Earthworm Weight Research Articles

Amelioration and degradation of pressmud and bagasse wastes using vermitechnology

This study evaluated the amelioration of pressmud (PM) and bagasse (BG) wastes by the vermiremediation process. The wastes were spiked with cattle dung (CD) in different concentrations to find out the best proportion supporting maximum earthworm growth and nutrients availability. The highest growth rate was observed in PMBG50 (282.2mg/d/worm) feed mixture. Response surface design of earthworm growth parameters enumerated best concentration of wastes in CD with maximum value of 21.81% for earthworm number, 30.86% for earthworm weight, 27.09% for cocoons, 29.71% for hatchlings and 34.0% for hatchlings weight. Vermicomposting enhanced nutrient parameters like pH (6–8%), total kjeldahl nitrogen (19–48%), total phosphorus (9–67%), total calcium (13–111%), while decrease in total organic carbon (14–32%), electrical conductivity (21–30%), C:N ratio (36–51%), total potassium (9–19%) and total sodium (3–21%). Heavy metals in the final products were found to be under safe limits. SEM micrographs were more fragmented which indicated maturity and stability.

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.

Effects of the herbicides benfluralin, metribuzin and propyzamide on the survival and weight of earthworms (Octodrilus complanatus)

Extended pesticide use might be of high risk for several non-target organisms like earthworms. Herbicides represent a major part of the total pesticides used; however, their effects on soil organisms have been only partially studied. The effects of the herbicides benfluralin, metribuzin and propyzamide at different rates on the survival and weight of earthworms (Octodrilus complanatus) were determined and compared in this study. Our results revealed significant effects of benfluralin, metribuzin and propyzamide on growth and survival of earthworms. Moreover, there was a significant effect of herbicide rate and time after treatment. For several herbicides, the highest weight reduction was obtained for double the recommended rate and was up to 70% compared to the untreated soil. This study highlights the importance of not exceeding the recommended rates of herbicides, while further studies in a range of conditions are certainly required.

Treatment of textile milldye sludge by vermicomposting using Perionyx excavatus species

The accumulation of solid waste sludge from Textile dye sludge causes a great problem in its safe disposal. Perionyx excavatus were cultured under laboratory condition with 60-80%moisture in mud pot container following with the mixing ratio of TMS (Textile Mill Sludge) + SD(Sawdust) designated as X (1:1) respectively add inoculums (EM) Effective microorganisms and (CD) Cow dung were also used in the above ratio. Once in 15days upto 90days number of hatchling, worm growth rate and the weight of earthworms were determined and analysed statistically. On the basic of the efficiency of four treatments with control condition, (EM) separately, (CD) separately and (EM+SD) combined together were analysed to support the reproduction and growth of Perionyx excavatus has been done. The growth rate, weight gain, and hatchling production observed in the mixed ratio of TMS+SD (1:1) ratio with the above treatments were determined and better combination of mixed ratio with appropriated inoculums was determined. The mixed of TMS+SD+(EM+CD) gave high growth rate, weight gain and hatchling production of selected vermiculture Perionyx excavatus. Hence TMS in combination SD in (1:1ratio) can be used for vermiculture.

Histopathological and molecular effects of microplastics in Eisenia andrei Bouché

The ocean has been assumed as the main sink of microplastics (MPs), however, soils may also receive MPs from different sources and through different pathways, which may affect the biota and their role in soil functions. To the best of our knowledge, only one study, until now, reported the effects of MPs on the survival and fitness of soil organisms (Lumbricus terrestris). In our study, epigeic earthworms, of the species E. andrei, were exposed to different concentrations of MPs (0, 62.5, 125, 250, 500 and 1000 mg/kg soildw) in an OECD artificial soil and tested for reproduction, survival and growth of adults, following a standard protocol. The size of the polyethylene MPs to which earthworms were exposed ranged between 250 and 1000 μm. No significant effects were recorded on survival, number of juveniles and, in the final weight of adult earthworms after 28d of exposure, to the different concentrations of MPs. Nevertheless, FTIR-ATR of earthworms and histopathological analysis of the gut provided evidences of damages and immune system responses to MPs.

