Article

Impacts of earthworms on soil nutrients and plant growth in soybean and maize agroecosystems

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The objective of this experiment was to determine the effects of earthworms on soil N pools and plant growth in soybean and maize agroecosystems. The species and number of individuals in earthworm communities were manipulated in plot-scale field enclosures (2.4 m × 1.2 m) by first reducing earthworm populations within enclosures with carbaryl pesticide, and then adding earthworm treatments to the enclosures. Soybean was grown in the enclosures in the first year and stover maize in the second year.The success of earthworm manipulations in field enclosures was affected by climate conditions and available food resources. The endogeic earthworm species Aporrectodea caliginosa was dominant in all enclosures, while introduced anecic Lumbricus terrestris earthworms had poor survival. In the first season, when climate conditions were favourable for earthworm survival and growth, there was a significant (P < 0.05) linear increase in soil mineral-N and microbial biomass N concentrations in the 0–15 cm depth of enclosures with more earthworms. Similarly, soybean grain and grain-N yield was significantly (P < 0.05) greater in enclosures with the largest earthworm populations than the control which had no earthworms added. In the second season, when climate conditions were less favourable, there was no effect of earthworms on soil N pools or maize plants, probably due to poor survival of introduced earthworms.

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... Plant responses to earthworms are dependent on biological mechanisms that include competition among earthworms and plants for water and nutrients; increased microbial biomass and microbial activity; parasitic damage reduction; and increased nutrient absorption by the plant (GROENIGEN et al., 2014;LEMTIRI et al., 2014). Fiuza et al. (2012) found a beneficial effect of earthworms (Chibui bari) in maize and soil structure alteration, although soil microbial respiration did not change. By contrast, Lipiec et al. (2016) found earthworms had a significant influence on soil microbial functional diversity, making the soil less vulnerable to degradation and thus increasing the stability of ecologically relevant processes. ...
... In addition, aerial dry matter was more positively affected than root dry matter, and thus the aerial/root ratio increased. The positive influence of earthworms on common bean growth that we observed (Figure 3) corroborates other studies that have evaluated the interaction between earthworms and leguminous plants (KREUZER et al., 2004;ERIKSEN-HAMEL;WHALEN, 2007). In addition, similar effects have been observed in other species, such as ryegrass (Lolium perene L.), barley (Hordeum vulgare L.), corn (Zea mays L.), rice (Oryza sativa L.), and papaya (Carica papaya L.) (GROENIGEN et al., 2014;XIANG et al., 2016). ...
... In addition, aerial dry matter was more positively affected than root dry matter, and thus the aerial/root ratio increased. The positive influence of earthworms on common bean growth that we observed (Figure 3) corroborates other studies that have evaluated the interaction between earthworms and leguminous plants (KREUZER et al., 2004;ERIKSEN-HAMEL;WHALEN, 2007). In addition, similar effects have been observed in other species, such as ryegrass (Lolium perene L.), barley (Hordeum vulgare L.), corn (Zea mays L.), rice (Oryza sativa L.), and papaya (Carica papaya L.) (GROENIGEN et al., 2014;XIANG et al., 2016). ...
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Few studies have evaluated the effect of earthworms on plants and biological soil attributes, especially among legumes. The objective of this study was to evaluate the influence of earthworms (Amynthas spp.) on growth in the common bean (Phaseolus vulgaris L.) and on soil biological attributes. The experiment was conducted in a greenhouse using a completely randomized design with five treatments and eight repetitions. The treatments consisted of inoculation with five different quantities of earthworms of the genus Amynthas (0, 2, 4, 6, and 8 worms per pot). Each experimental unit consisted of a plastic pot containing 4 kg of soil and two common bean plants. The experiment was harvested 38 days after seedling emergence. Dry matter and plant height, soil respiration, microbial respiration, microbial biomass, and metabolic quotient were determined. Earthworm recovery in our study was high in number and mass, with all values above 91.6% and 89.1%, respectively. In addition, earthworm fresh biomass decreased only in the treatment that included eight earthworms per pot. The presence of earthworms increased the plant growth and improved soil biological properties, suggesting that agricultural practices that favor the presence of these organisms can be used to increase the production of common bean, and the increased soil CO2 emission caused by the earthworms can be partially offset by the addition of common bean crop residues to the soil.
... A c increased grass-N uptake, but no increases in either grass biomass or soil NH 4 + -N concentration were observed. Effects of earthworms on N mineralization Cortez et al., 2000;de Goede et al., 2003;van Vliet et al., 2007;Eriksen-Hamel & Whalen, 2008) as well as on plant growth Boyer et al., 1999;Eriksen-Hamel & Whalen, 2007) have been found before, but none of these studies assessed specific effects of earthworm functional groups or the effects of L r in particular. Only Postma-Blaauw et al. (2006) observed enhanced N mineralization when L r was present and, hence, a specific L r -effect on plant-N availability. ...
... Only Postma-Blaauw et al. (2006) observed enhanced N mineralization when L r was present and, hence, a specific L r -effect on plant-N availability. The effect of A c on plant-N availability that we found is in accordance with increased plant growth (Eriksen-Hamel & Whalen, 2007) and increased N mineralization from soil organic matter in the presence of A c (Postma-Blaauw et al., 2006). The large mortality rate of L r might have increased the amount of available N in the soil to some extent. ...
... This effect has also been demonstrated in several field studies Boyer et al., 1999). Even without the application of N fertilizer, the presence of earthworms has been reported to increase crop yield and crop-N uptake in grasslands (Eriksen-Hamel & Whalen, 2007). ...
Article
Earthworms are known to be important regulators of major soil processes and functions such as structure, organic matter (OM) decomposition, nutrient cycling, microbial composition and activity, and plant production. For instance, they have been reported to increase plant nitrogen (N) availability through increasing mineralization of organic matter. Recent studies have indicated that earthworms can also lead to elevated emissions of the potent greenhouse gas nitrous oxide (N2O) during crop residue decomposition. It is unclear to what extend these two effects interplay in fertilized grasslands, where earthworm densities are typically highest and N and C inputs are high and continuous. The objectives of this study were therefore to (i) quantify earthworm-induced N uptake and N2O emissions in fertilized grasslands, and (ii) to link these effects to earthworm functional groups. In a factorial lysimeter experiment, we introduced combinations of earthworm species in soil columns with growing grass on a loamy soil during a 73 day incubation period. Main effects as well as all 2- and 3-way interactions were tested for individuals that represented the three ecological earthworm strategies: Lumbricus rubellus [R] (epigeic), Apporectodea longa [L] (anecic), and Apporectodea caliginosa [C] (endogeic). Lysimeters were placed outside and the total amount of fertilizer applied during the incubation period amounted to 250 kg N ha-1. R increased grass biomass with 5.4 % (p=0.032) and grass N uptake from 171.5 to 187.6 kg N ha-1 (p
... L'impact des vers de terre sur la production végétale a été largement étudiés en mésocosmes (pots soumis aux conditions naturelles) et en microcosme (laboratoire) (Derouard et al.1997 ;Scheu et al., 1999 ;Wurst & Jones, 2003 ;Kreuzer et al., 2004 ;Blouin et al., 2006 ;Laossi et al., 2009;2010). Dans ces expériences où les variables environnementales (température, humidité du sol et la disponibilité des ressources) sont plus ou moins contrôlées et où la densité de vers de terre ajoutés ne reflète pas la réalité, leurs activités sont parfois exagérées (Eriksen-Hamel & Whalen, 2007). Souvent, lorsqu'ils sont réalisés en conditions naturelles, les organismes préexistants sont supprimés préalablement (Gilot et al. 1996 ;Pashanasi et al. 1996 ;Gilot, 1994;Ouédraogo et al., 2006 ;Eriksen-Hamel & Whalen, 2007). ...
... Dans ces expériences où les variables environnementales (température, humidité du sol et la disponibilité des ressources) sont plus ou moins contrôlées et où la densité de vers de terre ajoutés ne reflète pas la réalité, leurs activités sont parfois exagérées (Eriksen-Hamel & Whalen, 2007). Souvent, lorsqu'ils sont réalisés en conditions naturelles, les organismes préexistants sont supprimés préalablement (Gilot et al. 1996 ;Pashanasi et al. 1996 ;Gilot, 1994;Ouédraogo et al., 2006 ;Eriksen-Hamel & Whalen, 2007). Ceci ne traduit pas non plus la réalité car des interactions existent entres les différents organismes du sol et même entre espèces de vers de terre (compactants et décompactants). ...
... Toutefois, la réussite des travaux sur la manipulation des vers de terre en milieux paysans dépend des espèces utilisées (Derouard et al., 1997;Eriksen-Hamel & Whalen, 2007), du type de sol (Doube et al., 1997;Laossi et al., 2010), de l'espèce végétale (Pashanasi et al., 1996;Brown et al., 2004;Laossi et al., 2009), de sources de nourriture et surtout de la pluviométrie (Pashanasi et al., 1996;Eriksen-Hamel & Whalen, 2007). L'introduction de vers compactants peut entraîner non seulement une compaction du sol qui à long terme est néfaste pour les plantes, mais aussi pour les vers eux même (Derouard et al., 1997). ...
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The impact of two earthworms species with contrasting impact on soil functioning, Millsonia omodeoi (compacting) and Hyperiodrilus africanus (decompacting), on maize (Zea mays) growth and production were investigated in field conditions in the Centre-West region of Ivory Coast (Goulikao, Oumé). The treatments included: (i) maize + M. omodeoi (M+Mo), (ii) maize + H. africanus (M+Ha), (iii) maize + M. omodeoi+ H. africanus (M+Mo+Ha), (iv) maize + urea + super phosphate triple (M+U+SPP), and (v) the control (M). A total of 90 g of worms were inoculated per meter square at tree times: 25 g at 15 and 30 days after planting and 40 g, 45 days after planting. The perception of farmers about the effect of earthworms on soil fertility and crop yields was assessed through a survey of 95 farmers from the study site. Results maize production and water use efficiency was increased in inorganic fertilizer and worm-based treatments. Grain yields were enhanced by 21.5%, 21.2%, 19.4% and 13.9% in M+Mo, M+Mo+Ha, M+U+SPP and M+Ha treatments, respectively. The inoculation of earthworms along with the application of inorganic fertilizer have significantly enhanced cobs production and improve the water use efficiency of maize crops, which is likely due to the association of the two earthworm species. A survey undertaken among farmers in the study site showed that 49.3% farmers believed that earthworms positively influence soil fertility whereas 23% think the contrary. Regarding agricultural outputs, 57% of farmers think that earthworms increased crops yields contrarily to 31% of the farmers. As a result, 80% of farmers are willing to use earthworms for improving agricultural production. However, the economic cost of such technology is likely to be a bottleneck. Keywords: earthworms, functional groups, sustainable agriculture, maize crop
... Earthworms are present in soybean agroecosystems. Surveys conducted during the soybean growing season (May to October) report communities of 62 to 241 individuals m (2 in Indiana (Mackay and Kladviko 1985), Missouri (Jordan et al. 1997) andQuebec (Eriksen-Hamel andWhalen 2007). Earthworms may be exposed to insecticide present on the soil surface or washed into the soil profile by rainfall and irrigation. ...
... There were 62 to 434 earthworms m (2 in soybean fields on commercial farms in this study. This range is greater than the average earthworm population (62 to 241 individuals m (2 ) reported to live in soybean fields in temperate North America (Mackay and Kladviko 1985;Jordan et al. 1997;Eriksen-Hamel and Whalen 2007). ...
... As both earthworms (e.g. Edwards, 2004;Eriksen-Hamel and Whalen, 2007) and enchytraeids (Didden, 0929-1393/$ -see front matter © 2012 Elsevier B.V. All rights reserved. doi:10.1016/j.apsoil.2011.12.009 ...
... As both earthworms (e.g. Edwards, 2004;Eriksen-Hamel and Whalen, 2007) and enchytraeids (Didden, 0929-1393/$ -see front matter © 2012 Elsevier B.V. All rights reserved. doi:10.1016/j.apsoil.2011.12.009 ...
Article
Agricultural intensification generally results in the loss of soil organic matter, a decline in soil biodiversity, and the reduced ability of soils to retain nutrients. Intensified land-use can bring about legacy effects in soil ecosystem services that may last for hundreds of years after the cessation of agricultural practises. We studied, in a laboratory pot experiment, whether legacy effects due to intensive land/soil management (intensively managed wheat field) can be alleviated by restoring the disturbed soil with soil fauna typical of less managed soils (grassland soil). We also compared the effects of functional complexity of the soil fauna (microfauna, microfauna + mesofauna (enchytraeids), microfauna + macrofauna (earthworms, Aporrectodea caliginosa), all groups together) on the ability of wheat fields and grassland soils to retain nitrogen, carbon, the herbicide metribuzin and wheat biomass production, and whether these effects are a result of the land-use type. Our results showed that even after homogenising the soils in terms of soil macrostructure and faunal community composition, the legacy of land-use remained and affected the rates of soil processes. For example, wheat biomass production and the retention of nitrogen and carbon were higher but the retention of metribuzin was lower in the wheat field than in the grassland soil. The impacts of functional complexity of the fauna were mostly similar between the two soils: the retention of metribuzin and carbon (measured as dissolved organic carbon leaching) was impaired by the most complex faunal community and plant performance was improved by the presence of earthworms. However, impact of the fauna on soil organic matter dynamics was different in the two soils: in the grassland soil, meso- and macrofauna retarded whereas in the wheat field these fauna stimulated soil organic matter loss. We conclude that land-use history affects the level of ecosystem services provided by soils, and that restoring functionally complex faunal communities cannot alleviate the legacies of land-use in the short-term.
... Earthworms are known for their beneficial effects on soil structure, the provision of plant-available nutrients and their ability to reduce plant pathogens [3,[5][6][7][8]. Therefore, increasing earthworm abundance by provision of cover crops can lead to enhanced agricultural sustainability [3,4,[9][10][11]. ...
... However, a high biomass production of cover crops can also decrease soil moisture due to water uptake in the growing season and a low soil temperature in spring can retard cash crop emergence and be beneficial for soil-borne pathogens [13,16]. Nevertheless, for earthworm populations, an adequate soil moisture is paramount, therefore a trade-off between plant biomass production and earthworm abundance is possible, especially under dry conditions [10,13,[17][18][19]. ...
