Technical guide

2022 | No. 1629

Earthworms – architects of fertile soils

Their significance and recommendations for their promotion
in agriculture
 Earthworms are usually the most abundant soil Underestimated soil workers
animals in agricultural soils. They are known to
improve physical, chemical and biological pro­ In the 19th century, earthworms were considered
perties of soils. Together with soil microorga­nisms a soil pest. Even though this view has completely
they have a great potential to enhance soil fer­ changed, they still don’t receive sufficient attention
tility. in agricultural practice. Few farmers actively pro­
Although much is known about the general mote them. Instead, heavy machines, intensive till­
taxo­nomy and biology of earthworms, know­ age and wide use of pesticides have in many places
ledge about their impact on soils, their interac­ eliminated or drastically reduced earthworm popu­
tions with other soil organisms and the influence lations. In contrast, in a naturally managed grass­
of farming practices on their populations is in­ land soil of one hectare up to three million earth­
creasing only slowly. worms can be found.
This guide summarises the knowledge on Number, biomass and diversity of earthworms
earthworms. It gives an overview of the biology, in a soil are considered an important criterion of soil
ecology and the multiple services of earthworms fertility, as a rich earthworm fauna contributes in
to agriculture, and provides recommendations for many ways to healthy and biologically active soils,
the promotion of these extraordinary organisms which again favour many positive ecosystem ser­
in agricultural soils. vices and involve a better resilience and adaptation
of farming systems to climate change. Due to their
numerous contributions to increase sustainability of
agro-ecosystems, earth­worms should receive more
attention and be specifically promoted in sustaina­
ble farming – and especially in organic farming.

Content
Underestimated soil workers 2
Distribution and biology of earthworms 3
Services of earthworms for agriculture 4
Ecological groups of earthworm species 6
Estimation of the number of earthworms in a soil 8
Effective agricultural practices to enhance
earthworms 8
Negative impact of non-organic agricultural
practices on earthworm populations 12

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Distribution and biology of earthworms
Distribution Feeding
With the exception of polar regions and deserts, Earthworms primarily feed on dead plant parts but
earth­worms (Lumbricina) can be found in most soils. don’t have the digestive enzymes to break down the
While more than 3.000 species are known world­ cellular structure of plant materials. Therefore, they
wide, only 400 species are found in Europe and mix plant biomass with mineral soil for digestion.
40 species in Central Europe. In crop­land, only 4 to To meet their daily calorie needs, they have to eat
11 species are commonly found. 10 to 30 times their own body weight.
At night, they graze on the lawns of algae that
Soils have grown on the soil surface during the day and
Earthworms prefer medium-heavy loam to loamy pull dead plant parts into their burrows for ‘pre-
sand soils. Heavy clay and dry sandy soils are not diges­tion’ by soil microorganisms in 2 to 4 weeks.
favourable to their development and limit their As earthworms do not have teeth, they cannot feed
spreading. In acidic peat soils, only specialised on roots. In order to thrive, earthworms require a
species are found that have adapted to such unfa­ rich food supply of plant debris such as dead roots,
vourable soil conditions. leaves, grasses and organic manure.

Climate
Earthworms cannot regulate the body temperature
themselves. Therefore, when it is very dry and hot,
many earthworms estivate and retreat to deeper soil
layers. With low winter temperatures, the worms
retreat to frost-free portions of their burrows, and
their metabolism slows down to the minimum. Dur­
ing frost-free winter days, they become active again.
In spring and autumn, earthworms are most active.
Earthworms are intolerant to drought. They are
active only when the soil is moist, and are inactive
when it is dry. As earthworms can lose up to 20 % of An earthworm emerges from a cocoon.
their body weight each day in mucus and castings,
they need moisture to stay alive.

Development
Earthworms develop slowly, with the exception of
the leaf litter dwellers (e. g. compost worms). They
produce only one generation with a maximum of 8
to 12 cocoons (eggs) per year. Earthworms live 2 to
10 years, depending on the species.