Effect of chlorpyrifos on survival, growth and reproductive performance of Eudrilus eugeniae (Kinberg)

The present laboratory study was conducted to determine the effect of chlorpyrifos on growth and reproduction of the earthworm Eudrilus eugeniae. Chlorpyrifos was mixed with soil substrate at four different dose formulations i.e. D1 (2.5ml/1000ml); D2 (5.0ml/1000ml); D3 (7.5ml/1000ml); D4 (10.0ml/1000ml). Soil substrate withoutchlorpyrifos served as control. Growth and survival rates were determined till four weeks and effects on reproduction are assessed after eight weeks of exposure. A non significant decrease (p > 0.05) was observed in body weight of earthworms which was recorded on day 1, 2, 3, 7, 10 and 14. A dose dependent effect on cocoon production and survivability of hatchlings was observed in all treated groups. The effect of chlorpyrifos on life cycle of earthworm was more in dose D3 (54.25 days) when compared to control (28.75 days) while no worm survived in D4 dose. The present study revealed that chlorpyrifos at high dose levels(7.5ml/1000ml and 10.0ml/1000ml) affect the reproduction and growth of earthworms, primary bioindicators of soil fauna, whereas the base dose (5.0ml/1000ml) may be considered as safe for soil applications.

Impact of apple orchard management strategies on earthworm (Allolobophora chlorotica) energy reserves

To assess the effects of agricultural management strategies on earthworm energy reserves (glycogen and lipids), 16 apple orchards under different strategies (organic, Integrated Pest Management (IPM), conventional and abandoned) were selected. Soil samples and 10 adults of the most common earthworm species (Allolobophora chlorotica) were sampled in each orchard. The glycogen and lipid concentrations in the earthworms did not correlate with any soil characteristics and no significant differences in earthworm weight were observed between strategies. However, significantly lower glycogen and lipid concentrations were found in earthworms inhabiting conventional orchards, with a decrease of 45 and 63% compared to organic and abandoned orchards respectively. Earthworms from IPM orchards had intermediate values. This suggests that pesticide usage leads to the observed decrease of energy reserves in A. chlorotica. Thus the reduced insecticide use in IPM compared to conventional strategies, albeit significant, appears to be too small to result in pronounced effects on energy reserves in this earthworm species.

The effect of precomposted sewage sludge mixture amended with biochar on the growth and reproduction of Eisenia fetida during laboratory vermicomposting

The obtained results showed that the addition of biochar to the mixture of sewage sludge and wheat straw prior to composting facilitated the growth and reproduction of Eisenia fetida during laboratory vermicomposting of this mixture. After 4 weeks of vermicomposting the average number of produced cocoons in the mixtures amended with biochar increased by 13% for SS+ST+4%B and 66% for SS+ST+8%B. Also, the number of juvenile earthworms was higher in the mixtures amended with biochar. However, the total weight of earthworms declined with the depletion of organic matter after 18 weeks of the experiment. Amending sewage sludge mixtures with biochar for vermicomposting resulted in higher reproduction rates, and thus could allow faster and more efficient conversion of sewage sludge into vermicompost.

Lethal and sub-lethal effects of five pesticides used in rice farming on the earthworm Eisenia fetida

The toxicity of five pesticides typically used in rice farming (trichlorfon, dimethoate, carbendazim, tebuconazole and prochloraz) was evaluated on different lethal and sub-lethal endpoints of the earthworm Eisenia fetida. The evaluated endpoints included: avoidance behaviour after an exposure period of 2 days; and mortality, weight loss, enzymatic activities (cholinesterase, lactate dehydrogenase and alkaline phosphatase) and histopathological effects after an exposure period of 14 days. Carbendazim was found to be highly toxic to E. fetida (LC50=2mg/kg d.w.), significantly reducing earthworm weight and showing an avoidance response at soil concentrations that are close to those predicted in rice-fields and in surrounding ecosystems. The insecticide dimethoate showed a moderate acute toxicity (LC50=28mg/kg d.w.), whereas the rest of tested pesticides showed low toxicity potential (LC50 values above 100mg/kg d.w.). For these pesticides, however, weight loss was identified as a sensitive endpoint, with NOEC values approximately 2 times or lower than the calculated LC10 values. The investigated effects on the enzymatic activities of E. fetida and the observed histopathological alterations (longitudinal and circular muscle lesions, edematous tissues, endothelial degeneration and necrosis) proved to be sensitive biomarkers to monitor pesticide contamination and are proposed as alternative measures to evaluate pesticide risks on agro-ecosystems.