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Cover crops are an essential element of sustainable agriculture and can affect earthworm populations. In a field trial, we investigated the effects of four cover crop treatments: radish (Raphanus sativus var. longipinnatus B.; at high and low seed density), black oat (Avena strigosa Schreb.) and Sudan grass (Sorghum sudanese M.) on earthworms under two irrigation regimes. The two parallel field trials (irrigated and rainfed) demonstrated the significance of soil moisture for earthworm abundance with lower numbers under rainfed black oat and Sudan grass compared with moister bare fallow in autumn (P < 0.05). Soil moisture content changed from autumn to spring and was highest under Sudan grass in both irrigation regimes (P < 0.05). Earthworm numbers equalised and were then similar in all treatments, but under rainfed cover crop treatments, earthworm populations gained 62.3 g g⁻¹ in biomass from autumn to the following spring (P < 0.05). Laboratory experiments showed the importance of N content and more palatability of low C:N ratio radish for growth rate of juvenile Aporrectodea longa and cocoon production by Aporrectodea caliginosa. These two earthworm species showed a different preference in choice chamber experiments between roots and shoots. Radish was consumed first in three out of four experiments. Field and laboratory experiments highlighted the effects of cover crops on earthworm abundance, reproduction and development. Overall, our results showed that cover crops can support earthworm development, but under field conditions, soil moisture is more important. In the short-term, this can lead to a trade-off between plant biomass production and earthworm numbers.
... Earthworms have physical effects on soil structure (Angst et al., 2017;Brown et al., 2001;Scheu, 2003). Through their excavations, worms increase soil porosity and aeration (Datta, Singh, Singh, & Singh, 2016) and degrade organic wastes, which improves nutrient utilization by plants (Jansirani, Nivethitha, & Vijay, 2012;Pashanasi, Melendez, Szott, & Lavelle, 1992) and benefits their development (Eriksen-Hamel & Whalen, 2007). In addition, evidence indicates that worms benefit plant growth and productivity in arable or grassland soils (Ortiz-Ceballos & Fragoso, 2004). ...
... Las lombrices de tierra tienen efectos físicos en la estructura del suelo (Angst et al., 2017;Brown et al., 2001;Scheu, 2003). A través de sus excavaciones, las lombrices aumentan la porosidad y aireación (Datta, Singh, Singh, & Singh, 2016) y degradan los desechos orgánicos, lo cual mejora el aprovechamiento de nutrientes por las plantas (Jansirani, Nivethitha, & Vijay, 2012;Pashanasi, Melendez, Szott, & Lavelle, 1992) y beneficia su desarrollo (Eriksen-Hamel & Whalen, 2007). Además, las evidencias señalan que las lombrices favorecen positivamente el crecimiento y productividad vegetal en suelos arables o de pastizal (Ortiz-Ceballos & Fragoso, 2004). ...
Article
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Introduction: In nurseries, irrigation inside plastic bags contributes to soil compaction, affecting plant growth. Objective: To evaluate the effect of the earthworm Pontoscolex corethrurus Müller on the survival and growth of Abies religiosa (Kunth) Schltdl. & Cham. plants and on soil compaction in a nursery. Materials and methods: The plants were subjected to three treatments (adult earthworm, two juvenile earthworms and no earthworms) in plastic bags (250 cc, 400 gauge) with 25 replicates. One year later, the height, cover, number of primary and secondary branches and biomass production (root, stems and branches) of the plants were recorded and soil compaction evaluated. Results and discussion: The earthworm promoted an increase of 28 % in height and 44 % in root dry matter production (P < 0.05) without affecting survival, which was similar (86 ± 4.25 %; P > 0.05) in all three treatments. Compaction was significantly lower (48 %, P < 0.0001) in the earthworm treatments. Conclusion: P. corethrurus has the potential to improve the quality of plants grown in plastic bags in forest nurseries.
... Earthworms are present in soybean agroecosystems. Surveys conducted during the soybean growing season (May to October) report communities of 62 to 241 individuals m (2 in Indiana (Mackay and Kladviko 1985), Missouri (Jordan et al. 1997) andQuebec (Eriksen-Hamel andWhalen 2007). Earthworms may be exposed to insecticide present on the soil surface or washed into the soil profile by rainfall and irrigation. ...
... There were 62 to 434 earthworms m (2 in soybean fields on commercial farms in this study. This range is greater than the average earthworm population (62 to 241 individuals m (2 ) reported to live in soybean fields in temperate North America (Mackay and Kladviko 1985;Jordan et al. 1997;Eriksen-Hamel and Whalen 2007). ...
Article
Outbreaks of the exotic soybean aphid (Aphis glycines Matsumura) cause significant yield loss of soybean [Glycine max (L.) Merr.] grown in North America. This study assessed the toxicity of dimethoate and lambda cyhalothrin, recommended to control soybean aphid, to earthworms, a non-target organism present in soybean fields. Laboratory bioassays showed the lethal and sub-lethal concentrations of dimethoate and lambda cyhalothrin to adult Eisenia fetida (Savigny) and their offspring. The most sensitive toxicity endpoint was adult E. fetida growth rates, which had a half maximal effective concentration (EC 50) of 6.39 mg active ingredient (a.i.) kg (1 soil for dimethoate and 5.41 mg a.i. kg (1 soil for lambda cyhalothrin after 28 d exposure. The field bioassay was done on two commercial farms with naturally occurring earthworms (including Aporrectodea turgida, Allolobophora chlorotica, Aporrectodea rosea, Lumbricus terrestris and Eiseniella tetraedra). Soybean fields received insecticidal sprays during 2007 and 2008. Timely application of dimethoate (both farms) and lambda cyhalothrin (one farm) controlled the aphid outbreak in 2007 and increased soybean yield by 9 to 22% over the untreated control. These insecticide treatments had no effect on field earthworm populations, probably because application rates recommended to control soybean aphid were up to three orders of magnitude lower than the EC 50 determined in laboratory tests. In conclusion, recommended application levels of dimethoate and lambda cyhalothrin for soybean aphid control are not toxic to earthworms in soybean fields.
... In this study, the impact of herbicide application intensity on soil faunal biodiversity in sugar beet was assessed using 'earthworms' (Lumbricidae) as an indicator due to their significant impact on soil fertility and productivity (Buckerfield et al., 1997;Eriksen-Hamel and Whalen, 2007). The high variability of earthworm populations across regions and the relatively unambiguous ecological consequences of tillage practices are well-known and frequently published (reviewed by Chan, 2001;Holland, 2004). ...
Article
The application of herbicides in sugar beet (Beta vulgaris L.) is essential to prevent yield loss due to weed competition. According to German regulations, herbicides can be applied in mixtures with variable intensities. The ecological impact of the resulting strategies is still poorly understood. However, it was hypothesized that the influence of herbicide strategies on earthworm abundance, biomass, and diversity is minor compared to environment and tillage intensity in sugar beet. Therefore, additional specific factor variation seemed to be a prerequisite for getting valuable results. The herbicide strategies were applied in a ploughing system and a mulching system in 19 environments (site × year) in Germany in 2008 and 2009. Earthworm expulsions were carried out in spring and autumn with 2204 samples in total.The earthworm population was determined by environment and tillage system rather than by herbicide strategies. The environments displayed the largest variability in earthworm abundance, ranging from 12 to 195 individuals m−2, and a considerable variation in the occurrence of earthworm species. In spring, the deleterious impact of ploughing, with 80% lower mean earthworm abundance compared to the mulching system, was observed across all environments. During vegetation, the stronger increase in earthworm population in the ploughing system did not compensate for the initial differences. Regardless of intensity, the herbicide strategies were not accompanied by corresponding detrimental effects on earthworms between each other. In conclusion, the earthworm population was subjected to a multiplicity of influencing factors and the results markedly demonstrated for the first time the negligible effect of herbicide application intensity in sugar beet.
... Maize production, especially aboveground, grain and root biomass were significantly enhanced by earthworms. Previous studies investigating the effect of earthworm addition on crop production drew out similar results (Gilot-Villenave et al., 1996;Derouard et al., 1997;Blouin et al., 2006;Eriksen-Hamel & Whalen, 2007). In a maize-based pot study in Lamto, Derouard et al. (1997) found that the addition of earthworms (M. ...
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Objectives: To investigate (i) the role of earthworm communities in the integrated soil fertility management (ISFM) theory, and (ii) the mechanisms underlying the positive impact of earthworms on maize production. Methodology and results: A field mesocosm experiment was set up in a degraded agro-ecosystem in semi-deciduous forest areas in Central-West Côte d'Ivoire. Earthworm communities were composed of the association of decompacting (Hyperiodrilus africanus) and compacting (Millsonia omodeoi) native species known to be main species in natural populations and regulating soil structure in the area. In the presence of earthworms, there were significant increases in (i) maize growth 30 days after planting, and (ii) maize production (aboveground biomass, grains and root biomass). This significant impact was enhanced with inorganic fertilizers and/or earthworm inoculations. The increase in maize production in earthworm-based treatments is likely to be explained by increasing root biomass production, phosphorus and water use efficiency associated with earthworm engineering activities. Conclusions and potential application of findings: These findings highlight the crucial role played by earthworms in the ISFM theory through their engineering activities by enhancing the use of water and mineral fertilizers by maize roots. Farmers should encourage proliferation of earthworm populations in their fields as these fauna are important for sustainable agriculture production in agricultural systems.
... Some researchers found that vermicomposts enhance microbial populations and their functions in the soils, thus improving the plant growth and the development of plant resistance against plant pathogens, insects and nematodes ( Muscolo et al. 1996;Arancon et al. 2006). Other studies revealed positive effects on germination, seedling growth, flowering of ornamentals and crop yield even when vermicompost was added in little proportions only ( Arancon et al. 2004Arancon et al. , 2005Eriksen-Hamel and Whalen 2007;Gutierrez-Miceli et al. 2007). Hameeda et al. (2007) indicated that vermicompost may improve shoot length, leaf area and plant biomass of sorghum, whereas Atiyeh et al. (2000) showed that vermicompost supported the growth of marigold and tomato seedlings in glasshouse conditions. ...
Article
The melon aphid, Aphis gossypii Glover (Hem., Aphididae), is one of the most important pests of cucumber throughout the world. This aphid has a short generation time and high fecundity that result in an enormous reproductive potential, especially in cucumber‐growing greenhouses. Vermicomposts, which are produced by exploiting interactions between earthworms and microorganisms, may enhance plant growth and plant resistance against some pests and disease. In this study, the effects of vermicompost and cucumber cultivar (Cucumis sativus L.) on infestation levels with A. gossypii were evaluated. We conducted a factorial experiment with two cucumber cultivars (Royal and Storm) and five concentrations of vermicompost in the soil, including 0% (control), 10%, 20%, 30% and 50%, employing a randomized complete block design with four replicates. The experiment was conducted in a growth chamber at 25 ± 2°C, 65 ± 10% RH and a photoperiod of 14 L: 10 D h. The number of aphids was counted 3, 5, 7, 9, 12, 15, 18 and 21 days after infestation of cucumber seedlings by aphids. We found that in all vermicompost‐amended treatments, aphid numbers were lower than when plants were grown in soil without any vermicompost. The highest and lowest aphid counts occurred in the control treatment on cucumbers of the Royal cultivar and in the 30% and 50% vermicompost treatments on the storm cultivar, respectively. Overall, our study showed that the application of vermicompost has a high potential for reducing A. gossypii populations in cucumber cultures.
... In another experiment, the N flux through earthworms was equivalent to 16-30% of crop N uptake during 1994-1995 and 11-18% of crop N uptake during 1995-1996, with the difference attributed to unfavourable climatic conditions during the latter half of 1995 (Whalen & Parmelee, 2000). In a study in which carbaryl pesticide was used to remove earthworms prior to re-inoculation of the soil with Aporrectodea caliginosa and Lumbricus terrestris, soil mineral N was positively correlated with earthworm density, and N-microbial biomass and N-concentration in total grain-N per soybean plant also increased (Eriksen-Hamel & Whalen, 2007). ...
... increased. Thus, there was a concomitant increase in both inorganic N and the potentially available organic N pool due to the introduction of earthworms (Eriksen-Hamel and Whalen, 2007). Our result was also consistent with previous studies that earthworms facilitated the formation of soil water-stable aggregate formation. ...
... Earthworms are known to improve soil physical, chemical and biological components (Eriksen-Hamel and Whalen, 2007;Fragoso et al., 1997;Jégou et al., 2000;Lavelle, 1997). Moreover, they are sensitive to crop management, easily collected by both specialists and farmers, and thus can be used to evaluate different environmental pressures (Blouin et al., 2013;De Lima and Brussaard, 2010;Daugbjerg et al., 1988;Jamar et al., 2010). ...
... Celle-ci favorise à son tour la minéralisation de la matière organique et la libération de nutriments. Le processus est donc amplifié, ce qui explique l'importance du rôle des vers de terre en tant que régulateurs des cycles biogéochimiques dans les sols cultivés (Tiunov et Scheu, 1999 ;Eriksen-Hamel et Whalen, 2007a). ...
Article
Earthworms, which represent a major component of soil macrofauna, are often presented as biodiversity and soil quality indicators. Moreover, they are deemed to be ecosystem engineers since they directly or indirectly impact the availability of resources to other species as plants and microorganisms. Earthworms play a central role in the ecological functioning of agroecosystems thanks to their contribution to processes influencing physical, chemical and biological soil components. This work is aimed at understanding and modelling earthworm population dynamics in cultivated fields and to study the impact of cropping systems on earthworm communities. Our model, WORMDYN, is a stochastic stage-based Lefkovitch matrix model which accounts for vertical migrations and predicts Lumbricus terrestris dynamics in ploughed and superficially tilled plots (Grignon, France). In the model, the earthworm population is divided into four developmental stages (cocoons, juveniles, sub-adults, and adults) and life cycle parameters depend on soil temperature and water content which are the main factors influencing L. terrestris short-term dynamics. The model parameters were estimated from the available literature. This study of L. terrestris population dynamics entailed many samplings in cultivated fields. However, various methods are classically used for earthworm samplings. We thus wanted to determine the most suitable earthworm sampling method, combining efficiency and manipulator safety. The first part of this work thus presents the comparison of three chemical expellants for earthworm sampling. Then, WORMDYN structure is presented, as well as the comparison between model outputs and experimental data. A sensitivity analysis was carried out to identify the parameters which should be estimated with a higher precision in order to improve the predictive capabilities of the model. Finally, to assess the impact of cropping systems on earthworm communities, data were collected in a long-term trial including three cropping systems: a conventional system, a "Direct seeding living Mulch-based Cropping system" and an organic system without fertilisation. Results were used to study WORMDYN behaviour in these situations and to get information to improve model performance.