Reproduction A Nicodrilus sp. curls up to survive cold, hot or drought periods

Earthworms are hermaphrodites. Sexually mature and during hibernation or estivation.
worms can be identified by the ‘genital belt’ (clitel­
lum) encircling the body. Peak burrowing activity
and reproduction in the temperate zone take place
in March and April and also in September and Oc­
tober.

Mobility
Earthworms can migrate into cropland from un­
disturbed edge areas like field margins. The night
crawler (Lumbricus terrestris) can migrate as far as
20 metres per year. Birds and livestock contribute Only mature specimen with a clitellum can be clearly determined
significantly to the dispersal of earthworms. to a species level (e.g. Eisenia foetida).

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 Services of earthworms for agriculture
Earthworms affect many ecoservices that relate to soil properties by earthworms entails numerous
soil fertility and plant production. Hence, the pro­ benefits for farmers such as an increase of nutrient
motion of earthworms and other critical soil bio­ availa­bility and water storage in soils, reduced ero­
ta helps making more efficient use of ecological sion, and improved farm productivity.
processes. The improvement of abiotic and biotic

More organic matter Better soil structure Better water infiltration

Less soil distubance More earthworms & microbes Better water storage
More carbon in the soil Less soil erosion
Increased climate resilience

Earthworms play a key role in improving soil properties. The benefits resulting from their activity are diverse. However, they depend on
­sufficient organic matter and low soil disturbance to perform their tasks.

1. Earthworms aerate the soil 2. Earthworms facilitate root growth

Earthworm burrows increase the amount of mac­ Over 90 % of the burrows tend to be colonised by
ropores and thus contribute to a good aeration of plant roots. Earthworms leave a major part of their
the soil. nutrient-rich casts in their burrows. This provides
a favourable environment for the growth of plant
roots. Thanks to the burrows, plant roots can more
easily penetrate into deeper soil layers, finding nu­
trient-rich earthworm casts, water and air. Earth­
worm burrows also help incorporate surface ap­
plied lime and fertiliser into the soil.

3. Earthworms improve water infiltration

into soils and reduce surface runoff
The stable burrows of the vertical burrowers, in par­
ticular, considerably improve water infiltration, stor­
age and drainage of soils. Surface runoff and erosion
are thus reduced. Soils with earthworms drain up to
10 times faster than soils without earth­worms.
The vertical burrows, stabilised with slime,
can be as deep as 3 metres in deep loess soils, and
even as deep as 6 metres in chernozem soils (i. e.
black earths). Due to their powerful muscles, deep
The burrows made by deep-burrowing earthworms make it easier burrowers are able to penetrate slightly compacted
for roots to penetrate deep into the soil. soils and thus improve drainage.

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Up to 150 burrows – or 900 metres of burrows per
square metre and metre of depth – can be found
in unploughed soil. In zero-till soils, where worm
populations are high, water infiltration can be up to
6 times greater than in cultivated soils.

4. Earthworms incorporate dead plant

matter into the soil
Earthworms incorporate organic material such
as crop residues, organic manure, dung or mulch
into the soil. They fragment, mix and digest plant
debris through physical grinding and chemical di­ This soil has many worm casts on the surface indicating high ­earth­worm activity.
gestion. This accelerates the decomposition of the It hardly becomes muddy after heavy rains. ­Picture taken at the same time as the photo
on right side from an organically managed plot of the DOK ­long-term trial in Therwil,
dead plant matter and thus stimulates the nutrient
Switzerland.
cycling in the soil-plant system. When earthworms
draw down plant materials into the burrows, they
relocate valuable nutrients throughout the soil, es­
pecially to the deeper soil layers.
Under grassland conditions, earthworms in­
corporate up to 6 tons of dead organic matter per
hectare per year into the soil. In forests, earthworms
process as much as 9 tons of foliage per hectare.

