Agriculture Reference
In-Depth Information
forms, helminth ova and human viruses in different types of waste. Direct
means of reduction in these microbial numbers during gut passage might
be due to the digestive enzymes and mechanical grinding, while indirect
means of pathogen removal might be due to promotion of aerobic condi-
tions which could bring down the load of coliforms (Monroy et al. 2009;
Edwards 2011; Aira et al. 2011).
9.7 ROLE OF VERMICOMPOST IN PLANT GROWTH
PROMOTION
Use of vermicomposts as biofertilizers has been increasing recently due to
its extraordinary nutrient status, and enhanced microbial and antagonistic
activity. Vermicompost produced from different parent material such as
food waste, cattle manure, pig manure, etc., when used as a media sup-
plement, enhanced seedling growth and development, and increased pro-
ductivity of a wide variety of crops (Edwards and Burrows 1988; Wilson
and Carlile 1989; Buckerfield and Webster 1998; Edwards 1998; Subler
et al. 1998; Atiyeh et al. 2000c). Vermicompost addition to soil-less bed-
ding plant media enhanced germination, growth, flowering and fruiting
of a wide range of green house vegetables and ornamentals (Atiyeh et
al. 2000a, b, c), marigolds (Atiyeh et al. 2001), pepper (Arancon et al.
2003a), strawberries (Arancon et al. 2004b) and petunias (Chamani et al.
2008). Vermicompost application in the ratio of 20:1 resulted in a signifi-
cant and consistent increase in plant growth in both field and greenhouse
conditions (Edwards et al. 2004), thus providing a substantial evidence
that biological growth promoting factors play a key role in seed germi-
nation and plant growth (Edwards and Burrows 1988; Edwards 1998).
Investigations revealed that plant hormones and plant-growth regulating
substances (PGRs) such as auxins, gibberellins, cytokinins, ethylene and
abscisic acid are produced by microorganisms (Barea et al. 1976; Arshad
and Frankenberger 1993).
Several researchers have documented the presence of plant growth
regulators such as auxins, gibberellins, cytokinins of microbial origin
(Krishnamoorthy and Vajranabhiah 1986; Grappelli et al. 1987; Tomati
et al. 1988; Muscolo et al. 1999) and humic acids (Senesi et al. X1992;