... Earthworms are known to improve soil physical, chemical and biological components (Eriksen-Hamel and Whalen, 2007;Fragoso et al., 1997;Jégou et al., 2000;Lavelle, 1997). Moreover, they are sensitive to crop management, easily collected by both specialists and farmers, and thus can be used to evaluate different environmental pressures (Blouin et al., 2013;De Lima and Brussaard, 2010;Daugbjerg et al., 1988;Jamar et al., 2010). ...
... Bohlen et al., 1995) and in a study by Shuster et al. (2003) addition of L. terrestris individuals within enclosures, with different tillage treatments did not result in establishment of L. terrestris. Eriksen-Hamel and Whalen (2007) also found L. terrestris number to be similar in manipulated (earthworm addition/earthworm reduction) and control enclosures over 2 years and suggested that this was a result of high mortality of introduced individuals in addition treatments and persistence of L. terrestris individuals and cocoons in the reduction treatments. ...
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A field experiment in managed woodland was set up to examine the effects of manipulated population density and resource availability on spatial distribution and dispersal of the anecic earthworm Lumbricus terrestris. Experiments over 2 years, made use of 1 m2 field enclosures with associated trapping units to assess emigration rates at control and enhanced L. terrestris densities and different levels of leaf litter availability. Densities were manipulated twice; at the outset and again after 1 year when visually tagged animals obtained from 2 origins were introduced. Population density had a significant effect on dispersal (p
... Earthworms are known to improve soil physical, chemical and biological components (Eriksen-Hamel and Whalen, 2007;Fragoso et al., 1997;Jégou et al., 2000;Lavelle, 1997). Moreover, they are sensitive to crop management, easily collected by both specialists and farmers, and thus can be used to evaluate different environmental pressures (Blouin et al., 2013;De Lima and Brussaard, 2010;Daugbjerg et al., 1988;Jamar et al., 2010). ...
... They amplified around 10% additional P accumulation to above-ground plant tissues. Previous studies (Derouard et al., 1997;Blouin et al., 2006;Eriksen-Hamel and Whalen, 2007) on influence of earthworms in various crops also reported similar findings. The utilization of P by AM was not significantly different from the utilization by non-AM plants. ...
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Phosphate rock (PR) is essentially insoluble in water. Dissolution of PR under acidic soil conditions is a necessary prerequisite for uptake of phosphorus (P) by plant. Improvement in P dissolution could be achieved through the interaction of micro-and macro-organisms in soil. A greenhouse pot experiment was conducted with epigeic earthworms (W) (Pontoscolex corethrurus M.), arbuscular mycorrhizae (AM) fungi (Glomus mosseae Tul), and gafsa phosphate rock (GPR) to evaluate their effects on dry matter (DM), root colonization, and nutrient accumulation of setaria grass (Setaria splendida) and availability of P in the soil. Earthworms significantly increased DM yield (23.3 g pot-1) and P accumulation (16 mg P pot-1) of setaria grass. The AM colonization on inoculated plants was high (81%) compared to earthworms. Accumulation of P, N, K, Ca 2+ and Mg 2+ in grass were significantly higher in soils contained earthworms, compared to other treatments. Presence of worm (W), AM, and GPR significantly increased phosphorus utilization efficiency (PUE) of setaria grass. The residual P was lower in the soils treated with worm or AM compared to non-treated (control) soil which might be due to higher P uptake by setaria grass. However, plant's available P increased under AM or W treatment. There was a significant interaction effect between AM, W and GPR on P accumulation of setaria grass indicating, efficiency of grass in taking up phosphorous. Thus, it could be concluded that presence of W, AM and GPR have efficiency to increase the amount of plant available P in soil.
... The second reason might be that the population of earthworms was not enough to have a significant effect on plant growth. The contributions of earthworms to plant growth in some agro-ecosystems are significant when their populations are sufficiently high (> 300 individuals m -2 ) and when favorable weather conditions exist (Eriksen-Hamel and Whalen, 2007). They assumed that the 0-15 cm depth soil with a high earthworm population (300 individuals m -2 ) could contain 14 kg N ha -1 more compared to soils with low earthworm population (30 individuals m -2 ). ...
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Increasing phosphorus (P) availability in tropical P deficient soils is a challenging task. Vermicomposting of organic wastes in the presence of phosphate rock facilitates the release of P and this has the potential to address crop P needs. A study was conducted to assess and compare the effects of application of gafsa phosphate rock (GPR) alone and GPR in combination with empty oil palm fruit bunches, earthworms (Pontoscolex corethrurus), arbuscular mycorrhiza fungi (Glomus mosseae), and P-enriched vermicompost, in fulfilling the P requirements of the setaria (Setaria splendida L.,) grass. Application of mixed organic fertilizer combined with GPR was effective in increasing dry matter yield of grass, with 19% higher dry matter production as compared to the use of GPR alone. Among the organic fertilizers, application of P-enriched vermicompost was the best to support the grass growth. Nitrogen, P, Ca, and Mg uptake of the grass treated with P-enriched vermicompost was higher. Nitrogen and P utilization efficiency of the setaria grass treated with P-enriched vermicompost was also high. Residual P in soil treated with GPR was higher as compared to that treated with P-enriched vermicompost. However, plant available P was higher than that for the other GPR application techniques. The different types of earthworms had no effect on the quantum of nutrient uptake and the dry matter yield of the setaria grass. Application of a mixture of GPR and empty oil palm fruit bunch to the soil increased the dry matter of setaria compared to the use of inorganic fertilizer alone. We conclude that soil treated with P-enriched vermicompost was an efficient treatment for increasing availability of P (24.28 mg kg-1), N, P, Ca and Mg uptake (53.76, 41.83, 13.58 and 15.16 mg pot-1, respectively); which ultimately enhanced root volume (163 cm3) and dry matter yield (5.75 to 6.46 g pot-1).
... In another experiment, the N flux through earthworms was equivalent to 16-30% of crop N uptake during 1994-1995 and 11-18% of crop N uptake during 1995-1996, with the difference attributed to unfavourable climatic conditions during the latter half of 1995 (Whalen & Parmelee, 2000). In a study in which carbaryl pesticide was used to remove earthworms prior to re-inoculation of the soil with Aporrectodea caliginosa and Lumbricus terrestris, soil mineral N was positively correlated with earthworm density, and N-microbial biomass and N-concentration in total grain-N per soybean plant also increased (Eriksen-Hamel & Whalen, 2007). ...
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Biodiversity is responsible for the provision of many ecosystem services; human well-being is based on these services, and consequently on biodiversity. In soil, earthworms represent the largest component of the animal biomass and are commonly termed ‘ecosystem engineers’. This review considers the contribution of earthworms to ecosystem services through pedogenesis, development of soil structure, water regulation, nutrient cycling, primary production, climate regulation, pollution remediation and cultural services. Although there has been much research into the role of earthworms in soil ecology, this review demonstrates substantial gaps in our knowledge related in particular to difficulties in identifying the effects of species, land use and climate. The review aims to assist people involved in all aspects of land management, including conservation, agriculture, mining or other industries, to obtain a broad knowledge of earthworms and ecosystem services.
... Earthworms accelerate rates of organic matter breakdown and stabilisation, increase soluble nutrient content and shift the same into deeper soil layers; thus they contribute to nutrient turnover. [119,143,144,145]. ...
... In another experiment, the N flux through earthworms was equivalent to 16-30% of crop N uptake during 1994-1995 and 11-18% of crop N uptake during 1995-1996, with the difference attributed to unfavourable climatic conditions during the latter half of 1995 (Whalen & Parmelee, 2000). In a study in which carbaryl pesticide was used to remove earthworms prior to re-inoculation of the soil with Aporrectodea caliginosa and Lumbricus terrestris, soil mineral N was positively correlated with earthworm density, and N-microbial biomass and N-concentration in total grain-N per soybean plant also increased (Eriksen-Hamel & Whalen, 2007). ...
Article
Full-text available
Biodiversity is responsible for the provision of many ecosystem services; human well-being is based on these services, and consequently on biodiversity. In soil, earthworms represent the largest component of the animal biomass and are commonly termed ‘ecosystem engineers’. This review considers the contribution of earthworms to ecosystem services through pedogenesis, development of soil structure, water regulation, nutrient cycling, primary production, climate regulation, pollution remediation and cultural services. Although there has been much research into the role of earthworms in soil ecology, this review demonstrates substantial gaps in our knowledge related in particular to difficulties in identifying the effects of species, land use and climate. The review aims to assist people involved in all aspects of land management, including conservation, agriculture, mining or other industries, to obtain a broad knowledge of earthworms and ecosystem services.
... These are standard species in ecotoxicological testing and have shown to respond sensitively to char materials (e.g. Park et al., 2011;Busch et al., 2012). They are also relevant due to the interactions between earthworm activity and plant growth in natural systems, being attributed to the earthworms' role in nutrient cycling (Brown et al., 2004;Eriksen-Hamel and Whalen, 2007;. ...
Article
Small-scale Terrestrial Ecosystem Models (STEMs) are valuable tools in soil ecotoxicological approaches. We assessed the effects of topsoil incorporation (0–15 cm) of a biochar-based organic N-fertilizer on the weight and vertical distribution of Eisenia andrei (epigeic earthworm) and on germination and growth of Brassica rapa (turnip) in STEMs. Single-species earthworm avoidance behaviour (ISO 17512-1:2005) and plant germination (based on ISO 11269-2:2012) tests were also performed for contextualization.
... Consequently, earthworm species that are currently found in this region were introduced by European settlers over the course of recent centuries (Gates 1982). Today, most agricultural fields in the province of Québec are colonized by exotic earthworm species, where their effects on nutrient cycling (Eriksen-Hamel and Whalen 2007) and soil structure (Blouin et al. 2013) have been amply described. In recent decades, earthworms have also been reported in forest ecosystems located north and east of Quebec's agricultural belt (Moore et al. 2009;Drouin et al. 2016), as well as in forest ecosystems of neighbouring regions of Canada and the U.S. (McLean and Parkinson 1997;Burtelow et al. 1998;Hale et al. 2006). ...
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It is generally accepted that human activities are responsible for the dispersal of exotic earthworms in northeastern North America. We know little, however, about the relative effects of concurrent human activities on the structure of these earthworm communities in protected forest areas, nor on their impacts on soil biological activities. Our first objective was to infer the relative importance of recreational fishing and road traffic on the structure of Lumbricidae communities in Mont-Tremblant National Park, the oldest conservation area in the province of Quebec, Canada. Our second objective was to test the relationship between earthworm species abundances and soil properties related to microbial and nitrogen dynamics. We sampled earthworm communities around 61 lakes, which included 23 heavily-fished lakes and 20 non-fished lakes located near roads, as well as 18 non-fished lakes located in remote areas of the park. Our results revealed that fishing and proximity to roads both have a positive effect on the abundance of earthworms, as does the soil pH. Fishing activities had a greater effect than road proximity on the abundance and diversity of earthworm communities, notably on the abundance of the anecic species Lumbricus terrestris. To assess at a finer scale the effects of earthworm community structure on soil microbial and nitrogen dynamics, we collected and analyzed soils from 47 sampling points around two lakes with high earthworm densities. Exploratory redundancy analysis found a negative correlation between epigeic and anecic earthworm species, with the former correlating positively to microbial biomass and the latter correlating positively to nitrification and denitrification. Confirmatory path analysis established a positive indirect effect of Lumbricus terrestris, the preferred fishing bait, on potential soil nitrous oxide emissions. We conclude that the human-mediated dispersion of earthworms in the most pristine ecosystems of Quebec affects ecosystem functioning and thus requires a review of current policies regarding the use of live-bait by fishermen.
... An excessive reduction in soil biodiversity, especially the loss of species with key functions, may result in severe effects including the long term degradation of soil and the loss of agricultural productive capacity (Nuria et al, 2008). Presence of soil organisms is beneficial to agro ecosystems (Edwards and Fletcher, 1988;Lavelle, 1988;Lavelle et al, 1997;Edwards, 1998;Eriksen and Whalen, 2007). ...
Article
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—Sampling was done in wet and intermediate zones represented by the Walpita and Makandura research centers,respectively. Eleven land use systems were considered for the study; coconut mono culture (CM), bare land (BL) and coconut multiple cropping. Under coconut multiple cropping, nine different intercrops were selected separately for each zones. The treatments were arranged in a randomized complete block design (RCBD) with three replicates (n = 3). The experiment was conducted under mature baring coconut (>20 years) plantation. Soil Macrofauna was sampled using one transect with three replicates at each land use type using quadrate size (30×30cm) from 0-30 cm depth and visible organisms were handpicked and preserved in 75% alcohol. Dilute plate technique and Spread plate technique was used to determine the soil micro organisms’ density. Those techniques were used to cultivate the fungi and bacteria under 10−2 and 10−5 dilution level respectively. Research identified 12 classes (Crusteacea, Oligochaeta, Hirudinea, Gastropoda, Acarina, Araneida, Scopionida, Chilapoda, Diplopoda, Amphibia, Reptelia) and 14 orders (Hemiptera, Diptera, Coleoptera, Thysanura, Hymenoptera, Lepidotera, Orthoptera, Blattaria, Mantodea, Phasmida, Dermaptera, Isoptera, Siphonaptera, Thysanoptera) of soil organisms. Class insecta shows the high diversity with 14 orders. Colony forming unit (CFU) value of bacteria was higher than that of the fungi value. Findings of intermediate and wet zones’ studies suggested that coconut multiple cropping systems may have high diversity, abundance and functional role of soil organisms. Both zones studies suggested that coconut multiple cropping systems may increase soil moisture factor, respiration rate, biomass carbon content, organic carbon percentage, total nitrogen content, organic matter content and C:N ratio in 0-30 cm depth other than the coconut monoculture systems. Overall data of two different zones indicated a significant positive correlation of soil organism diversity, abundance and their functional role with cropping systems. Those data can be used as a reliable basic bio indicator for payments for ecosystem services (PES). It supports to valorize the economic value of the ecological services returned by soil organisms.