5. Earthworms decompose dead plant

matter and increase plant nutrients
Earthworms produce 40 to 100 tons of casts per hec­
tare annually. The worm casts form stable soil ag­
gregates or crumbs, which are deposited on the soil Earthworm casts are largely lacking on this soil surface, indicating little earthworm
surface or in the soil. Organic and inorganic frac­ activity. During heavy rains, the soil surface tends to silt up. Picture taken from a conven-
tionally managed plot of the DOK long-term trial in Therwil, Switzerland.
tions are well-mixed in worm casts, and the nutri­
ents are present in a readily available and enriched
form. The casts contain on average 5 times more
nitrogen, 7 times more phosphorus, and 11 times
more potassium as the surrounding soil. The nitro­
gen in the casts is readily available to plants.

6. Earthworms rejuvenate the soil

Earthworms transport soil material and nutrients
from the subsoil to the topsoil and thus maintain
respectively foster the vitality of the soil.

7. Earthworms help improve soil structure

and soil stability
By the intensive mixing of organic matter with
inorganic soil particles and microorganisms and
by slime secretion, earthworms create stable soil
crumbs, which enhance soil structure. Soils with
high earth­worm activity have less tendency to be­
come muddy and can be worked more easily than
soils with low earthworm activity. In addition, nu­
trients and water are more effectively retained in
the soil. Abundant worm casts production makes With a good food supply, a high earth­worm population can deposit annually up to 10 kg
heavy soils looser and sandy soils more cohesive. per square metre of valuable worm droppings in the soil and on its surface. This makes as
much as 0.5 cm of the soil layer in fields, and as much as 1.5 cm in meadows.

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 8. Earthworms act as biocontrol
propagators
Earthworms promote the colonisation and propa­
gation of beneficial soil bacteria and fungi in their
burrows and casts. By pulling fallen leaves into the
soil, foliar pathogens and pests – i. e. winter stages
of fungal pathogens such as apple scab, and insects
such as leaf miners – are biologically degraded.
Soils with high earthworm activity provide ideal growing ­conditions
9. Earthworms help control soil-borne for crops.
pests
Scientific studies show that earthworms promote
the growth and propagation of beneficial organ­ 10. Earthworms support carbon
isms in the soil. Earthworms distribute insect-kill­ sequestration
ing nematodes (e.g. Steinernema sp.) and fungi (e.g. Earthworms ingest organic residues of different
Beauveria bassiana) in the soil, thus contributing C : N ratios and convert it to a lower C : N ratio and
to a better natural regulation of soil-borne pests. finally contribute to carbon sequestration. By doing
Dormant forms, like fungus spores, however, resist so, they help mitigate climate change.
digestion in the earthworm gut and are excreted
in casts.

Ecological groups of earthworm species

Earthworms are classified into three main eco-phy­ Surface-dwelling earthworm species (epigaeic spe­
siological categories (see also Table 1, page 7): cies) are of particular importance for the decomposi­
1) Leaf litter- or compost-dwelling worms: they tion of litter material and in composting (see Box 1).
are nonburrowing and live at the soil-litter
interface and eat decomposing organic matter.
These worms are epigeic species. Box 1: Critical role of epigeic worm
2) Subsoil-dwelling worms: they feed (on soil), species in vermicomposting
burrow and cast within the soil, creating hori­ Vermicomposting is a process using various epi-
zontal burrows in the upper 10–30 cm of the geic worm species to decompose organic waste
soil. These earthworms are endogeic species. and produce a nutrient-rich organic fertiliser and
3) Top-soil dwelling earthworms that construct soil conditioner for small-scale farming. The quali-
permanent deep vertical burrows: they use ties of the vermicompost are essentially due to the
the burrows to visit the soil surface to obtain high nutrient content of the earthworm casts.
plant material for food (anectic species).

In agriculture, vertical burrowers play a key role

(higher biomass and bioturbation, permanent bur­
rows, water infiltration into the soil). For arable and
forage production, all burrowing worm species (i. e.
endogeic and anectic species) play an important role.
Shallow burrowing worms contribute to improving
soil fertility and structure in the topsoil, whereas
the vertical burrowing earthworms contribute to
noticeable soil improvements in deeper soil layers
by bringing organic matter into deeper layers and Epigeic worm types are the basis in vermicomposting.
improving soil aeration and water retention with The technology is broadly used in small-scale organic farming to
produce a high-quality soil amendment from crop residues and
their vertical tunnels. Latter also promote deeper
organic wastes. Compost-dwelling (e.g. Eisenia sp.) earthworms do
rooting of arable soils, which tends to lead to higher not survive on arable land or in other cropping systems.
yields as more nutrients are available.