草粉与猪粪不同配比对蚯蚓生长的影响

动物粪便养殖蚯蚓对开发生态循环养殖和海南国际旅游岛建设具有重要作用。海南地区蚯蚓养殖业正处于新兴发展时期，提高蚯蚓的成活率与整体增重成为蚯蚓生产的重要任务。本课题将动物粪便与土壤及草粉经过合适的配比发酵后培养蚯蚓，观察蚯蚓的成活率及增重情况，结果表明：猪粪便、土壤和草粉按45%:45%:10%的比例制成饲养蚯蚓的基料，蚯蚓的成活率最高达到81.7%，增重量也最大，在生产上可推广应用。 Production of earthworms with animal manure provides a good alternative to benign agro-eco- logical circulation, which plays an important role in the construction of agro-ecological circulation and international tourism island of Hainan. Vermiculture in Hainan is a welcomed new industry. How to improve the survival rate and the overall weight of earthworms is an urgent problem demanded in earthworm production. Using the combination of animal manure, soil and grass powder with appropriate ratio for fermentation to feed earthworms was a good try in this article. The results showed that earthworms fed on mixtures of pig manure, soil and grass powder, had the highest survival rate (81.7%) and the highest weight of increment. And the survival rate and weight of earthworms were increased to the demand. The mixtures of pig manure, soil and grass powder were fermented together with the proportion of 45%:45%:10%. Taken together, this method will be applied in the production of earthworms.

The prolonged effect of salinity on growth and/or survival of earthworm Eisenia fetida

An experiment was conducted with specimen of Eisenia fetida exposed in the laboratory for 42 days using manure irrigated with NaCl solution. NaCl solutions were prepared with distilled water in the following concentrations: 0, 1,170, 2,340, 3,510 and 4,680 mgL−1 with electrical conductivity of 0, 2, 4, 6 and 8 dS/m respectively. Mortality and change in weight were assessed at day 3, 15, 21, 27, 33, 39 and 42. It is concluded that salinisation negatively affects survival and growth of earthworms. Result showed that salinity statistically had a significant influence on weight of earthworms (P < 0.05). The calculated LC50 and EC50 for mortality and growth after 42 days was 1.83 dS/m (1,069 mg/lit) and 6.82 dS/m (3,987 mg/lit) respectively.

Sublethal Toxic effects of spent Oil Based Drilling Mud and Cuttings to Earthworm Aporrectodea Longa.

Sublethal toxic effects of spent oil based drilling mud collected from an abandoned oil drilling site in Mpanak, Akwa Ibom State, Nigeria were assessed in the earthworm Aporrectodea longa . The test annelid was exposed to sub-lethal Concentration of 0ppm SPP; 62,500ppm SPP; 125, 000ppm SPP; 250,000ppm SPP and 500,000ppm SPP of drilling mud for 28 days. The procedure for the exposure was according to the Organisation for Economic Co-operation and Development (OECD) recommended method for testing chemicals No 207. There were three replicate jars per treatment and 10 earthworms per jar of soil spiked with drilling mud. Control groups were also set up. At the end of the exposure, bioaccumulation of the chemical constituents of the drilling mud (heavy metals and TPH) increased (p<0.01) with increase drilling mud concentration. Mean weights of earthworms increased in the 62,500 and 125,000SPP and decreased in the 250,000 and 500,000SPP. Glucose levels increased with increase in the drilling mud concentration with the exception of 62,500ppm SPP. The elevated glucose levels could be due to hyperglycemia induced by the toxicity of the drilling mud. Protein levels increased with increase in drilling mud concentration except in the 125,000ppm SPP treatment. The increase in protein content could be due to enhancement of microsomal protein synthesis prompted by the toxicity of the drilling mud to test organisms. The results of this study have shown that drilling mud and cuttings could cause serious health risk to Aporrectodea longa. The discharge of drilling mud into the terrestrial ecosystems should be discouraged. © JASEM

Ecotoxicological assessment of a dredged sediment using bioassays with three species of soil invertebrates.

