proportions of distillery sludge. DTPA extractable metal reduction in substrate was recorded between the ranges of 12.5–38.8% for Zn, 5.9–30.4% for Fe, 4.7–38.2% for Mn and 4.5–42.1% for Cu. Maximum values for the mean individual live weight (809.69 ± 20.09 mg) and maximum individual growth rate (mg wt. worm⁻¹ day⁻¹) (5.81 ± 0.18) of earthworms was noted in T₁ treatment, whereas cocoon numbers (69.0 ± 7.94) and individual reproduction rate (cocoon worm⁻¹ day⁻¹) (0.046 ± 0.002) was highest in T₂ treatment. Earthworm mortality tended to increase with increasing proportion of distillery sludge, and maximum mortality in E. fetida was recorded for the T₄ (45.0 ± 5.0) treatment. Results indicate that vermicomposting might be useful for managing the energy and nutrient rich distillery sludge on a low-input basis. Products of this process can be used for sustainable land restoration practices. The feasibility of worms to mitigate the toxicity of metals also reduces the possibility of soil contamination, which has been reported in earlier studies during direct field application of industrial wastes.