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Table 1: Three ecological earthworm groups in temperate ecosystems

Groups Leaf litter dwellers Shallow burrowers Deep burrowers

Types/Species Surface dwellers/ Shallow and horizontal Vertically burrowers/
epigeic species burrowers/endogeic species anectic species

Important • Redworm (Eisenia fetida) • Octolasion lacteum • Nightcrawler (L. terrestis)

representatives • European earthworm • Common field worm • Black-headed worm
(Lumbricus rubellus) (Allolobophora caliginosa) (Allolobophora longa)
Pigmentation Heavy, brownish-red, usually Un- or lightly pigmented Medium, reddish-brown, head
both ventrally and dorsally darker, usually only dorsally
Habitat • In litter layers, especially • Topsoil (5–40 cm) of humic • All soil layers, 3–4 m deep
in grasslands, forests, mineral soil • Entire life in vertical, stable
and compost • In mostly horizontal, unstable dwelling tubes (Ø 8–11 mm)
• Rarely in cropland due to lack burrows • Very important in agricultural
of permanent litter layers • Juveniles in upper layers soils
Size Small, generally 2–6 cm long Small, up to 18 cm long Generally large, 15–45 cm long
Burrowing capac. Low Moderate High
Feeding • Feed on small plant parts on • Feed on plant parts • Pull large plant parts into
behaviour the surface of the soil. ­incorporated in the topsoil. their dwelling tubes.
Survival during • In cocoon stage • Quiescence during drought • Quiescence during drought
drought and • Diapause for hibernation • Partial or no diapause during
in winter winter (L. terrestris)
Predation • Very high (birds, mammals • Low • High, if crawling on the soil
and predatory arthropods) surface
Reproduction • Vigorous (100 cocoons p. a.) • Limited (8–12 cocoons p. a.) • Limited (8–12 cocoons p. a.)
Lifespan • Short, 1–2 years • Medium, 3–5 years • Long, 4–8 years

Figure 1: Feeding and living habits of the three ecological groups of earthworms

Leaf litter dwellers

Epigeic species
cm
Cast
0

5 Earthworm burrow
Shallow burrowers Cast lining
10 Endogeic species Root
Soil
Topsoil

15
Burrows Partially filled with Vertical burrowers
20 casts Anecic species

25 Plough pan = compacted zone

30 The three groups of earth­worms

have distinctly different feeding
Old dwelling burrow and living habits.
Bottomsoil

400

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 Estimation of the number of earthworms in a soil
Earthworm numbers vary widely in different soils
depending on soil type, rainfall and farming prac­
tices. In arable soils, their number may range from
30 to 300 individuals per square metre. In Central
Europe, 120 to 140 worms per square metre make a
good population density for intensively cultivated
cropland. This corresponds to 90 to 110 g of earth­
worm biomass per square metre.
As a means to easily assess the earthworm
popu­lation in a certain field, the approximate num­
ber of worms can be roughly estimated using the
following methods: The number of earthworms can be easily assessed with the spade
• Number of worms: 5 samples of 10 × 10 cm and diagnosis.
25 cm deep spade full of fertile, medium-heavy
loam soil contains in average 2 to 3 worms. This
amount corresponds to 100 to 200 worms per Box 2: Habitat related earthworm
square metre. density
• The number of worm burrows is also a good The colonisation of a habitat by earthworms
indicator of worm activity in the soil. primarily depends upon food and water supply.
• When counting the number of casts (worm Accordingly, there is considerable variation in
droppings) on a 50 × 50 cm area during the the number of earthworms per square metre:
pe­riods of earthworm activity (March to April Low-input pasture 400–500 earthworms
and September to October), 5 or fewer casts Fertilised meadow 200–300 earthworms
indicate little worm activity, 10 casts indicate Hardwood forest 150–250 earthworms
moderate worm activity, whereas 20 or more Low-input arable field 120–250 earthworms
casts indicate good worm activity with the soil Poor grassland 30–40 earthworms
containing many worms. Spruce forest 10–15 earthworms

Effective agricultural practices to enhance earthworms

Earthworm populations tend to increase with high­
er soil organic matter levels and decrease with in­
tensive soil disturbances, such as tillage and the use
of harmful chemicals. Implementation of appropri­
ate measures can decisively promote earth­worms
and in a broader sense soil fertility. Thus, it is key
to understand what measures spare or promote
earthworms.