... Earthworms (Annelida: Oligochaeta) are a large and common component of soil biodiversity and, as "ecosystem engineers," are one of the most important actors in the soil . In agricultural soils, earthworms are generally beneficial for plant growth and crop yield (Brown et al., 2004;Eriksen-Hamel and Whalen, 2007). The effects of different species of earthworms are related to their ecological functional guild, a classification scheme based on a species' diet and its location in, and movement through, the soil layers (Bouché, 1977;Brown et al., 2004;Hale et al., 2005). ...
Article
Earthworms, which play a key role in biogeochemical processes in soil ecosystems, could be negatively affected by the cultivation of transgenic Bt crops. Studies to date have found few effects of Bt maize on earthworm species. If adverse effects occur, they are likely to be chronic or sub-lethal and expressed over large spatial and temporal scales. Our objective in the present study was to investigate potential effects on earthworm populations in soil cultivated with Bt maize in a large multiple-year field study. We surveyed the earthworm populations in 0.16-ha experimental field plots of two varieties of Cry1Ab Bt maize, one variety of Cry3Bb1 Bt maize, and three non-transgenic control varieties cultivated for four years. Four earthworm species were found in our sample: Aporrectodea caliginosa, Aporrectodea trapezoides, Aporrectodea tuberculata (collectively, the A. caliginosa species complex), and Lumbricus terrestris. We found no significant differences in the biomass of juveniles and adults for all four species between Bt and non-Bt maize varieties. From this and previous studies, we conclude that the effects of Cry1Ab and Cry3Bb1 Bt maize on the A. caliginosa species complex and L. terrestris are small. Nonetheless, general conclusions about the effects of Bt maize on earthworm populations are not warranted due to the small number of species tested. In future laboratory studies, earthworm species should be selected according to their association with a Bt crop and the impact of that species to valued soil ecosystem processes.
... This experiment confirms, on the one hand, the beneficial effect of fertilization on plant growth, and on the other hand, decreased the damage of whiteflies on normal growth of tomato plants when treated with PWV. Although, the role of vermicompost in plant growth and development has been well documented in a large volume of studies (Arancon et al. 2004(Arancon et al. , 2005Eriksen-Hamel and Whalen 2007;Gutierrez-Miceli et al. 2007;Chanda et al. 2011;Razmjou et al. 2011), relatively little attention has been directly paid to the beneficial effects of vermicomposts on growth parameters of plants when experienced an arthropod attack. ...
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The effect of four vermicomposts, obtained from different organic sources (pistachio waste [PWV], date waste [DWV], cattle manure waste [CMV], and food waste [FWV]), as well as two chemical fertilizers (complete fertilizer [CF] and NPK fertilizer [NPK]) on some life history traits of the sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) was investigated in a series of choice and not choice experiments. In a choice experiment, adult whiteflies exhibited significantly lower preference for settling and oviposition on plants treated with vermicomposts than those in control, CF, and NPK groups (P < 0.01), with better results were observed in PWV group. In no choice experiment, adult whiteflies laid significantly fewer eggs in PWV group in comparison with control, CF, and NPK groups (P < 0.01); other treatments had intermediary values. Fertilization had a significant effect on the preadult development time of sweetpotato whitefly, with the longest development times were recorded for plants treated with PWV (24.65 d) and FWV (22.04 d), respectively. The preadult mortality of sweetpotato whitefly increased significantly following fertilization, with the greatest mortal effects were observed in PWV (54.11%) and DWV (44.68%) groups, respectively. Plants fertilized with PWV had significantly higher phenolic content (10 mg/ml) than control (BAGA; 6.08 mg/ml), while those in CMV group exhibited intermediary value (7.28 mg/ml). Altogether, results of this study reveal both antixenosis (nonpreference) and antibiosis (decreased survival and prolonged development time) resistance of tomato plants mediated by vermicomposts. Particularly, plants treated with PWV obtained the best results in terms of both growth and resistance to sweetpotato whitefly.
... In April 2004, field enclosures were installed at the study site to permit manipulation of earthworm populations and functional groups (Eriksen-Hamel and Whalen, 2007). These rectangular enclosures measured 2.44 m long  1.2 m wide (2.9 m 2 ), with the longest side along the east-west axis. ...
Article
Earthworm activity is expected to have a beneficial effect on soil structure and plant growth in agroecosystems, but active populations are temporally dynamic and spatially heterogeneous under field conditions. The objective of this research was to evaluate the temporal and spatial variation in surface casting by earthworms at the row-interrow scale in a temperate soybean agroecosystem. Earthworm populations were manipulated in 2.9m2 field enclosures by applying carbaryl pesticide to reduce the naturally occurring earthworm population before juveniles and adults of Aporrectodea caliginosa (Sav.) and Lumbricus terrestris L. were added. Surface casting was measured weekly during a 14-week period. There was very little surface casting during the first 6 weeks of the study, possibly due to insufficient food resources and shade at the soil surface. We collected nearly 3400 casts from weeks 7 to 14, and surface casting rates during this period ranged from 0.95 to 2.51gdryweightm−2day−1. More casts were deposited within 30cm of the soybean row than at distances up to 50cm from the row, indicating that the planted row was a zone with greater earthworm activity than the inter-row. Better understanding of the timing and small-scale variation in earthworm activities will aid our understanding of how earthworms contribute to plant growth.
... Earthworms casts are characterized by higher pH, C, Ca 2+ , Mg 2+ , and K + contents than surrounding soil aggregates and incorporate nutrients available for plants [7,8]. The N mineral availability increases with earthworm abundance [9,10]. Earthworms, through their interaction with microorganisms, are essential factors influencing soil organic carbon and its dynamics [10,11]. ...
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Earthworm species composition, the density of individuals, and their biomass were investigated in spring barley and faba bean fields in a long-term (52-year) experiment conducted at the Production and Experimental Station in Bałcyny, in north-eastern Poland (53°40′ N; 19°50′ E). Additionally, post-harvest residues biomass, soil organic matter (SOM), and soil pH were recorded. The above traits were investigated using two experimental factors: I. cropping system—continuous cropping (CC) vs. crop rotation (CR) and II. pesticide plant protection: herbicide + fungicide (HF+) vs. no plant protection (HF−). A total of three species of Lumbricidae were found: Aporrectodea caliginosa (Sav.) in both crops, Aporrectodea rosea (Sav.) in spring barley, and Lumbricus terrestris (L.) in faba bean. The density and biomass of earthworms were unaffected by experimental treatments in spring barley fields, whereas in faba bean CC increased and HF+ decreased earthworm density and biomass in comparison with CR and HF− respectively. Total post-harvest residues in faba bean fields were higher under CC in relation to CR and under HF+ compared with HF− treatment in both crops. Compared to CR, CC increased soil pH in spring barley fields and decreased in faba bean fields. Experimental factors did not affect SOM. Earthworm density and biomass were positively correlated with SOM content.
... It has been indicated by earlier _________________________________________________________________________________________________________________________ Page30 reports that pesticide application pose threat to their lives as they are exposed to soil contaminated by pesticides (4). They constitute up to 92% of the invertebrate biomass in the soil and become easily susceptible to pesticides applied in agricultural fields (5). Susceptibility and sensitivity to the soil pollutants in earthworms is much more as compared to other soil inhabitants (6). ...
Article
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Environmental conservation has been a burning topic for the past few decades and conservation and health monitoring of soil and soil biota is a domain that needs to be dealt with which is directly related to agriculture, food and human health. Due to indiscriminate of chemical fertilizers the soil health and the ecology of soil organisms has been drastically deteriorated. Beneficial non-target organisms are harmed as a result of pesticide application, earthworms being the most common and abundant amongst them. Cypermethrin is one of the commonly used synthetic pyrethroid pesticides in agricultural field. Perionyx excavatus is an indigenous species of epigeic earthworm found in abundance in the uncultivated grasslands, around Midnapore district of West Bengal, that are free from direct pesticide contamination and are collected from there. In this study, acute toxicity of selected earthworms was evaluated following the 96-hr LC50 test under laboratory conditions. Similarly, chronic toxicity of preclitellete and adult earthworms Perionyx excavatus was evaluated by exposing them to sublethal concentrations i.e. 25% of LC50 (T1) and 50% of LC50 (T2) of cypermethrin (Cypermethrin-T1-3.0 µg/kg soil, T2-6.0 µg/kg soil) for 28 days to detect their developmental changes and changes in cellular enzyme activities respectively, under laboratory conditions. Our results showed that cypermethrin could lead to significant reduction of biomass, reduced cocoon production and changes in acid and alkaline phosphatase activity. We found that in case of T2 sublethal dose of cypermethrin cocoon production was reduced to nil. In summary, we found that cypermethrin induced both developmental and enzymatic changes in Perionyx excavatus, contributing to a more comprehensive evaluation of the safety of the synthetic pyrethroid. These parameters can also be used as effective tools in detecting pesticide pollution in agro-ecosystems.
... It has been indicated by earlier _________________________________________________________________________________________________________________________ Page30 reports that pesticide application pose threat to their lives as they are exposed to soil contaminated by pesticides (4). They constitute up to 92% of the invertebrate biomass in the soil and become easily susceptible to pesticides applied in agricultural fields (5). Susceptibility and sensitivity to the soil pollutants in earthworms is much more as compared to other soil inhabitants (6). ...
Article
Full-text available
Environmental conservation has been a burning topic for the past few decades and conservation and health monitoring of soil and soil biota is a domain that needs to be dealt with which is directly related to agriculture, food and human health. Due to indiscriminate of chemical fertilizers the soil health and the ecology of soil organisms has been drastically deteriorated. Beneficial non-target organisms are harmed as a result of pesticide application, earthworms being the most common and abundant amongst them. Cypermethrin is one of the commonly used synthetic pyrethroid pesticides in agricultural field. Perionyx excavatus is an indigenous species of epigeic earthworm found in abundance in the uncultivated grasslands, around Midnapore district of West Bengal, that are free from direct pesticide contamination and are collected from there. In this study, acute toxicity of selected earthworms was evaluated following the 96-hr LC50 test under laboratory conditions. Similarly, chronic toxicity of preclitellete and adult earthworms Perionyx excavatus was evaluated by exposing them to sublethal concentrations i.e. 25% of LC50 (T1) and 50% of LC50 (T2) of cypermethrin (Cypermethrin-T1-3.0 µg/kg soil, T2-6.0 µg/kg soil) for 28 days to detect their developmental changes and changes in cellular enzyme activities respectively, under laboratory conditions. Our results showed that cypermethrin could lead to significant reduction of biomass, reduced cocoon production and changes in acid and alkaline phosphatase activity. We found that in case of T2 sublethal dose of cypermethrin cocoon production was reduced to nil. In summary, we found that cypermethrin induced both developmental and enzymatic changes in Perionyx excavatus, contributing to a more comprehensive evaluation of the safety of the synthetic pyrethroid. These parameters can also be used as effective tools in detecting pesticide pollution in agro-ecosystems.
... Earthworm casts often contain higher levels of available nutrients for plants (inorganic P, Ca, Mg, K, Na) as well as higher organic C and N contents than non-ingested soil (Hulugalle and Ezumah 1991;van Groenigen et al. 2019), which can be due to selective feeding on C-and N-rich soil fractions, finer soil particles (e.g. more clay) or decomposing plant material (Barois et al. 1999;van Groenigen et al. 2019). Moreover, casts are also zones of intense microbial activity (Scheu 1987;Devliegher and Verstraete 1997) that stimulate N and P mineralization, as well as CO 2 and N 2 O emissions (Eriksen-Hamel and Whalen 2007;Lubbers et al. 2011). ...
Article
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Greenhouse gas emissions (CO2, N2O, CH4) and chemical, physical and microbiological properties (pH, macro and micronutrients, texture, moisture, exchangeable NH4⁺, NO3⁻, total C and N, organic C, microbial biomass C and metabolic coefficient) were monitored in casts of a large, endogeic native Brazilian earthworm species Rhinodrilus alatus and from non-ingested control soil incubated for up to 32 days. Earthworm casts represented a significantly different chemical and microbiological environment, with higher soil moisture, pH, H + Al, exchangeable NH4, Cu, Fe and Mn contents, lower microbial biomass C and higher metabolic quotient (qCO2), but with few differences in CO2, N2O and CH4 emissions compared with non-ingested control soil. Nonetheless, fermenting, methanogenic and nitrate-reducing microbes encountered ideal conditions for sustained anaerobic activity in the clayey, dense and moist castings of R. alatus, maintaining emission of N2O and CH4 and confirming previous results observed using gut contents. The high exchangeable NH4 and H2O contents influenced the oxy-reduction processes, affected GHG emissions and N transformations and modified soil microbial biomass and activity. In addition, selective ingestion concentrates C and N contents in the casts and transformation processes affect the availability of important plant nutrients, topics that deserve further attention, considering the widespread collection of this species for use as fish-bait in Brazil.
... Our failure to manipulate earthworm populations at multiple field sites highlights the challenges of carrying out controlled field experiments involving artificially elevated earthworm populations. Previous field enclosure experiments also reported difficulties in manipulating earthworm populations in the field and reported low survival rates of introduced earthworms (Bohlen et al., 1995;Boyer et al., 1999;Eriksen-Hamel and Whalen, 2007;Speratti et al., 2007). For example, earthworms added to 2.9 m 2 field enclosures in a southern Quebec agroecosystem in June and recovered in October of the same year did not result in larger populations than the control enclosures (Speratti et al., 2007). ...