The ecotoxicity of a dredged sediment from the Guanabara Bay (Rio de Janeiro, RJ, Brazil) was evaluated using reproduction tests with Eisenia andrei, Folsomia candida and Enchytraeus crypticus, and avoidance and feeding inhibition tests with Folsomia candida. The sediment was mixed with artificial soil to obtain the following doses: 1.25, 2.5, 5.0, 10.0, 20.0 and 40.0%. Lead, nickel, chromium, copper and zinc concentrations were determined in the test mixtures. In reproduction tests, E. andrei was the most sensitive species (EC50=2.94%), followed by F. candida (EC50=7.72%) and E. crypticus (EC50=10.10%). The percentage of initial weight of earthworms was significantly higher in all test concentrations compared to the control except at the highest one where earthworms biomass significantly decreased. No feeding inhibition of F. candida was observed for any test mixture and the number of organisms with a dark gut (the fed collembolans) generally increased with the increasing dose of sediment. Significant avoidance responses of F. candida were observed towards all test mixtures, however, the avoidance behaviour was the less sensitive endpoint after feeding inhibition. The results showed that chemical analysis is not sufficient to foresee toxic effects in terrestrial systems resulting from sediment disposal in soil if not complemented with an ecotoxicological evaluation.

Evaluation of Different Soil Parameters and Wild Boar (Sus Scrofa [L.]) Grassland Damage

Presented in this paper are the correlations between different soil parameters [presence of grubs, earthworms, pH, content of P2O5, K2O and organic matter (OM) in soil] and wild boar (Sus scrofa [L.]) damage to grasslands. The soil samples and damage assessments were performed at six locations in the Kočevje region, which is a densely wooded part of South East Slovenia. A significant positive correlation was discovered between the extent of damage due to wild boar rooting in grasslands and the number of grubs (r=0.73), the weight of grubs (r=0.69) and the content of P2O5 (r=0.87) in the soil. The quantity and weight of grubs in soil were significantly influenced by soil pH, the content of CaCl2 (r=0.71/0.72), P2O5 (r=0.90/0.91), and OM (r=0.74/0.77); while the quantity and weight of earthworms in soil were influenced by the content of K2O (r=0.81/-0.84). A moderate yet insignificant correlation (r=0.48/0.56) was discovered between the number and weight of earthworms in soil and the extent of grassland damage. Grubs represent a more important source of protein for wild boars than earthworms; consequently, reducing the quantity of grubs in soil could minimise the extent of damage caused by boars.

Dose-dependent reactions of Aporrectodea caliginosa to perfluorooctanoic acid and perfluorooctanesulfonic acid in soil

As a consequence of their widespread use, e.g. as protective coatings for fabrics, and their resistance to thermal and biological breakdown, perfluorinated compounds are increasingly found in the environment, but little is known about their ecotoxicological properties. A 40-day microcosm experiment was carried out to examine the effects of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) on the endogeic geophagus earthworm Aporrectodea caliginosa, its survival and feeding on soil organic C and microbial biomass C. Three levels of concentration (1, 100, and 500mgkg−1) were chosen. The lowest represented the maximum found in sediments and soils and the other two are extreme concentrations that might occur in pollution hotspots and that have been shown to poison organisms. Earthworms promoted the production of CO2 and decreased microbial biomass C in soil, regardless of the presence of PFOA or PFOS. Both compounds significantly decreased the surviving numbers and dry weight of earthworms at concentrations of 100mgkg−1. No earthworms survived at PFOA and PFOS concentrations of 500mgkg−1. At concentrations of 1mgkg−1, no negative effects were observed. The δ13C values of A. caliginosa did not differ between treatments. In contrast, the δ15N values were significantly increased after adding 1mgkg−1 of PFOA, reflecting elevated portions of soil-derived N in the earthworm tissue. In contrast, these portions of soil-derived N were lower in the earthworms after addition of 100mgkg−1 of PFOA and PFOS. In conclusion, extreme concentrations of PFOA and PFOS negatively affected endogeic A. caliginosa, whereas a concentration of 1mgkg−1 of PFOA and PFOS was related to an increased uptake of soil N by the earthworms.