Avoiding intensive soil tillage and

minimising the use of the plough
• Ploughs and fast-rotating devices can greatly
damage earthworms. Loss rates of earthworms Intensive soil tillage should be avoided during the periods of high
after the use of ploughs are about 25 %, and earthworm activity in March/April and September/October.

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 Figure 2: Impact of different intensities of tillage on earthworms
Intensive soil tillage Medium-intensive soil tillage
Up to about 70% earthworm losses Up to about 25% earthworm losses
Leaf litter dwellers
cm cm
0 0
Moderate damage of
5 5
the habitat
Spring/autumn:
Horizontal burrowers vertical burrowers Horizontal burrowers
10 in the topsoil 10
Tractor-drawn equipment
15 15
Rotary Severe damage
20 equipment of the habitat 20

25 25 Compacted zone by plough

30 30

Vertical burrowers Summer/winter:

vertical burrowers in the subsoil

The more intensively the soil is cultivated, the greater are the losses of earthworms. Losses are highest in spring and autumn.

can be as high as 70 % with the use of rotary • Conservation tillage, which includes reduced
devi­ces. Therefore, ploughs and fast-rotating tillage, minimises soil disturbance, lowers the
devices should only be used if absolutely neces­ risk of soil compaction, increases food supply,
sary and when earthworms are less active in the and conserves soil water. These enhance the
topsoil. density and biomass of earthworms (as well as
• Tillage of dry or cold soils has much lower of soil microorganisms in general).
negative impacts on earthworm populations, as
the majority of the earthworms have retreated
to lower soil layers during such periods. Figure 3: Impact of reduced tillage on
• The use of on-land ploughs and shallow plough­ earthworms compared to ploughing
ing reduces compaction of deeper soil layers.
Total biomass + 48 %

Total earthworm density + 67 %

Adult density + 39 %

Juvenile density + 82 %

Cocoons + 438 %

100 125 150 175 200 400 425 450 475

Increase with reduced tillage in %
Conventional tillage = 100 %

With conventional inversion tillage, earthworms are injured and killed directly.
Reduced tillage minimises soil disturbance and maximises soil More­over, they become exposed to harsh environmental conditions and predators and,
cover from both mulched crop residues and living green in the case of anectic species (vertical burrowers), their burrows are destroyed and
manures, creating favourable living conditions for earthworms. their food sources buried. As the numbers above indicate, reduced tillage results in a
significant increase of earthworm population density, biomass and growth stages
compared to ploughing, according to the results from an organically managed clay soil
(Kuntz et al. 2013).