Article
Many laboratory and mesocosm studies have demonstrated that earthworms influence nitrogen (N) cycling reactions that produce nitrous oxide (N2O) in well-aerated soils, but whether earthworms can stimulate N2O fluxes in realistic field conditions remains to be determined. We conducted two field experiments in southern Quebec in perennial forage agroecosystems for 2 yr and agriculture riparian buffers for 1 yr to compare N2O fluxes from enclosures with ambient and artificially elevated earthworm populations. Despite a short-term (< 3 month) increase in mean N2O fluxes from the perennial forage enclosures with artificially elevated earthworm populations, this effect disappeared within 1 yr, with no significant difference (p > 0.05) in mean N2O flux from enclosures in either field experiment. The elevated earthworm populations declined and stabilized at the same level as the ambient earthworm populations within 1–2 yr after the field experiments began. The homeostatic regulation of earthworm populations under field conditions could be related to inter- and intra-specific competition and limits to the food supply and habitat preferred by earthworms. Mean N2O fluxes in the perennial forage fields were negatively correlated with soil moisture, but not related to earthworm populations. In the riparian buffers, the average N2O flux was negatively correlated with vegetation cover, and positively correlated with soil moisture and the size of the earthworm population at the end of the study. Our results suggest that the effects of earthworm addition on N2O emissions measured from laboratory studies can not necessarily be extrapolated to field settings. Earthworm field experiments that continue in the longer-term and in a variety of ecosystems should provide better understanding of the seasonal and environmental variability of earthworm activity and N2O balance under field conditions.
... T here is a growing interest in the use of earthworms in agriculture for their ability to improve soil physical properties (Dutt, 1948;Bouma et al., 1982;De Oliveira et al., 2012) and nutrient cycling (Eriksen-Hamel and Whalen, 2007); however, the distribution and survival of earthworms is controlled and greatly limited by the presence of water in the soil (Lee, 1985). Earthworms require water for respiration, to keep their bodies turgid, and for the mucus that coats their bodies and helps them move through the soil (Ramsay, 1949;Whalen et al., 2000). ...
Article
The distribution of earthworms is limited in many areas in the semiarid western United States by the availability of water and low soil organic matter; however, earthworms have been shown to adapt to periods of low soil moisture by making small chambers and entering estivation to protect themselves from declining soil moisture. The objective of this study was to investigate the effects of varying lengths of drought stress on the survival of earthworms in a low organic matter soil from eastern Colorado that was amended with biosolids to increase organic matter. The earthworms were exposed to constant water content or cycles of 1-, 2-, or 3-wk drought stress periods, which resulted in average soil water matric potentials of -0.061, -0.085, -0.13, and -0.19 MPa, respectively. Replicate pots were destructively sampled at 21, 42, and 63 d. At sampling, the earthworms were classified as either active, in estivation, or dead. Drought did not affect earthworm mass, but drought lasting 2 or 3 wk increased the number of A. caliginosa in estivation. Three weeks of drought resulted in a mortality rate of 14%, with all other drought treatments having negligible mortality rates. The average number of A. caliginosa in estivation decreased with time, from 1.71 at 21 and 42 d to 0.75 at 63 d. Based on these results, A. caliginosa has the potential to survive up to 3-wk drought periods and after introduction, can adapt to this Colorado soil with time, but field studies would need to confirm these results.
Article
A three-stage tower earthworm eco-filter was designed and constructed to remove carbon and nutrients simultaneously from domestic wastewater. The first and second stages provided good aerobic conditions for nitrification, while the third stage provided suitable conditions for denitrification in the presence of external carbon (glucose). The influence of temperature, hydraulic load (HL) and carbon to nitrogen (C/N) ratio of tertiary influent on the performance of tower earthworm eco-filter was investigated in this study. During stable operation period, this system performed well on various pollutants removal, with the average chemical oxygen demand (COD), total phosphorus (TP), nitrate nitrogen (NO(3)-N), nitrite nitrogen (NO(2)-N), ammonium nitrogen (NH(3)-N), and total nitrogen (TN) in tertiary effluent at 17.59, 0.12, 2.79, 0.044, 0.76 and 4.08 mg/L, respectively. All pollutants removal showed independence on temperature. It was found that the effluent concentrations of TN, NO(3)-N and COD were related to HL. With the increase of HL from 0.25 to 0.50 m/d, the average TN, NO(3)-N and COD in tertiary effluent increased from 4.67 to 7.40 mg/L, from 3.05 to 6.28 mg/L, and from 15.17 to 19.75 mg/L, respectively. The variation in C/N ratio of tertiary influent affected TN and NO(3)-N removal, and more than 95% of TN removal occurred at tertiary influent C/N ratio in the range of 4.76-7.41.
Article
A field experiment was conducted to investigate the effects and mechanisms of earthworm (Metaphire guillemi) activities on the winter oilseed rape (Brassica napus L. Zhongshuang 9) growth before winter. Present study included inoculated with (E) or without earthworm (CK) treatments and investigated the dry weights and nitrogen contents of plants, and mineral nitrogen concentrations in 0–5, 5–10 and 10–15cm depth of soil layers three times (4, 6 and 8 weeks from the beginning of the experiment, respectively). Results showed that earthworm activities significantly increased the dry weights and nitrogen contents of plants compared with CK. These results indicated that earthworm activities enhanced winter oilseed rape growth and nitrogen uptake before winter, which might be due to earthworm activities increased mineral nitrogen concentration in soils, altered the concentration ratio of NO3-N to NH4-N, increased plant root activity and leaf nitrate reductase activity as well as the interactions between them.
Article
This study investigates biomass, density, photosynthetic activity, and accumulation of nitrogen (N) and phosphorus (P) in three wetland plants (Canna indica, Typha augustifolia, and Phragmites austrail) in response to the introduction of the earthworm Eisenia fetida into a constructed wetland. The removal efficiency of N and P in constructed wetlands were also investigated. Results showed that the photosynthetic rate (P n), transpiration rate (T r), and stomatal conductance (S cond) of C. indica and P. austrail were (p < 0.05) significantly higher when earthworms were present. The addition of E. fetida increased the N uptake value by above-ground of C. indica, T. augustifolia, and P. australis by 185, 216, and 108 %, respectively; and its P uptake value increased by 300, 355, and 211 %, respectively. Earthworms could enhance photosynthetic activity, density, and biomass of wetland plants in constructed wetland, resulting in the higher N and P uptake. The addition of E. fetida into constructed wetland increased the removal efficiency of TN and TP by 10 and 7 %, respectively. The addition of earthworms into vertical flow constructed wetland increased the removal efficiency of TN and TP, which was related to higher photosynthetic activity and N and P uptake. The addition of earthworms into vertical flow constructed wetland and plant harvests could be the significantly sustainable N and P removal strategy.
Article
Earthworms mix soil layers and bind the soil with organic matter. This combination allows organic matter to disperse through the soil and also allows plants to access the nutrients they retains and enhance the soil’s fertility. Earthworms improve the soil’s biological, chemical, and physical characteristics and serve as soil conditioners. They do so by dissolution, aeration, soil organic breakdown, the release of plant nutrients, and their role in the fastening of nitrogen due to plant growth hormone secretion. However, a variety of soil and environmental factors influence the soil population. Furthermore, it remains uncertain how soil worms modify soil microbial communities’ composition and how they impact the soil’s microbial process. By feeding on microorganisms or selecting and stimulating specific microbial groups, earthworms reduce microbes’ activity and abundance. Earthworms directly impact the plant’s growth and recycling of nutrients but are mainly mediated by indirect microbial community change. Agricultural practices, including the use of pesticides, also contribute to the reduction in soil earthworms. There are no systematic associations among the abundance of earthworms, crop production, and contradictory influence on yield. Earthworms contain hormone-like substances, which encourage the health and growth of plants. This review presents the interaction of earthworms with soil fertility and different agricultural practices, including factors affecting earthworms’ population dynamics in all contexts that enable the adoption of acceptable environmental and earthworms-friendly farming practices for an optimum earthworm, productive, and fertile soil behavior.
Article
The response of growth characteristics (tillering number, plant height, stem diameter, leaf length, and leaf width), and nitrogen (N) and phosphorus (P) concentration of three wetland plants to the introduction of earthworms in a constructed wetland (CW) was investigated under greenhouse conditions. The growth characteristics, and N and P concentration of wetland plants were influenced by earthworms. The addition of earthworms enhanced three wetland plants growth, especially benefiting to the flower formation of the C. indica. The addition of earthworms to CW, the increased rate of plant height, stem diameter, leaf length, and leaf width could be summarized as follows: C. indica> P. australis > T.augustifolia. N and P concentration of Stems, leaves and flowers of wetland plants was increased by addition of earthworms into constructed wetland, and N and P concentration distributed in wetland plants followed the order of flowers> leaves > stems. The N and P removal rate could be enhanced by addition of earthworms into constructed wetland.
Conference Paper
A field experiment was conducted to investigate the effects of earthworms (Metaphire guillemi) on the seed yield and oil production of winter oilseed rape (Brassica napus L. cv. Zhongshuang No. 9), which was included inoculated with (E) or without (CK) earthworms treatments in three replicates. The result showed that earthworms significantly increased the seed yield of winter oilseed rape by 23.9% for individual plant and by 30.2% for whole plot levels, which might be due to earthworms significantly increased the pod numbers per plant (42.9%) compared with CK. The present study also showed that, although the seed oil content was significantly decreased by 4.8%, the oil production of winter oilseed rape was significantly increased at both the individual plant (18.1%) and whole plot (24.2%) levels since the increase in seed yield over-rode the decrease in oil content due to earthworm presence. The increased of plant growth and nitrogen (N) accumulation during the vegetative growth stages, and the increased translocation of N to seed during the maturation stages, because earthworms, might be responsible for the increased seed yield and oil production of winter oilseed rape.
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Chibui bari (Righi & Guerra, 1985) é um minhocuçu geófago, com tamanho até 60 cm, que tem como habitat vários solos no Acre. A atividade dessa espécie resulta na produção de grande quantidade de coprólitos ricos em nutrientes. O objetivo desta pesquisa foi avaliar o crescimento do milho em solo com presença da minhoca Chibui bari. O experimento foi conduzido em casa de vegetação da Universidade Federal do Acre, no município de Rio Branco, Acre, em 2009. O delineamento experimental foi inteiramente casualizado, com seis tratamentos (0, 1, 2, 3, 4 e 5 animais/tubo). O milho da variedade Bandeirante foi semeado em tubos de PVC com capacidade de 15,7 L, contendo solo de textura média. As variáveis avaliadas foram o diâmetro do colmo, as massas da matéria seca da parte aérea, da raiz e total das plantas, o teor de nutrientes no solo e a atividade microbiana. A presença de C. bari resultou em maiores diâmetro do colmo (13,29 %) e massas da matéria seca da parte aérea (28,73 %) e total (33 %) do milho. Contudo, não foi verificada mudança significativa na condição química e na atividade microbiana do solo, resultado que pode estar relacionado à maior exportação de nutrientes do solo, exigida pelo aumento do crescimento das plantas nos tratamentos com presença de minhocas.
Article
A pot trial was conducted to investigate the single, dual, and triple inoculation of earthworms or plant growth–promoting rhizobacteria (PGPR), including nitrogen-fixing bacteria (NFB) (Azotobacter chroococcum HKN-5) and phosphate-solubilizing bacteria (PSB) (Bacillus megaterium HKP-1), on the growth of Brassica parachinenesis and nitrogen (N) and phosphorus (P) availability in soils. All of the five inoculation treatments significantly (P B. parachinenesis. The greatest shoot and root biomass were recorded in the triple inoculation of earthworm, NFB, and PSB. All of the five inoculation treatments significantly (P 4 +)-N, NOx-N, and sodium bicarbonate (NaHCO3)–extractable P in soils. Based on plant growth and availability of N and P in soils, the present study suggested that the triple inoculation may be a promising approach for reducing the need for chemical fertilizers in growing vegetables.
Article
Intensive agriculture is often criticized for negative impacts on environment and human health. This issue may be solved by a better management of organisms living in crop fields. Here, we review the benefits of earthworms for crops, and we present techniques to increase earthworm abundance. The major points are the following: (1) Earthworms usually improve soil structural stability and soil porosity and reduce runoff. (2) Earthworms modify soil organic matter (SOM) and nutrient cycling. Specifically, earthworms stabilize SOM fractions within their casts, and they also increase the mineralization of organic matter in the short term by altering physical protection within aggregates and enhancing microbial activity. (3) The positive correlation between earthworm abundance and crop production is not systematic, and contrasting effects on yields have been observed. Earthworms induce the production of hormone-like substances that improve plant growth and health. (4) Direct drilling increases earthworm abundance and species diversity, but the beneficial effect of reduced tillage depends upon the species present and tillage intensity. (5) Organic amendments enhance earthworm abundance. (6) Earthworms feeding at soil surface are the most exposed to pesticides and other agrochemicals. Finally, we discuss how to combine management practices, including inoculation, to increase the earthworm services. We conclude that using earthworm services in cropping systems has potential to boost agricultural sustainability.
Article
Vermicomposting is considered a clean, sustainable, and effective technology to recycle food waste. However, the current knowledge of how different food waste combinations produce high-quality compost remains poor. Hence, the present study investigated the vermicomposting of soybean meal (SM) waste with sugarcane bagasse (SCB) in different ratios of SM:SMB (v/v, based on dry weight), i.e., 0:100, 25:75, 50:50, 75:25, and 100:0. Vermicompost quality was evaluated based on its maturity, agrochemical properties, earthworm (Eisenia fetida) biomass, and reproduction. The results showed that SM increased the activities of dehydrogenase, acid- and alkaline- phosphatase, and urease while decreasing the activity of cellulose. The β-glucosidase activity was highest with 25:75, followed by 50:50 of SM:SCB ratio. A higher proportion of SM increased the mineralization and nitrification rate during the vermicomposting, whereas total and available nutrients contents increased in the final product. The concentration of all heavy metals in the final vermicomposts was below than threshold. The degree of polymerization (DP) showed that all of the final vermicomposts were sufficiently mature for agricultural application. A higher percentage of SCB (≥50%) in SM:SMB mixtures, however, resulted in best vermicompost owing to reduced pH and EC, increased CEC and humic substance concentration, and higher germination index. So far, earthworm mass and abundance were highest in SM:SCB ratio of 50: 50. In short, a 50:50 mixture of SM:SCB promoted earthworm growth and produced the best quality vermicompost.