Influence of the Activity of Allobophora molleri in Microbial Activity and Metal Availability of Arsenic-Polluted Soils

We investigate the use of Allolobophora molleri as a biomarker of arsenic (As)-polluted soils and study the influence of A. molleri on the metabolic activity and microbial biodiversity of soil polluted with As. Because there are no experimental data available regarding the effect of the pollutant rate of As on A. molleri, we determined the LC₅₀ that was 143.5 mg As kg(-1). Sodium arsenite was added at two rates, equivalent to 143.5 and 71.8 mg As kg(-1) soil, to a soil that was then maintained with and without worms for 120 days. In addition, a nonpolluted soil without and with earthworms was used as the control. The As concentration in the soil was measured after 7 and 120 and the worm weight and As concentration after 120 days of exposure. Soil enzymatic activities and the structure of the soil microbial community, by analysis of phospholipid fatty acids, were determined. At the end of the experiment, the highest earthworm As contents were found in soils polluted with the highest rate of As. Earthworm weights significantly decreased in soil polluted with 143.5 or 71.8 mg As kg(-1), by 49.9 and 29.8% of initial weight, because the worm consumption rate decreased. These results suggest that A. molleri can be used as a good biomarker of the As toxicity. The As available fraction decreased in polluted soil with worms because the metal was accumulated in worm tissues. However, this assimilation was lower than other worms such as L. rubbellus or L. terrestris. Soil enzymatic activities were decreased in As-polluted soils but were increased significantly by the presence of earthworms. The earthworms modified the soil microbial diversity. In this respect, A. molleri significantly increased (p < 0.05) the bacterial and fungal populations. Soil As pollution decreased microbial biodiversity but to a lesser extent in the presence of A. molleri.

Responses of earthworm to aluminum toxicity in latosol

Excess aluminum (Al) in soils due to acid rain leaching is toxic to water resources and harmful to soil organisms and plants. This study investigated adverse impacts of Al levels upon earthworms (Eisenia fetida) from the latosol (acidic red soil). Laboratory experiments were performed to examine the survival and avoidance of earthworms from high Al concentrations and investigate the response of earthworms upon Al toxicity at seven different Al concentrations that ranged from 0 to 300 mg kg(-1) over a 28-day period. Our study showed that the rate of the earthworm survival was 100 % within the first 7 days and decreased as time elapsed, especially for the Al concentrations at 200 and 300 mg kg(-1). A very good linear correlation existed between the earthworm avoidance and the soil Al concentration. There was no Al toxicity to earthworms with the Al concentration ≤ 50 mg kg(-1), and the toxicity started with the Al concentration ≥ 100 mg kg(-1). Low Al concentration (i.e., <50 mg kg(-1)) enhanced the growth of the earthworms, while high Al concentration (>100 mg kg(-1)) retarded the growth of the earthworms. The weight of earthworms and the uptake of Al by earthworms increased with the Al concentrations from 0 to 50 mg kg(-1) and decreased with the Al concentrations from 50 to 300 mg kg(-1). The protein content in the earthworms decreased with the Al concentrations from 0 to 100 mg kg(-1) and increased from 100 to 300 mg kg(-1). In contrast, the catalase (CAT) and superoxide dismutase (SOD) activities in the earthworms increased with the Al concentrations from 0 to 100 mg kg(-1) and decreased from 100 to 300 mg kg(-1). The highest CAT and SOD activities and lowest protein content were found at the Al concentration of 100 mg kg(-1). Results suggest that a high level of Al content in latosol was harmful to earthworms.