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 Minimising ground pressure Diversifying crop rotation to
and soil compaction provide food for earthworms
Earthworms need reasonably aerated and ‘loose’ Diversified crop rotations with a good soil cover
soil. Compaction of the soil has negative implica­ and a regular supply of organic matter provide fa­
tions on earthworm populations, other soil organ­ vourable living conditions for earthworms.
isms, and biological processes in the soil, in general.
Earth­worms have difficulty to dig through heavily What to consider
compacted soil. Therefore, soil compaction should • Permanent grassland is ideal for earthworms.
be avoided or at least minimised. It provides high amounts of organic matter
from leaves and roots. Pasture slashings and
What to consider decomposed manure from grazing animals are
• Adapt agricultural machinery to keep ground also good sources of organic matter.
pressure to a minimum, reducing especially • Diversified crop rotations with long-lasting and
tyre pressure. deep-rooted catch crops (rich in clover) or green
• Where possible, use light weight m ­ achinery. manure crops, and diversified crop residues
The lighter the equipment, the lower the are the basis for a good earthworm population.
­compaction of the soil. Rota­ting grassland/grass-clover meadows with
• As wet soils are especially sensitive to soil annual crops helps build up organic matter
­compaction, cultivate only well-dried, good levels and promotes the earthworm fauna.
bearing soils. • Green manures are cultivated for high biomass
• Drain or mound arable soils that tend to production and turned into the soil at maxi­
­waterlogging. mum biomass stage to provide organic matter
to benefit the subsequent crop. Crops can also
be grazed or slashed and then left on the surface
for decomposition.
• Crop stubble is an important source of organic
matter. Burning stubble destroys the organic
matter in the top soil layers, which affects earth­
worm at the surface. Ideally, the stubble is left
to rot on the soil surface and the following crop
is sown directly into the stubble (tricky with
organic) or after minimal tillage.
• Groundcover such as grassland/grass-clover
meadows or stubble reduce soil moisture evap­
oration, thus keeping the soil moist. Organic
matter cover also helps reduce the effect of
The on-land plough prevents soil compaction in the plough pan. climatic extremes, i. e. as heat and frost.
• As soil humus holds moisture in the soil, an
increased soil organic matter content not only
contributes to a better water supply for crops
during drought, but also to more balanced
living conditions for earthworms.
• 2-year grass-clover meadows within a crop
rotation regenerate earth­worm populations
substantially. Multi-annual grass-clover is more
beneficial than a 1-year grass ley.

The residues of green manures and cover crops conserve soil

­moisture and provide food for earthworms.

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Appropriate fertilising according
to soil properties and plant needs
Both the type and the amount of fertiliser that are
used affect earthworm populations.

What to consider
• An adequate and well-balanced fertilisation
is favourable for both the crops and the earth­
worms. Liquid manures are beneficial for both earthworms and crops when diluted and
• Slightly-rotted composted manure contains applied in moderate amounts at an appropriate time of crop growth and during cool
and cloudy weather conditions.
more food for earthworms and, thus, is b ­ etter
suited to promote earthworms than ripe
­compost.
• Organic fertilisers should only be incorporated Box 3: Key measures for the promotion
to a shallow depth. Deeply buried crop residues of earthworms
are detrimental to earthworms as they can cre­ The following measures are pre-requisites for the
ate anaerobic conditions during decomposition. flourishing of earthworms in agricultural soils:
• Since ammonia in unprocessed liquid manure 1. Provision of sufficient plant material to earth-
is toxic for many organisms and thus very worms on arable land with permanent ground
harmful especially to earthworms living near cover also during winter
the surface in waterlogged soils, liquid manures 2. Abstaining from the use of pesticides that are
should be stirred (and thus aerated) and diluted harmful to earthworms and other beneficial
prior to their application. organisms
• Liquid manures should be applied to absorbent 3. Implementation of gentle soil cultivation
soils only and in moderate amounts of not more methods such as reduced tillage and no-till to
than 25 m3 per hectare. promote soil fertility
• Most earthworms prefer a soil pH of 5.5 to 7.5. 4. Avoidance of soil compaction and promotion
To ensure an optimal soil pH, lime should be of well-structured and aerated soils using
applied routinely on the basis of pH measure­ adapted machinery
ments. 5. Site and crop appropriate fertilisation
6. Continuous supply of fresh and dry organic
matter throughout the crop rotation

Organic fertilisation promotes a rich earthworm fauna that improves soil structure, thus cutting down silting up, and that improves infiltration
and storage of water. Picture left: conventionally managed plot of the DOK long-term trial in Therwil, Switzerland. Picture right: organically
managed plot from the same trial. Both pictures were taken after the same rain incidence.

