Earthworm activity and its coupling to soil hydrology: A deterministic analysis

The Salix genus includes shrub species that are widely used in phytoremediation and various other phytotechnologies due to their advantageous characteristics, such as a high evapotranspiration (ET) rate, in particular when cultivated in short rotation intensive culture (SRIC). Observations made in past field studies suggest that ET and its impact on soil hydrology can also lead to increases in soil pollutant concentrations near shrubs. To investigate this, sections of a mature willow plantation (seven years old) were cut to eliminate transpiration (Cut treatment). Soil concentrations of polychlorinated biphenyls (PCBs), aliphatic compounds C10–C50, polycyclic aromatic hydrocarbons (PAHs) and five trace elements (Cd, Cr, Cu, Ni and Zn) were compared between the Cut and the uncut plots (Salix miyabeana ‘SX61’). Over 24 months, the results clearly show that removal of the willow shrubs limited the contaminants’ increase in the soil surface, as observed for C10–C50 and of 10 PAHs under the Salix treatment. This finding strongly reinforces a hypothesis that SRIC of willows may facilitate the migration of contaminants towards their roots, thus increasing their concentration in the surrounding soil. Such a “pumping effect” in a high-density willow crop is a prominent characteristic specific to field studies that can lead to counterintuitive results. Although apparent increases of contaminant concentrations contradict the purification benefits usually pursued in phytoremediation, the possibility of active phytoextraction and rhizodegradation is not excluded. Moreover, increases of pollutant concentrations under shrubs following migration suggest that decreases would consequently occur at the source points. Some reflections on interpreting field work results are provided.

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Statistical and deterministic analysis of covid-19 spread in Saudi Arabia

Results in Physics ◽

10.1016/j.rinp.2021.104578 ◽

2021 ◽

pp. 104578

Author(s):

Naif Alotaibi

Keyword(s):

Saudi Arabia ◽

Deterministic Analysis

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Earthworm Inoculation Improves Upland Rice Crop Yield and Other Agrosystem Services in Madagascar

Agriculture ◽

10.3390/agriculture11010060 ◽

2021 ◽

Vol 11 (1) ◽

pp. 60

Author(s):

Onja Ratsiatosika ◽

Malalatiana Razafindrakoto ◽

Tantely Razafimbelo ◽

Michel Rabenarivo ◽

Thierry Becquer ◽

...

Keyword(s):

Upland Rice ◽

Cropping Systems ◽

Conservation Agriculture ◽

Biological Properties ◽

Rice Grain ◽

Positive Effects ◽

Ecological Transition ◽

Earthworm Activity ◽

Endogeic Earthworms ◽

Plant Properties

The effects of earthworm inoculation and cropping systems on upland rice systems were examined over a four-year period in the Highlands of Madagascar. Each year, endogeic earthworms Pontoscolex corethrurus (Rhinodrilidae) were inoculated (EW+) at a density of 75 ind m−2 or were not inoculated (EW0). Inoculation was tested in three cropping systems: conservation agriculture (CA) and traditional tillage with or without residues restitution. Soil and plant properties were measured during the first three years while soil biological properties were assessed at the fourth year. At the end of the experiment, earthworm density was three-fold higher in EW+ than in EW0, demonstrating the success of the inoculation. Earthworm density was more important in CA than in tillage systems. Earthworm inoculation had higher significant effects on soil and plant properties than cropping systems. Earthworm inoculation had positive effects on soil macroaggregation (+43%), aboveground biomass (+27%), rice grain yield (+45%), and N grain amount (+43%). Intensifying earthworm activity in field conditions to meet the challenge of ecological transition is supported by our study.

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Global earthworm distribution and activity windows based on soil hydromechanical constraints

Communications Biology ◽

10.1038/s42003-021-02139-5 ◽

2021 ◽

Vol 4 (1) ◽

Author(s):

Siul A. Ruiz ◽

Samuel Bickel ◽

Dani Or

Keyword(s):

Soil Structure ◽

Mechanistic Model ◽

Biophysical Model ◽

Ecosystem Functions ◽

Soil Conditions ◽

Agricultural Systems ◽

Occurrence Patterns ◽

Additional Constraints ◽

Earthworm Activity ◽

Good Agreement

AbstractEarthworm activity modifies soil structure and promotes important hydrological ecosystem functions for agricultural systems. Earthworms use their flexible hydroskeleton to burrow and expand biopores. Hence, their activity is constrained by soil hydromechanical conditions that permit deformation at earthworm’s maximal hydroskeletal pressure (≈200kPa). A mechanistic biophysical model is developed here to link the biomechanical limits of earthworm burrowing with soil moisture and texture to predict soil conditions that permit bioturbation across biomes. We include additional constraints that exclude earthworm activity such as freezing temperatures, low soil pH, and high sand content to develop the first predictive global map of earthworm habitats in good agreement with observed earthworm occurrence patterns. Earthworm activity is strongly constrained by seasonal dynamics that vary across latitudes largely due to soil hydromechanical status. The mechanistic model delineates the potential for earthworm migration via connectivity of hospitable sites and highlights regions sensitive to climate.

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The effect of earthworm activity on soil bioporosity – Investigated with X-ray computed tomography and endoscopy

Soil and Tillage Research ◽

10.1016/j.still.2014.05.007 ◽

2015 ◽

Vol 146 ◽

pp. 79-88 ◽

Cited By ~ 35

Author(s):

Sebastian K. Pagenkemper ◽

Miriam Athmann ◽

Daniel Uteau ◽

Timo Kautz ◽

Stephan Peth ◽

...

