of soil through their burrowing activities, producing macropores that have a significant impact on water absorption and are therefore critical for water-supplying crops,
as well as managing surface runoff and erosion (Bertrand et al. 2015). The improved
infiltration rates due to burrows created by the earthworms also reduced the soil
erosion by 50% (Shuster et al. 2002). On the other hand, many earthworms having
an endogeic ecological category have also been shown to produce small casts that
support surface sealing and contribute to soil erosion (Blanchart et al. 2004; Bertrand
et al. 2015). Such discrepancies between the effects of earthworm on soil structure,
water absorption and soil erosion are likely due to the fact that this impact depends
on (1) the precipitation system, (2) earthworm abundance, (3) earthworm organisms
and (4) the amount of organic matter available on soil surface.
19.3.4 Improve Water-Holding Capacity
Water is the key productivity limiting factor in all terrestrial ecosystems because all
vegetation needs huge amounts of water for its growth and fruit production (Munnoli
and Bhosle 2011). It is therefore of the utmost importance to ‘save water’as much as
possible and has been adopted as a motto of the world. Earthworms have the capacity
to increase the water-holding capacity of soils by fragmenting organic matter and
increasing soil porosity. Vermicast increases the softness of soil thus requiring less
tillage and irrigation (Guild 1955). Ernst et al. (2008) showed that earthworm
belonging to different ecological groups (Epigeic, Anecic, Endogeic) affects soil
water characteristics. The anecic Lumbricus terrestris and the endogeic
Aporrectodea caliginosa enhanced drying in the 0–15 cm soil layer by increasing
soil aeration and subsequently evaporation through their burrows. In contrast, the
epigeic Lumbricus rubellus tended to favour water storage in the topsoil. This is
probably due to the fact that Lumbricus rubellus deposited plants litter at the soil
surface rather than burying it, which prevents evaporation. Aporrectodea caliginosa
induced higher water infiltration rates and faster water discharges to the subsoil than
other species, probably because its burrows are temporary and are continually being
rebuilt (Bertrand et al. 2015). Munnoli and Bhosle (2011) studied the capacity of
vermicompost egested by earthworms in monoculture (vermicompost egested by
one earthworm species) and polyculture (vermicompost egested by more than one
earthworm species) in the vermireactors by using sugar industry wastes. They
reported that vermicompost of monoculture experiment can hold 110–170% water,
while polyculture can hold 140–210% of the water in the soil. There experiment
clearly states that mixture or combination of different earthworm species in the soil
has more water-holding capacity as compared to the field having single earthworm
species or without any earthworms.
19 Earthworm Communities and Soil Structural Properties
339
as well as managing surface runoff and erosion (Bertrand et al. 2015). The improved
infiltration rates due to burrows created by the earthworms also reduced the soil
erosion by 50% (Shuster et al. 2002). On the other hand, many earthworms having
an endogeic ecological category have also been shown to produce small casts that
support surface sealing and contribute to soil erosion (Blanchart et al. 2004; Bertrand
et al. 2015). Such discrepancies between the effects of earthworm on soil structure,
water absorption and soil erosion are likely due to the fact that this impact depends
on (1) the precipitation system, (2) earthworm abundance, (3) earthworm organisms
and (4) the amount of organic matter available on soil surface.
19.3.4 Improve Water-Holding Capacity
Water is the key productivity limiting factor in all terrestrial ecosystems because all
vegetation needs huge amounts of water for its growth and fruit production (Munnoli
and Bhosle 2011). It is therefore of the utmost importance to ‘save water’as much as
possible and has been adopted as a motto of the world. Earthworms have the capacity
to increase the water-holding capacity of soils by fragmenting organic matter and
increasing soil porosity. Vermicast increases the softness of soil thus requiring less
tillage and irrigation (Guild 1955). Ernst et al. (2008) showed that earthworm
belonging to different ecological groups (Epigeic, Anecic, Endogeic) affects soil
water characteristics. The anecic Lumbricus terrestris and the endogeic
Aporrectodea caliginosa enhanced drying in the 0–15 cm soil layer by increasing
soil aeration and subsequently evaporation through their burrows. In contrast, the
epigeic Lumbricus rubellus tended to favour water storage in the topsoil. This is
probably due to the fact that Lumbricus rubellus deposited plants litter at the soil
surface rather than burying it, which prevents evaporation. Aporrectodea caliginosa
induced higher water infiltration rates and faster water discharges to the subsoil than
other species, probably because its burrows are temporary and are continually being
rebuilt (Bertrand et al. 2015). Munnoli and Bhosle (2011) studied the capacity of
vermicompost egested by earthworms in monoculture (vermicompost egested by
one earthworm species) and polyculture (vermicompost egested by more than one
earthworm species) in the vermireactors by using sugar industry wastes. They
reported that vermicompost of monoculture experiment can hold 110–170% water,
while polyculture can hold 140–210% of the water in the soil. There experiment
clearly states that mixture or combination of different earthworm species in the soil
has more water-holding capacity as compared to the field having single earthworm
species or without any earthworms.
19 Earthworm Communities and Soil Structural Properties
339