lower than the room temperature during the incubation period (31.07 Æ 0.5,
29.71 Æ 0.27, 30.85 Æ 0.14, 30.35 Æ 0.24, and 30.46) (Bhattacharjee and Chaudhuri
2002). This may be due to the tendency for the avoidance of “heat shock” by the
baby worm following emergence.
11.5.1.1 Moisture Content
Moisture is the limiting factor for earthworm survival, as earthworms can’t respire in
dry soils. There is a strong relationship between the moisture content of the organic
wastes and the growth rate of earthworms (Dominguez and Edwards 2011). Bedding
moisture of 70–80% for E. eugeniae, E. fetida, P. excavatus, 28–42% for
D. modiglianii, and 25–30% for D. nepalensis, P. elongata, and L. mauritii are
required for their reproduction (Bhattacharjee and Chaudhuri 2002). E. andrei and
E. fetida grow more rapidly between 80 and 90% moisture in organic wastes
(Domínguez and Edwards 1997).
11.5.1.2 pH
Most epigeic earthworm species favour pH level in the acidic side of neutral
(Edwards and Bohlen 1996) when subjected to pH gradient 5–9.
11.5.1.3 Aeration
Earthworms have no specialized respiratory organ, and oxygen and carbon dioxide
diffuse through their body wall, thus they are highly sensitive to anaerobic
conditions.
11.5.1.4 Ammonia and Salts
Earthworms are very sensitive to ammonia and cannot survive in organic wastes
having a high level of this cation (e.g. fresh poultry dropping). They also die in
wastes with large quantities of inorganic salts (fresh kitchen waste). Both inorganic
salt and ammonia have sharp cut-off points between toxic and nontoxic (Edwards
1988). Organic waste contains a high level of ammonia, and salts can become
acceptable to earthworms after removal of ammonia by a period of
pre-composting or by several washing with water.
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P. Chaudhuri and S. Debnath
29.71 Æ 0.27, 30.85 Æ 0.14, 30.35 Æ 0.24, and 30.46) (Bhattacharjee and Chaudhuri
2002). This may be due to the tendency for the avoidance of “heat shock” by the
baby worm following emergence.
11.5.1.1 Moisture Content
Moisture is the limiting factor for earthworm survival, as earthworms can’t respire in
dry soils. There is a strong relationship between the moisture content of the organic
wastes and the growth rate of earthworms (Dominguez and Edwards 2011). Bedding
moisture of 70–80% for E. eugeniae, E. fetida, P. excavatus, 28–42% for
D. modiglianii, and 25–30% for D. nepalensis, P. elongata, and L. mauritii are
required for their reproduction (Bhattacharjee and Chaudhuri 2002). E. andrei and
E. fetida grow more rapidly between 80 and 90% moisture in organic wastes
(Domínguez and Edwards 1997).
11.5.1.2 pH
Most epigeic earthworm species favour pH level in the acidic side of neutral
(Edwards and Bohlen 1996) when subjected to pH gradient 5–9.
11.5.1.3 Aeration
Earthworms have no specialized respiratory organ, and oxygen and carbon dioxide
diffuse through their body wall, thus they are highly sensitive to anaerobic
conditions.
11.5.1.4 Ammonia and Salts
Earthworms are very sensitive to ammonia and cannot survive in organic wastes
having a high level of this cation (e.g. fresh poultry dropping). They also die in
wastes with large quantities of inorganic salts (fresh kitchen waste). Both inorganic
salt and ammonia have sharp cut-off points between toxic and nontoxic (Edwards
1988). Organic waste contains a high level of ammonia, and salts can become
acceptable to earthworms after removal of ammonia by a period of
pre-composting or by several washing with water.
190
P. Chaudhuri and S. Debnath