Article
The effect of four vermicomposts, obtained from different organic sources (pistachio waste [PWV], date waste [DWV], cattle manure waste [CMV], and food waste [FWV]), as well as two chemical fertilizers (complete fertilizer [CF] and NPK fertilizer [NPK]) on some life history traits of the sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) was investigated in a series of choice and not choice experiments. In a choice experiment, adult whiteflies exhibited significantly lower preference for settling and oviposition on plants treated with vermicomposts than those in control, CF, and NPK groups (P < 0.01), with better results were observed in PWV group. In no choice experiment, adult whiteflies laid significantly fewer eggs in PWV group in comparison with control, CF, and NPK groups (P < 0.01); other treatments had intermediary values. Fertilization had a significant effect on the preadult development time of sweetpotato whitefly, with the longest development times were recorded for plants treated with PWV (24.65 d) and FWV (22.04 d), respectively. The preadult mortality of sweetpotato whitefly increased significantly following fertilization, with the greatest mortal effects were observed in PWV (54.11%) and DWV (44.68%) groups, respectively. Plants fertilized with PWV had significantly higher phenolic content (10 mg/ml) than control (BAGA; 6.08 mg/ml), while those in CMV group exhibited intermediary value (7.28 mg/ml). Altogether, results of this study reveal both antixenosis (nonpreference) and antibiosis (decreased survival and prolonged development time) resistance of tomato plants mediated by vermicomposts. Particularly, plants treated with PWV obtained the best results in terms of both growth and resistance to sweetpotato whitefly.
Chapter
In the last two decades, many countries have recognized the hazards of persistent organic pollutants (POPs) and have banned or restricted their use and production. Among these persistent toxic substances, endosulfan has been widely used in the agriculture sector in Pakistan for more than 35 years to control pests. As a signatory of Stockholm Convention (SC), Pakistan has recently phased out; reduced/eliminated and destructed existing obsolete POPs pesticides across the country. This book chapter focuses on the current situation of endosulfan in Pakistan with the emphasis on its historical usage and toxicity effects on environment and human. Needed policy and possible measures should be implemented at governmental level to avoid the increasing problem of endosulfan in the country. Available literature highlights that there is still a general lack of reliable data and research studies addressing endosulfan related issues in the context of environmental and human health risks in Pakistan. Therefore, there is a critical need to improve the current knowledge base, build upon the research experience from other countries which have experienced similar situations in the past. Further research into these issues in Pakistan is considered vital to help inform future policies/control strategies as already successfully implemented in other countries. Keywords: Endosulfan; Historical usage, Environmental risks, Persistent organic pollutants, Pests, Human health
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Abstract The soil microbial community plays a vital role in the biogeochemical cycles of bioelements and maintaining healthy soil conditions in agricultural ecosystems. However, how the soil microbial community responds to mitigation measures for continuous cropping obstacles remains largely unknown. Here we examined the impact of quicklime (QL), chemical fungicide (CF), inoculation with earthworm (IE), and a biocontrol agent (BA) on the soil microbial community structure, and the effects toward alleviating crop yield decline in lily. High-throughput sequencing of the 16S rRNA gene from the lily rhizosphere after 3 years of continuous cropping was performed using the Illumina MiSeq platform. The results showed that Proteobacteria, Acidobacteria, Bacteroidetes, Actinobacteria, Chloroflexi and Gemmatimonadetes were the dominant bacterial phyla, with a total relative abundance of 86.15–91.59%. On the other hand, Betaproteobacteriales, Rhizobiales, Myxococcales, Gemmatimonadales, Xanthomonadales, and Micropepsales were the dominant orders with a relative abundance of 28.23–37.89%. The hydrogen ion concentration (pH) and available phosphorus (AP) were the key factors affecting the structure and diversity of the bacterial community. The yield of continuous cropping lily with using similar treatments decreased yearly for the leaf blight, but that of IE was significantly (p
Chapter
Earthworms have extremely important influences on soil structure, fertility, and productivity, in forming aggregates; improving soil physical conditions; providing channels and burrows for drainage, aeration, and root growth; increasing water-holding capacity; and generally improving plant growth and nutrient uptake. It is generally agreed that earthworms play an important role in improving soil structure with considerable benefits to soil fertility and crop productivity. Earthworms also improve soil fertility by accelerating the decomposition of plant litter and soil organic matter and releasing nutrients in forms that are readily available for uptake by plants. Biofertilizers derived from earthworms improve the functional diversity of soil and by effect improve soil respiration, microbial biomass, and enzymatic activity. It is difficult in practice to separate the diverse biological effects of earthworms on soils and plants from their abiotic effects, but most research addresses these aspects separately. The great influence of earthworms on nutrient availability and organic matter cycles and through their interactions with soil microorganisms in the decomposition of organic matter are discussed more fully in Chaps. 8 and 9. In this chapter, burrowing behavior and its mechanics are discussed as well as its variability among species. Earthworms also greatly influence the soil structure by ingestion of soil, partial breakdown of organic matter, release of nutrients, mixing of these fractions and ejection of the material as rich, stable surface or subsurface casts, and burrowing and bringing subsoil to the surface. Water-stable soil aggregates are also formed by earthworms which resist breakdown when exposed to internal or external stress like wetting, drying, compression, or other physical disturbance. Diverse observations of earthworms’ effects on soil erosion are also discussed such as earthworms’ ability to reduce sediment load of runoff. Evidence that earthworms increase plant productivity in the form of increased germination, growth, and yields of crops is discussed herein.
Article
Earthworms are abundant and ecologically very important organisms in the soil ecosystem. Impacts by pollutants on earthworm communities greatly influence the fertility of the terrestrial environment. In ecotoxicology, earthworms are good indicators of metal pollution. The observed median lethal concentrations (LC50) and the effective concentrations that cause 50 % reduction of earthworm growth and reproduction (EC50) are referred to as toxicity concentrations or endpoints. In addition, the 'no observed effective concentration' (NOEC) is the estimation of the toxicity of metals on earthworms expressed as the highest concentration tested that does not show effects on growth and reproduction compared to controls. This article reviews the ecotoxicological parameters of LC50, EC50 and NOEC of a set of worms exposed to a number of metals in various tested media. In addition, this article reviews metal accumulation and the influences of soil characteristics on metal accumulation in earthworms. Morphological and behavioural responses are often used in earthworm toxicity studies. Therefore, earthworm responses due to metal toxicity are also discussed in this article.
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We established a long-term field experiment in 1991 to investigate the influence of earthworms on C and N cycling processes in agroecosystems. In a replicated field experiment we decreased earthworm populations using electroshocking, increased them by adding field-collected worms or left them unmanipulated. Population manipulations and sampling were done twice per year in 20 m2 field enclosures that were made from sheets of PVC buried 45 cm deep and extending 15 cm above the soil surface. The experiment was established in maize (Zea mays) agroecosystems in which N was provided in the form of NH4NO3N, cow-manure-N or legume-cover-crop-N. The two dominant earthworm species at the site were Lumbricus terrestris and Aporrectodea tuberculata. Electroshocking was effective at reducing earthworm populations to about 25% of their natural abundance. In the autumn of 1993, electroshocked enclosures had 75% fewer earthworms and 65% less earthworm biomass than plots with unmodified populations. Electroshocking was equally effective at reducing populations of all earthworm species and did not alter the relative species abundance. The addition of field-collected worms was not as effective at increasing earthworm populations as electroshocking was at reducing populations. Enclosures with added earthworms had 1.17-fold more earthworms and 2.18-fold greater earthworm biomass than control enclosures. The biomass of L. terrestris was significantly greater in enclosures with increased earthworm populations than in enclosures with reduced or unmodified populations; the biomass of A. tuberculata was not increased. Total earthworm biomass at the site declined from nearly 90 g m−2 in the spring of 1991 to < 30 g m−2 in the autumn of 1993, probably due to: (1) extreme climatic conditions, including severe droughts in the summers of 1991 and 1993 and a period of excessive rain in the summer of 1992; and (2) the conversion of the field from perennial alfalfa (Medicago sativa) to cultivated maize. The manipulation of earthworm populations in large-scale, replicated field experiments provides a unique and successful approach for investigating the effects of earthworms on soil structure and nutrient cycling processes.
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Plants compete for limited resources. Although nutrient availability for plants is affected by resource distribution and soil organisms, surprisingly few studies investigate their combined effects on plant growth and competition. Effects of endogeic earthworms (Aporrectodea jassyensis), root-knot nematodes (Meloidogyne incognita) and the spatial distribution of 15N labelled grass litter on the competition between a grass (Lolium perenne), a forb (Plantago lanceolata) and a legume (Trifolium repens) were investigated in the greenhouse. Earthworms promoted N uptake and growth of L. perenne. Contrastingly, shoot biomass and N uptake of T. repens decreased in the presence of earthworms. P. lanceolata was not affected by the earthworms. We suggest that earthworms enhanced the competitive ability of L. perenne against T. repens. Nematodes increased the proportion of litter N in each of the plant species. Litter distribution (homogeneous vs. patch) did not affect the biomass of any plant species. However, P. lanceolata took up more 15N, when the litter was homogeneously mixed into the soil. The results suggest that endogeic earthworms may affect plant competition by promoting individual plant species. More studies including decomposers are necessary to understand their role in determining plant community structure.
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European earthworms are colonizing worm-free hardwood forests across North America. Leading edges of earthworm invasion in forests of northern Minnesota provide a rare opportunity to document changes in soil characteristics as earthworm invasions are occurring. Across leading edges of earthworm invasion in four northern hardwood stands, increasing total earthworm biomass was associated with rapid disappearance of the O horizon. Concurrently, the thickness, bulk density and total soil organic matter content of the A horizon increased, and it’s percent organic matter and fine root density decreased. Different earthworm species assemblages influenced the magnitude and type of change in these soil parameters. Soil N and P availability were lower in plots with high earthworm biomass compared to plots with low worm biomass. Decreases in soil nitrogen availability associated with high earthworm biomass were reflected in decreased foliar nitrogen content for Carex pensylvanica, Acer saccharum and Asarum canadense but increased foliar N for Athyrium felix-femina. Overall, high earthworm biomass resulted in increased foliar carbon to nitrogen ratios. The effects of earthworm species assemblages on forest soil properties are related to their feeding and burrowing habits in addition to effects related to total biomass. The potential for large ecosystem consequences following exotic earthworm invasion has only recently been recognized by forest ecologists. In the face of rapid change and multiple pressures on native forest ecosystems, the impacts of earthworm invasion on forest soil structure and function must be considered.
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Responses of soil N pools to field manipulation of earthworm populations (reduced, unaltered or increased each spring and autumn) were evaluated within each of three agroecosystems based on different N sources: NH4NO3 fertilizer, cow manure or a legume-rye winter cover crop. Our objectives were to determine the effects of earthworms on soil N dynamics in agroecosystems based on different organic or inorganic sources of N, and to examine potential interactive effects of agroecosystem treatments and field-scale earthworm manipulations on soil N pools and potential N losses. Earthworm manipulations began in spring 1991, and were repeated each spring and fall. Soil microbial biomass N was determined by fumigation-extraction on six dates in 1992 and four dates in 1993. Extractable inorganic soil N (0–15 cm) was measured in January and approximately every 2 weeks during the growing seasons of 1992 and 1993. Additionally, the post-growing season vertical distribution (0–15, 15–30, and 30–45 cm) of extractable soil NO3N was evaluated in November of 1992 and 1993. Earthworm manipulations affected microbial biomass N and extractable inorganic N pools in bulk soil samples. Microbial biomass N was significantly higher in the earthworm reduction treatments. There were significant earthworm × agroecosystem interactions affecting soil NO3. In the inorganically fertilized system, earthworm additions resulted in elevated amounts of extractable NO3 during the growing season of both years. Extractable NH4 concentrations were increased by earthworm additions in 1993, but only in the inorganically fertilized system. Earthworm additions also increased the concentration of soil NO3 at lower depths after the growing season, especially in the inorganically fertilized system. These results suggest that earthworms can alter N cycling processes in agroecosystems, and that these changes are sufficient to be detected by bulk soil sampling. Our results also indicate that the net effects of earthworm activity can vary with agroecosystem management practices. Earthworms may increase N availability by reducing microbial immobilization and enhancing mineralization. However, increased amounts of soil NO3 at the end of the growing season, and increased concentrations in lower soil horizons, could lead to increased leaching losses from inorganically fertilized systems. The implications of these changes for ecosystem-level nutrient fluxes will require further investigation.
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We designed a microcosm experiment to investigate the effects of earthworms on N cycling processes and microbial activity, in soil receiving organic or inorganic nutrient amendments. Cylindrical microcosms contained 16l. of field-collected soil that received 1 of 3 nutrient amendments, added to the upper 5 cm of soil at a rate of 150 kg N ha−1; (1) granular NH4NO3 fertilizer; (2) straw-packed dairy cow manure; and (3) air-dried hairy vetch (Vicia villosa) legume residue. There were 4 replicates of each nutrient treatment without earthworms, and 4 replicates with a total of 21 earthworms added per microcosm (a mixed community of Lumbricus terrestris and Aporrectodea tuberculata). The microcosms were incubated for 112 days. Soil respiration was measured continuously and extractable NO3− and NH4+ and microbial biomass-N were measured, periodically, at 0–5 and 5–15 cm. Earthworms had significant effects on amounts of extractable NO3−, which increased with time, and were greatest in soil that received NH4NO3 fertilizer and least in soil that received legume residues. On the final sample date (112 days), earthworms increased amounts of extractable NO3− at the 0–5 cm soil depth 1.83-, 1.88- and 1.26-fold in microcosms supplied with NH4NO3, manure and legume trestments, respectively. Earthworms increased the amounts of extractable NH4+, after 112 days, at the 0–5 cm soil depth, by 1.60-, 4.00- and 1.30-fold, in microcosms that had received the NH4NO3, manure and legume treatments, respectively. Earthworms significantly reduced the amounts of microbial biomass-N at the 5–15 cm soil depth, and this effect was greatest in microcosms that had received the NH4NO3 and manure treatments. Earthworms increased soil respiration rates during the first 15 days by from 1.24- to 2.42-fold and increased cumulative soil respiration (112 days) by 1.84-, 1.37- and 1.24-fold, respectively, in microcosms treated with the fertilizer, manure and legume treatment. These results indicate earthworms increased the amounts of extractable N by feeding on the microbial biomass, and increasing the turnover and mineralization of microbial tissues.