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 Negative impact of non-organic agricultural practices
on earthworm populations

Use of harmful pesticides agents). Yet, they tend to indirectly reduce earth­
worm populations by decreasing the availability of
Various pesticides (including seed coating) can in­ organic matter on the soil surface as they inhibit
crease individual mortality, decrease fecundity and the growth of weed plants. Especially in crops and
growth, and disrupt enzymatic processes. Moreo­ rotations with no or little ground coverage, weeds
ver, they can change individual behaviour of earth­ are an important feed source for earthworms.
worms reducing for example their feeding rate and
finally decreasing their overall community biomass Use of mineral fertilisers
and density. Shallow dwellers (i. e. endogeic species
such as A. caliginosa) on arable land, which contin­ Most synthetic mineral fertilisers may not harm
uously extend their burrows as they feed in the sub­ earthworms directly. However, ammonium sul­
surface soil, are most susceptible to toxic pesticides phate-based fertilisers can be harmful to earth­
incorporated into the soil. In contrast, earthworm worms, possibly due to an acidifying affect. Fur­
species that live in deeper layers (i. e. anectic earth­ thermore, the use of high levels of mineral nitrogen
worms such as Lumbricus terrestris) are less suscep­ fertilisers (not allowed in organic farming) may re­
tible to surface application of pesticides. duce earthworms and competes with the cultivation
Insecticides and fungicides are the most toxic of leguminous cover crops and green manures to
pesticides impacting survival and reproduction, re­ increase the availability of nitrogen in soils, the lat­
spectively. Some fungicides, such as Bordeaux mix­ ter being crops that are highly beneficial for earth­
ture or other copper sprays (also allowed in organ­ worms. Lime seems to be beneficial to earthworm
ic farming) reduce earthworm numbers in the soil populations. In general, organic fertilisers (inclu­
when applied in high amounts, such as commonly ding aerated slurry) have a far more positive impact
done in orchards and vineyards. on earthworms than mineral fertilisers.
In general, most herbicides do not harm earth­
worms directly, if they are applied at recommended
rates of use (with exception of synthetic burn-off
Imprint
Published by:
Research Institute of Organic Agriculture FiBL
Figure 4: Effect of mineral and organic Ackerstrasse 113, P.O.Box 219, 5070 Frick, Switzerland
Phone +41 (0)62 865 72 72, info.suisse@fibl.org, www.fibl.org
fertilisation on earthworms
Author: Lukas Pfiffner (FiBL)
200 % Review of the first edition: Josephine Peigné (ISARA, Lyon),
Paul Mäder (FiBL) and Julia Cooper (Newcastle University, UK)
180 %
Editing: Gilles Weidmann and Thomas Bernet (FiBL)
160 %
Design: Brigitta Maurer (FiBL)
140 % Photo credits: Thomas Alföldi (FiBL): page 1, 4 (1, 2), 5 (1, 2), 6 (1), 8,
9, 10, 11 (1); Monica Biondo (Pro Natura): p. 3 (2); Gabriela Brändle
120 % (Agroscope): p. 4 (3); Otto Ehrmann (D-Creglingen): p. 4 (4), 5 (3);
Conventional = 100 % Andreas Fliessbach (FiBL): p. 11 (2, 3); Jacques Fuchs (FiBL): p. 6 (2);
100 % Earthworm
individuals Fritz Häni (SHL Zollikofen): p. 3 (1); Lukas Pfiffner (FiBL): p. 3 (3), 7;
80 % (Conv. = René Schulte (Bio Suisse): p. 2
247 individuals DOI: 10.5281/zenodo.6670157 FiBL No. 1629
60 % per m2)
This guide is available for free download at shop.fibl.org
40 % Earthworm
biomass All information contained in this guide was produced by the author to the
20 % (Conv. = 183 g best of his knowledge, and checked by him and the editor with the utmost
per m2) care. However, errors cannot be completely ruled out. Never­theless, mis-
0% takes cannot be ruled out entirely. This is why all information etc. comes
Mineral fertilisation Organic fertilisation without any obligation or guarantee of the author or editor. Both therefore
do not assume responsibility or liability for any possible factual inaccura-
Purely mineral fertilisation results in considerably lower numbers and biomass cies or damage resulting from the application of recommendations.
of earthworms compared to organic and, in a lesser degree, to combined mineral
and organic (conventional) fertilisation. Results from the DOK long-term trial in 2nd edition 2022 © FiBL
Switzerland (average from 3 years). This work is entirely copyrighted.