Keyword(s):

Computed Tomography ◽

X Ray ◽

X Ray Computed ◽

Earthworm Activity

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A numerical model for the deterministic analysis of adhesive rough contacts down to the nano-scale

International Journal of Solids and Structures ◽

10.1016/j.ijsolstr.2014.03.033 ◽

2014 ◽

Vol 51 (14) ◽

pp. 2620-2632 ◽

Cited By ~ 43

Author(s):

Simon Medina ◽

Daniele Dini

Keyword(s):

Numerical Model ◽

Deterministic Analysis ◽

Nano Scale

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Seasonal activity and estivation of lumbricid earthworms in the midlands of Tasmania

Soil Research ◽

10.1071/sr9941355 ◽

1994 ◽

Vol 32 (6) ◽

pp. 1355 ◽

Cited By ~ 12

Author(s):

RB Garnsey

Keyword(s):

Soil Moisture ◽

Adult Development ◽

Survival Rates ◽

Soil Surface ◽

Early Spring ◽

Lumbricus Rubellus ◽

Late Winter ◽

Cocoon Production ◽

Density And Biomass ◽

Earthworm Activity

Earthworms have the ability to alleviate many soil degradational problems in Australia. An attempt to optimize this resource requires fundamental understanding of earthworm ecology. This study reports the seasonal changes in earthworm populations in the Midlands of Tasmania (<600 mm rainfall p.a.), and examines, for the first time in Australia, the behaviour and survival rates of aestivating earthworms. Earthworms were sampled from 14 permanent pastures in the Midlands from May 1992 to February 1994. Earthworm activity was significantly correlated with soil moisture; maximum earthworm activity in the surface soil was evident during the wetter months of winter and early spring, followed by aestivation in the surface and subsoils during the drier summer months. The two most abundant earthworm species found in the Midlands were Aporrectodea caliginosa (maximum of 174.8 m-2 or 55.06 g m-2) and A. trapezoides (86 m-2 or 52.03 g m-2), with low numbers of Octolasion cyaneum, Lumbricus rubellus and A. rosea. The phenology of A. caliginosa relating to rainfall contrasted with that of A. trapezoides in this study. A caliginosa was particularly dependent upon rainfall in the Midlands: population density, cocoon production and adult development of A. caliginosa were reduced as rainfall reduced from 600 to 425 mm p.a. In contrast, the density and biomass of A. trapezoides were unaffected by rainfall over the same range: cocoon production and adult development continued regardless of rainfall. The depth of earthworm aestivation during the summers of 1992-94 was similar in each year. Most individuals were in aestivation at a depth of 150-200 mm, regardless of species, soil moisture or texture. Smaller aestivating individuals were located nearer the soil surface, as was shown by an increase in mean mass of aestivating individuals with depth. There was a high mortality associated with summer aestivation of up to 60% for juvenile, and 63% for adult earthworms in 1993 in the Midlands. Cocoons did not survive during the summers of 1992 or 1994, but were recovered in 1993, possibly due to the influence of rainfall during late winter and early spring.

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Effects of glyphosate-based herbicides and their active ingredients on earthworms, water infiltration and glyphosate leaching are influenced by soil properties

Environmental Sciences Europe ◽

10.1186/s12302-021-00492-0 ◽

2021 ◽

Vol 33 (1) ◽

Author(s):

Johann G. Zaller ◽

Maureen Weber ◽

Michael Maderthaner ◽

Edith Gruber ◽

Eszter Takács ◽

...

Keyword(s):

Organic Matter ◽

Soil Properties ◽

Weed Control ◽

Amaranthus Retroflexus ◽

Water Infiltration ◽

Soil Conditions ◽

Soil Functions ◽

Active Ingredients ◽

Hand Weeding ◽

Earthworm Activity

Abstract Background Glyphosate-based herbicides (GBHs) are among the most often used pesticides. The hundreds of GBHs used worldwide consist of the active ingredient (AI) glyphosate in form of different salts, possibly other AIs, and various mostly undisclosed co-formulants. Pesticide risk assessments are commonly performed using single AIs or GBHs at standard soil conditions without vegetation. In a greenhouse experiment, we established a weed population with common amaranth (Amaranthus retroflexus) to examine the effects of three GBHs (Roundup LB Plus, Roundup PowerFlex, Touchdown Quattro) and their corresponding AIs (salts of glyphosate isopropylammonium, potassium, diammonium) on the activity and physiological biomarkers (glutathione S-transferase, GST; acetylcholine esterase, AChE) of an ecologically relevant earthworm species (Lumbricus terrestris). GBHs and AIs were applied at recommended doses; hand weeding served as control. Experiments were established with two soil types differing in organic matter content (SOM; 3.0% vs. 4.1%) and other properties. Results Earthworm activity (casting and movement activity) decreased after application of glyphosate formulations or active ingredients compared to hand weeding. We found no consistent pattern that formulations had either higher or lower effects on earthworm activity than their active ingredients; rather, differences were substance-specific. Earthworm activity was little affected by soil organic matter levels. Biomarkers remained unaffected by weed control types; GST but not AChE was decreased under high SOM. Water infiltration after a simulated heavy rainfall was interactively affected by weed control types and SOM. Leachate amount was higher after application of formulations than active ingredients and was higher under low SOM. Glyphosate concentrations in soil and leachate were strongly affected by application of formulations or active ingredients and varied with SOM (significant weed control type x SOM interaction). Conclusions We found that both commercial formulations and pure active ingredients can influence earthworms with consequences on important soil functions. Glyphosate products showed increased, reduced or similar effects than pure glyphosate on particular soil functions; soil properties can substantially alter this. Especially at lower SOM, heavy rainfalls could lead to more glyphosate leaching into water bodies. A full disclosure of co-formulants would be necessary to further decipher their specific contributions to these inconsistent effects.

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