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Cette revue place au centre des interactions entre les plantes, les animaux et les microorganismes du sol, les invertébrés abondants et de grande taille qui ingèrent des particules organiques et minérales produisant ainsi des structures durables. Ces invertébrés sont appelés organismes ingénieurs du sol et les données disponibles sur leur abondance, leur distribution géographique et leurs rôles fonctionnels montrent que les vers de terre et les termites en sont les principaux représentants. Ils influencent la diversité et l'activité des organismes appartenant à des groupes fonctionnels subordonnés, les transformateurs de litière, les microprédateurs et les microorganismes, régulant ainsi les transformations de nutriments. Les liens entre l'activité et la diversité des ingénieurs et les propriétés physiques du sol sont détaillés ; une mention particulière est faite de leurs effets sur l'hétérogénéité du sol, sa stabilité structurale, la distribution de la matière organique dans le profil, l'infiltration et la rétention de l'eau. Il est probable que les changements globaux attendus affecteront l'abondance et la diversité des organismes ingénieurs par le biais de la quantité et de la qualité de la litière et d'autres effets liés aux modifications des plantes et de leurs peuplements. Les changements de température attendus pourraient élargir la distribution latitudinale des termites et favoriser les termites humivores et les vers de terre endogés à régime géophage. Dans certaines régions, cependant, ces changements ne pourront s'observer car la faune locale ne comprend pas de représentants de ces groupes. Dans l'immédiat, c'est surtout l'intensification de l'usage des terres et en particulier, la perturbation des milieux forestiers qui est préoccupante car des modifications de l'équilibre des groupes fonctionnels d'organismes ingénieurs s'observent déjà... (D'après résumé d'auteur)
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Some root parameters such as distribution, length, diameter and dry matter are inherent to plant species. Roots can influence microbial population during vegetative cycle through the rhizodeposits and, after senescence, integrating the soil organic matter pool. Since they represent labile substrates, especially regarding nitrogen, they can determine the rate of nutrient availability to the next crop cultivated under no-tillage (NT). The root systems of two crop species: maize (Zea mays L.) cultivar Cargill 909 and soybean [Glycine max (L.) Merr.] cultivar Embrapa 59, were compared in the field, and their influence on spatial distribution of the microbial C and N in a clayey-textured Typic Hapludox cultivated for 22 years under NT, at Tibagi, State of Paraná (PR), Brazil, was determined. Digital image processing and nail-plate techniques were used to evaluate 40 plots of a 80 ´ 50 ´ 3 cm soil profile. It was observed that 36% and 30% of the maize and soybeans roots, respectively, are concentrated in the 0 to 10 cm soil layer. The percent distribution of root dry matter was similar for both crops. The maize roots presented a total of 1,324 kg C ha-1 and 58 kg N ha-1, with higher root dry matter density and more roots in decomposition in the upper soil layer, decreasing with depth. The soybean roots (392 kg C ha-1 and 21 kg N ha-1) showed higher number of thinner roots and higher density per length unity compared to the maize. The maize roots enhanced microbial-C down to deeper soil layers than did the soybean roots. The microbial N presented a better correlation with the concentration of thin active roots and with roots in decomposition or in indefinite shape, possibly because of higher concentration of C and N easily assimilated by soil microorganisms.
Article
From the moment that soil is consumed by or enters into contact with an earthworm, either superficially or internally, physicochemical and microbiological changes take place. Furthermore, when seeds germinate, they immediately come into contact with soil microorganisms, and as the plant roots grow, microorganisms promote changes in the soil physicochemical and microbiological environment. The three-way plant-microbe-invertebrate interactions that follow have profound effects on the growth and development of plants, soil microorganisms, and invertebrate communities.
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Large earthworms consume substantial numbers of seeds, above and below ground. Many are deposited in a viable state in wormcasts on the soil surface. Such wormcasts apparently provide particularly favourable conditions for seedling establishment. Plants with seeds that are readily ingested by earthworms are likely to be at an advantage over other species in at least some communities. This neglected area of plant-animal interactions lends itself well to student projects, a number of which are suggested. Such investigations could yield valuable new information, with implications for turf management and the composition of natural communities.
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There has been an exponential increase in research publications addressing the impact of earthworms on terrestrial nutrient cycling processes. This research has demonstrated that earthworms significantly affect key soil properties and processes such as microbial biomass and activity, organic matter dynamics, nutrient availability, plant uptake and production, and soil structure. There is sufficient evidence to conclude that earthworms are central to regulating nutrient cycling processes in many ecosystems. Earthworms may alter the balance between conservation and loss of nutrients in ecosystems, and their net influence at large scales defines their role in ecosystem processes. Many investigations have focused on small-scale phenomena, such as nutrient dynamics in earthworm casts and burrows, that are critical to a mechanistic understanding of earthworm effects but are difficult to extrapolate to the ecosystem scale. In addition to the challenge of integrating information and analysis across spatial scales, there is the challenge of extrapolating the short-term effects of earthworms through time, which, as Darwin (1881) noted more than a century ago, can lead to cumulative changes at the landscape scale.
Article
A method is described for caging earthworms in undisturbed soil in field experiments. The method is applicable to sites which are seasonally dry (e.g. summer in southern Australia). Cages were made from sections of PVC pipe (20 cm long × 30 cm dia) which were driven vertically into the soil beneath a permanent pasture in South Australia during spring when the soil was moist and resident earthworms were active near the surface. During the following summer, when most resident earthworms had burrowed below the depth of the pipes to escape surface aridity, the pipes and the soil within them were lifted from the surrounding soil. Fine curtain mesh was strapped across the bottom edges of the pipes and the resultant “cages” were then replaced in their holes. The mesh isolated the soil within the cages and prevented escape or invasion of earthworms during the subsequent wet season when the desired earthworm species were added. The method was used to compare: (1) the influences of surface-applied lime and sheep dung on the establishment of two earthworm species, Aporrectodea longa (Lumbricidae) and Spenceriella sp. (Megascolecidae); (2) the abilities of the same two earthworm species to bury lime and dung; and (3) the relative influences of A. caliginosa, A. longa, A. rosea, A. trapezoides and Spenceriella sp. on pasture production. The earthworms were caged for 5 months. Survivorship of all species was good (⩾ 50%). Contamination in the cages by undesired species was small (<20%). The addition of sheep dung enhanced the establishment of A. longa (greater numbers and biomass) but not the establishment of Spenceriella sp. The addition of lime did not influence the establishment of either A. longa or Spenceriella sp. A. longa buried lime and dung more readily than did Spenceriella sp. Pasture production was greater in the presence of A. longa and dung than in other treatments.
Article
Mechanical incorporation of surface-applied lime (CaCO3) to ameliorate subsoil acidity is often not feasible because of damage to plants and erosion hazards. This paper presents results of a field cage experiment comparing the influences of three exotic European earthworm species (Aporrectodea longa, A. caliginosa and A. trapezoides) on lime incorporation and pasture production over two seasons, on two acidic soil types under pastures on the central tablelands of New South Wales, Australia. A. trapezoides was least effective in increasing pH of soil below 2.5 cm and survived poorly compared with A. caliginosa. The latter was most effective at 2.5–10 cm whilst A. longa was more effective at 10–15 cm depth. Similar complementary increases in the level of mineralisable nitrogen (MN) by both earthworm species were also observed. There was evidence suggesting that the survival of A. longa was improved by the presence of A. caliginosa. Earthworms improved pasture growth at only one site.
Article
The CHCl3 fumigation-extraction method for determining soil microbial N involves the extraction of CHCl3-fumigated and CHCl3-unfumigated samples with 0.5 M K2SO4, followed by determination of total N in the extracts. Total N is typically determined by Kjeldahl digestion (TKN) with the inclusion of NO2- and NO3- present. The determination of total N by TKN has several procedural constraints such as an initial concentration step, long digestion times, and considerable bumping caused by catalyst salts. In contrast, a persulfate oxidation method (TPN) commonly used for determination of total N in sea- and freshwater samples does not require a concentration step and is much simpler and faster than TKN. The objective of this study was to evaluate and adapt the TPN method to measure total N in 0.5 M K2SO4 extracts for determination of soil microbial biomass N. Studies were conducted to optimize reagent/sample (R/S) ratio and autoclaving time, and to evaluate the effects of C and N concentrations. These studies showed that complete N recovery can be obtained with a R/S ratio of 1 and an autoclaving time of 30 min in extracts containing as much as 250 mg glucose-C L-1 at a C/N ratio of 10:1. A comparison of the optimized TPN method to TKN for extracts of 12 CHCL3-fumigated soils indicated that the methods gave the same N recoveries. The use of the TPN method in 0.5 M K2SO4 extracts should facilitate more rapid and efficient measurements of soil microbial biomass N.
Article
A digestion mixture suitable for the decomposition of soil and plant materials is described. This is based on sulphuric acid and hydrogen peroxide as oxidants with the addition of lithium sulphate to elevate the digestion temperature and selenium as catalyst. The subsequent solution is suitable for the determination of nitrogen, phosphorus and most mineral ions. A series of tests have been carried out to determine optimum conditions and check elemental recoveries and the procedure is compared with alternative systems.
Article
Most of the earthworms now found in agricultural fields in south-eastern Australia are exotic, patchily distributed, mineral soil dwellers (endogeic species). The influence of two of the most common endogeic species, Aporrectodea caliginosa and A. trapezoides, on pasture production was compared with that of another exotic, surface-feeding, deep-burrowing (anecic) species, A. longa, which is essentially restricted in its Australian distribution to Tasmania. Comparisons were made by introducing 4 different densities of the worms in cages at 10 field sites and measuring pasture production for approximately 5 months. All 3 species increased pasture production at most of the 10 sites. Increases in pasture production were greatest where original pasture production was low. Pasture production increased with earthworm density. Averaged across sites, earthworms increased pasture production by up to 61%. Significant increases in yield were detected with ≥214 A. longa/m 2 and ≥429 A. caliginosa or A. trapezoides/m 2. A. longa is a much bigger worm than A. caliginosa and A. trapezoides. If the initial number of worms introduced to the cages was taken as the measure of earthworm ‘abundance’, then A. longa increased pasture production more than the 2 endogeic species. If the biomass of introduced worms was taken as the measure of abundance, then the reverse was the case. A. longa reduced nitrogen levels in some soils. Phosphorus levels were not affected. No residual effects on pasture production were detected when soil that had been improved by earthworms was potted and resown with ryegrass. Broad scale introduction of A. caliginosa, A. longa, or A. trapezoides to sites lacking them in south-eastern Australia is likely to improve pasture production significantly. Addition of A. longa to existing communities of endogeic species should further increase pasture yield by enhancing functional diversity.
Article
The earthworm fauna of pastures in south-eastern Australia is dominated by exotic lumbricid earthworms, in particular the endogeic species, Aporrectodea caliginosa and A. trapezoides. Anecic species such as A. longa are very rare. All 3 species were introduced within cages in 10 pastures on a range of soil types within the region. Five months later, A. longa had generally survived the best and A. trapezoides the worst. The survivals and weights of individual worms varied between sites for all 3 species. The survivals of A. caliginosa and A. longa, and to a lesser extent A. trapezoides, were positively correlated with soil clay content. The weights of A. caliginosa and A. longa, but not A. trapezoides, were positively correlated with soil P content. The survivals and weights of A. longa and A. trapezoides and the weights only of A. caliginosa decreased with increasing inoculation density, suggesting increased intraspecific competition for resources, particularly in the first two species. A. longa reduced the abundance and biomass of the exotic acanthodrilid earthworm, Microscolex dubius, at one site, and the total biomass of 3 native megascolecid species at another, when these latter species occurred as contaminants in A. longa cages. The addition of lime had no effect on the survivals and weights of A. caliginosa, A. longa, and A. trapezoides, although the soils were acid at the sites tested. The addition of sheep dung increased the survival and weights of some species at some sites. Mechanical disturbance of the soil within cages reduced the survivals of A. longa and A. trapezoides. A. longa was released without being caged at 25 sites within one pasture in South Australia. Four years later, it was recovered at all release points. A. longa has the potential to colonise pastures widely throughout the higher rainfall regions of south-eastern Australia.
Article
Earthworms were added to enclosures in two agroecosystems to determine their influence on soil nitrogen availability and microbial activity, and to quantify their effect on the leaching of water and nitrogen through the surface soil. The two agroecosystems were a corn-soybean rotation with chisel-plow-disk tillage following corn (CS), and a corn-soybean-wheat-vetch rotation with ridge-tillage (CSW). In both agroecosystems, earthworm additions in the fall (100 m−2) led to more abundant deepdwelling earthworms and less abundant surface-dwelling earthworms than in enclosures with no additions, but had little effect on total earthworm abundance after 5 months. In the CS system, earthworm additions led to greater concentrations of potentially mineralizable nitrogen (PMN) and microbial biomass nitrogen (MBN) in the surface soil than in control enclosures in the following spring. In the CSW system, earthworm additions led to greater overall concentrations of dissolved organic nitrogen (DON), but only to localized changes in PMN and MBN at different positions within crop rows and at different soil depths. Soil mineral nitrogen concentrations were not influenced by earthworm additions. Earthworms significantly influenced soil microbial activity in both agroecosystems; earthworm additions generally increased soil dehydrogenase activity (DHA) in the CS system, and reduced it in the CSW system, compared to controls. Earthworm additions led to 4- to 12-fold increases in the volume of soil leachate collected during 1 week in zero-tension pan lysimeters buried 45 cm deep. For both agroecosystems, nitrogen flux in leachate was increased by nearly 10-fold in response to earthworm additions. Most of this response was due to increased flux of DON. We conclude that the composition of earthworm communities can strongly influence the availability and leaching of nitrogen in the surface soil of some grain-crop agroecosystems, at least in the short-term. More work is needed to predict the longer-term consequences of earthworms on crop productivity, nitrogen use efficiency and groundwater quality.