Soil conservation on road embankments using palm‐mat geotextiles: field studies in Lithuania

AbstractThe application of geotextile mats constructed from the palm leaves of Borassus aethiopum (Borassus) and Mauritia flexuosa (Buriti) was investigated in field experiments. The use of geotextiles caused improved soil moisture storage during dry summer periods on a steep (21–25°) roadside slope in Lithuania. The enhanced soil moisture under the Borassus and Buriti mats encouraged better root development of perennial grasses, increased the number and weight of earthworms and increased the dry biomass of perennial grasses by 50.5 and 18.2%, respectively, compared with a grassland control. The mean rate of water erosion from bare soil during the study period from 17/04/2007 to 11/12/2008 was 33.21 Mg/ha. The cover of palm‐mat geotextiles decreased soil losses from bare fallow soil by 94.8–91.1%. An erosion rate of 0.85 Mg/ha over this 21‐month period was measured on the slope under perennial grasses without geotextile cover. Application of geotextile cover on perennial grasses completely prevented soil erosion by water. Therefore, use of geotextiles has clear soil and water conservation benefits on industrial slopes susceptible to erosion. The use of geotextiles has multiple benefits including soil conservation, the improvement of plant growth conditions and the encouragement of earthworm populations.

Maize residue application reduces negative effects of soil salinity on the growth and reproduction of the earthworm Aporrectodea trapezoides, in a soil mesocosm experiment

We studied the effects of maize residue application on some life-cycle parameters of the earthworm Aporrectodea trapezoides in saline agricultural soils with electrical conductivity (EC) ranging from 1.58 to 7.35 dS m−1. This experiment was carried out under controlled laboratory conditions for 150 days. Results showed that soil salinity significantly affected the growth and reproduction of earthworms, decreasing survival, numbers and mean fresh weights of adults, juveniles and cocoons. Maize residue application gave a greater survival of earthworms at all salinity levels, but the differences were only significant at an EC of 7.35 dS m−1, although the mean weight of adult earthworms was significantly increased by maize residue application at all salinity levels. At an EC of 1.58 dS m−1 and 3.35 dS m−1, the application of maize residues gave significantly higher numbers of cocoons and juveniles, but in soils with 5.26 dS m−1 and 7.35 dS m−1 earthworms did not produce any cocoons over the experimental period, irrespective of maize residue application. These results indicated that maize residue application alleviated the negative effects of soil salinity on the growth and reproduction of A. trapezoides up to 3.35 dS m−1, above which maize residues only increased the growth but not on the reproduction of earthworms.

Effect of Tuber Crop Wastes/Byproducts on Nutritional and Microbial Composition of Vermicomposts and Duration of the Vermicomposting Process

A pot culture experiment on vermicomposting of cassava and sweet potato wastes/byproducts was conducted for March–May (season I) and June–August (season II) during 2010 at the Regional Centre of Central Tuber Crops Research Institute, Bhubaneswar, Orissa. The study revealed that the vermicompost prepared from biomass and byproducts of tuber crops had fairly higher levels of nitrogen (1.12–2.23%), phosphorus (0.26–0.88%), and potassium (0.33–1.29%) compared to initial status. The vermicompost prepared from sweet potato dry leaves had the highest nitrogen (2.23% and 2.03%), phosphorus (0.88% and 0.69%), and potassium (1.29% and 0.84%) content during both the years of study. Cassava thippi (tuber residue) required 40–43 days for the complete conversion into vermicompost, whereas all other biomass and byproducts needed more time (43–65 days). The rate of increase of earthworm weight and population was higher in vermicompost made from cassava and sweet potato thippi. Microbial counts indicated that populations of bacteria and fungi were higher in season I, whereas actinomycetes were higher in season II. The study indicated that all the biomass and byproducts of tuber crops can be effectively converted into high-value vermicompost.