Article
The kEN value (= extractable part of microbial biomass N after fumigation) of the fumigation-extraction method was assessed using the C-to-N ratio of the organic matter which was rendered extractable by CHCl3 fumigation. The data for this calibration approach was obtained from 51 arable and 23 grassland soils. The second calibration approach was to compare the relationship between N rendered extractable by CHCl3 fumigation and the C-to-N ratio measured in the flush of the fumigation-incubation method by recalculating data obtained from the literature. On the basis of these two approaches, we recommend using a kEN value of 0.54 as originally proposed by Brookes et al. (Soil Biology & Biochemistry17, 837–842, 1985).
Article
The objectives of this study were (1) to evaluate the effect of earthworm activity on aboveground plant biomass production of native calcareous grassland communities in NW-Switzerland and (2) to determine which plant functional types (graminoids, non-legume forbs and legumes) are most responsive as indicators of potential effects on plant community structure. Earthworm activity was manipulated in the field by creating three earthworm densities (low: 37, ambient: 114, high: 169 worms m⁻²) and two soil moisture conditions (ambient and 280 mm yr⁻¹ additional rain) in 30 1×1 m² trenched plots (to a depth of 45 cm with nylon screening). Earthworm density was censused and readjusted in the spring and autumn of 1996 and again in the spring of 1997 using the Octet electro-sampling method. Earthworm activity, measured as cumulative surface cast production, was significantly different among worm density treatments (low worm density: 591±49, ambient: 991±87, high: 1469±120 g cast d.m. m⁻² yr⁻¹), P<0.001. Cast production increased with increasing worm density, however increased soil moisture, which was significantly higher in plots receiving additional rain, did not affect worm activity at any worm density level. Surprisingly, earthworm activity had no effect on the aboveground biomass production of the plant community or of any plant functional type; however additional rain stimulated aboveground biomass production of graminoids (+30%, P=0.006) and Carex spp. (+200%, P=0.020). The lack of a stimulatory effect of increased earthworm activity on plant biomass production indicates that apparent earthworm-induced increases in plant nutrient availability were insufficient to promote the growth of the perennial plant species in these native grasslands. Our results, taken together with those from earlier studies in these grasslands, suggest that the effects of earthworm activity on plant community structure occur slowly where they relieve soil constraints on plant growth.
Article
Earthworms are important, beneficial invertebrates in turfgrass, where their burrowing and feeding activity enhances soil structure and fertility and incorporates thatch and other plant residues into the soil. The comparative toxicity of 17 commonly used turfgrass pesticides and recovery of earthworm populations following exposure were studied for 2 yr in Kentucky bluegrass turf. A single application of the fungicide benomyl or the insecticides ethoprop, carbaryl, or bendiocarb at labeled rates reduced earthworm populations by 60- 99%, with significant effects lasting for at least 20 wk. These compounds also significantly reduced the rate at which earthworms incorporated mineral soil into buried pieces of thatch. Other insecticides, specifically diazinon, isofenphos, trichlorfon, chlorpyrifos. and isazophos caused less severe, but significant earthworm mortality in some tests. None of the herbicides tested significantly affected earthworm populations. The abundance of Cryptostigmata, Collembola, and ants also was drastically reduced by some treatments. Preservation of earthworms and other beneficial soil invertebrates may be critical to long-term stability of the turfgrass ecosystem.
Article
WHILE investigating the removal of leaves by earthworms from the soil surface of some apple orchards at Wisbech (Cambs.) an estimate of the population of Lumbricus terrestris was needed because it seemed to be the only species present that pulled apple leaves into its burrows. L. terrestris burrows deeply in the light, well-drained soil of the Wisbech area, and a population estimate made by removing and hand-sorting soil samples was impracticable because of the depth of the burrows into which the worms retreat when soil samples are removed. The permanganate method used by Evans and Guild1 has been shown by Svendsen2 greatly to under-estimate the population and my tests at Wisbech confirmed this.
Article
 Traditional tree fallows have been abandoned on the western coast of the Reunion Island because of the increasing need for cultivated land. Soil fertility is no longer restored and crop yields have decreased drastically. The leguminous plant, Lotus uliginosus (trefoil), used as a cover crop, has made possible the control of erosion, the restoration of soil macrofauna, especially earthworms, and the increase in crop yields. When trefoil was associated with earthworms (Amynthas corticis), the densities of maize, the yields of maize stalk and dry matter, the yield of trefoil fodder dry matter, and the biomass and respiratory activity of soil microflora were considerably increased. The combined effects of their association led to a significant decrease in populations of the plant-parasitic nematode, Pratylenchus vulnus, in maize roots, and in the population of borers. Some soil chemical features were modified.
Article
Pastures in southern Australia are dominated by endogeic earthworms such as Aporrectodea caliginosa (Sav.). Introductions of the anecic earthworm, A. longa (Ude), which is mostly restricted to Tasmania at present, are likely to increase the functional diversity of local communities and thereby enhance plant production and agricultural sustainability. However, the potential impact of A. longa on resident earthworm communities first needs assessing. Glasshouse and field experiments reported here suggested that A. longa can reduce the abundance and biomass of A. caliginosa, but that these effects are likely to be offset by overall increases in worm abundance. There was no evidence to suggest that species richness was reduced by A. longa introduction.
Article
Results are reported from an experiment comparing the effects of earthworm manipulations and agroecosystem fertility treatments on corn (maize, Zea mays) and weed biomass, and on nitrogen content. The experimental design consisted of inorganic (ammonium nitrate) and organic (cover crop and manure) fertility treatments. Within each fertility treatment, earthworm manipulations consisted of ambient, augmented and reduced populations. Both ambient and augmented earthworm population treatments resulted in greater weed biomass compared to earthworm reductions. Early season crop biomass was significantly influenced by earthworm reductions. Early season crop biomass was significantly influenced by earthworm × N source interactions, with greater maize biomass in the earthworm reduction treatment. In fertilizer and manure treatments, grain yields were higher in the reduced earthworm treatment compared to either augmented or ambient earthworm treatments. This effect on yields was probably related to interactions with the weeds and damage to the maize by an insect pest.
Article
Earthworms are important members of the decomposer food web in a wide range of sites. Previous field investigations on the development of earthworm populations of mine soils in the Lusatian coal mining region, Germany, have shown quite small population densities in quaternary sands and less or even no earthworms present in sandy soils derived from tertiary deposits. The aim of the present investigation was to improve the development of earthworm populations in mine soils from tertiary deposits by applying various types and amounts of organic waste residues, such as sewage sludge, composted sewage sludge, and green waste derived compost. Additionally, we were interested in the stimulation effect of organic waste materials on parameters of earthworm activity, such as food consumption and burrowing activity. The investigations were carried out in field mesocosms and laboratory experiments (microcosms; observation cages). In general, the population density, fresh biomass, food consumption, and the burrowing activity of earthworms were significantly improved by the application of the various organic waste materials compared with mineral fertilizers. Fresh sewage sludge in addition to composted sewage sludge were found to be the most favourable organic waste residues compared with green waste derived composts. The addition of brown coal sludge to sewage sludge did not reduced the stimulation effect. There was considerable variation in the population structure of a defined earthworm community which was exposed in the mesocosms during a two year period in relation to the types and amounts of the organic waste materials applied.
Article
A field survey was conducted to determine the numbers and biomass of earthworms in soils receiving different tillage and cropping treatments, and to investigate in a greenhouse study the effect of earthworms on the rate of breakdown of soybean (Glycine max) and maize (Zea mays L.) residues. The numbers and biomass of earthworms under continuous soybeans were greater than those present under maize, possibly due to the adverse effects of insecticide and anhydrous ammonia fertilizer used with maize. No-tillage doubled the population of earthworms under soybeans, when compared with ploughing. Numbers (141 m−2) and biomass (26.5 g m−2) of earthworms under no-till soybeans were still much lower than the numbers (1298 m−2) and biomass (224.5 g m−2) under pasture receiving heavy applications of animal manure. Using 16-1 pots in the greenhouse, the effect of 0, 15 (250m−2) and 30 (500m−2) earthworms (Lumbricus rubellus) pot−1 on the rate of breakdown during 54 days of 50 g of soybean or maize residues in the Raub silt loam (Aquic Argiudoll) was studied. At 36 days, 60% of the soybean residues were recovered from pots to which no earthworms had been added, whereas in the presence of earthworms, only 34% of the soybean residues remained. In the absence of earthworms, 85% of the maize residues were recovered at 36 days, compared with only 52% in the presence of earthworms. At 36 days, 48% of the original maize residues added were still > 2 mm in length in the absence of earthworms, whereas only 26% were > 2 mm in length in the presence of earthworms. Earthworms also increased the aggregate stability of the Raub soil, when determined on moist (19–22% w/w) samples, but had no effect on soil water retention at −33 and −1500 kPa. The possible implications of greater earthworm activity on increasing residue incorporation and breakdown and subsequent effects on soil temperatures under no-till maize production are also discussed.
Article
A new “direct extraction” method for measuring soil microbial biomass nitrogen (biomass N) is described. The new method (fumigation-extraction) is based on CHC13 fumigation, followed by immediate extraction with 0.5 M K2SO4 and measurement of total N released by CHC13 in the soil extracts. The amounts of NH4-N and total N extracted by K2SO4 immediately after fumigation increased with fumigation time up to 5 days. Total N released by CHC13 after 1 day fumigation (1 day CHC13-N) and after 5 days fumigation (5 day CHC13-N) were positively correlated with the flush of mineral N (FN) in 37 soils that had been fumigated, the fumigant removed and the soils incubated for 10 days (fumigation-incubation). The regression equations were 1 day CHC13-N = (0.79 ± 0.022) FN and 5 day CHC13-N = (1.01 ± 0.027) FN, both regressions accounting for 92% of the variance in the data.In field soils previously treated with 15N-labelled fertilizer, the amounts of labelled N, measured after fumigation-extraction, were very similar to the amounts of labelled N mineralized during fumigation-incubation; both were about 4 times as heavily labelled as the soil N as a whole. These results suggest that fumigation-extraction and fumigation-incubation both measure the same fraction of the soil organic N (probably the cytoplasmic component of the soil microbial biomass) and that measurement of the total N released by CHC13 fumigation for 24 h provides a rapid method for measuring biomass N.
Article
To investigate whether results of laboratory toxicity tests with earthworms are capable of being used to predict effects in the field, a literature study was carried out. Benomyl, its metabolite carbendazim, carbofuran, and carbaryl were chosen as model substances. From data on the behavior of these pesticides in soil, it can be concluded that shortly after application most of the dosage will be in the top 2.5-cm soil layer. Soil concentrations can be estimated from field dosages used. Estimated field soil concentrations that affected earthworm populations were in agreement with effect levels determined in laboratory studies. In the field, species living in the surface layers (e.g., juveniles of many species) or coming to the soil surface to feed (e.g., Lumbricus terrestris) are most affected, since they experience a high degree of exposure. Evidently, species having long generation times need a relatively long time to recover. Both the distribution of the pesticide and the behavior of earthworms in soil affect earthworm exposure. Insight into these aspects may provide tools to predict both short- and long-term effects of pesticides on earthworm populations in field soils.
Article
The persistence of the methylcarbamate pesticide carbaryl was studied in four soils under flooded conditions. A substantial portion of the pesticide was recovered from all soils even after 15 days of its application, with the recovery ranging from 37% in an alluvial soil to 73% in an acid sulfate soil. The degradation of carbaryl was more rapid under flooded conditions than under nonflooded conditions. A bacterium, Pseudomonas cepacia, isolated from a flooded soil amended with a related methylcarbamate pesticide carbofuran, degraded carbaryl in a mineral medium supplemented with yeast extract.
Nitrate and exchangeable ammonium nitrogen Soil Sampling and Methods of Ana-lysis
  • D G Maynard
  • Y P Kalra
Maynard, D.G., Kalra, Y.P., 1993. Nitrate and exchangeable ammonium nitrogen. In: Carter, M.R. (Ed.), Soil Sampling and Methods of Ana-lysis. Lewis Publishers, Boca Raton, FL, pp. 25–32.
National climate archive
  • Canada Environment
Environment Canada. National climate archive. http://climate.weatheroff ice.ec.gc.ca/ (Oct. 15th, 2005).
Biology and Ecology of Earthworms Consequences of earthworms in agricultural soils: aggregation and porosity
  • C A Edwards
  • P J M Bohlen
  • M J Shipitalo
Edwards, C.A., Bohlen, P.J., 1996. Biology and Ecology of Earthworms, third ed. Chapman & Hall, London, UK, p. 426. Edwards, W.M., Shipitalo, M.J., 1998. Consequences of earthworms in agricultural soils: aggregation and porosity. In: Edwards, C.A. (Ed.), Earthworm Ecology. CRC press, Boca Raton, FL, pp. 147–161.
The Earthworms (Lumbricidae and Sparganophili-dae) of Ontario Earthworm effects on crop and weed biomass, and N content in organic and inorganic fertilized agroecosystems
  • J W Reynolds
  • Institute
  • Nc Cary
  • B R Stinner
  • D A Mccartney
  • J M Blair
  • R W Parmelee
  • M F Allen
Reynolds, J.W., 1977. The Earthworms (Lumbricidae and Sparganophili-dae) of Ontario. Life Sciences Miscellaneous Publication, Royal Ontario Museum, Toronto. SAS Institute Inc., 2001. SAS procedures guide, Version 9.1, SAS Institute, Cary, NC. Stinner, B.R., McCartney, D.A., Blair, J.M., Parmelee, R.W., Allen, M.F., 1997. Earthworm effects on crop and weed biomass, and N content in organic and inorganic fertilized agroecosystems. Soil Biol. Biochem. 29, 423–426.
Consequences of earthworms in agricultural soils: aggregation and porosity
  • Edwards
Edwards, W.M., Shipitalo, M.J., 1998. Consequences of earthworms in agricultural soils: aggregation and porosity. In: Edwards, C.A. (Ed.), Earthworm Ecology. CRC press, Boca Raton, FL, pp. 147-161.