Agriculture Reference
In-Depth Information
Masciandaro et al. 1997; Atiyeh et al. 2002) in vermicompost in appre-
ciable quantities. Cytokinins produced by
Bacillus
and
Arthrobacter
spp.
in soils increase the vigour of seedlings (Inbal and Feldman 1982; Jagnow
1987). Microbially produced gibberellins infl uence plant growth and de-
velopment (Mahmoud et al. 1984; Arshad and Frankenberger 1993) and
auxins produced by
Azospirillum brasilense
affects the growth of plants
belonging to paoceae (Barbieri et al. 1988). Extensive investigations on
the biological activities of humic substances showed that they also posses
plant growth stimulating property (Chen and Aviad 1990). Humic sub-
stances increased the dry matter yields of corn and oat seedlings (Lee and
Bartlett 1976; Albuzio et al. 1994); number and length of tobacco roots
(Mylonas and Mccants 1980); dry weights of roots, shoots and number
of nodules of groundnut, soyabean and clover plants (Tan and Tantiwira-
manond 1983) and vegetative growth of chicory plants (Valdrighi et al.
1996) and induced root and shoot formation in plant tissue culture (Goe-
nadi and Sudharama 1995). High levels of humus have been reported from
vermicomposts originating from food wastes, animal manure, sewage and
paper mill sludges (Atiyeh et al. 2002; Canellas et al. 2002; Arancon et al.
2003c). The humic and fulvic acid in the humus dissolves insoluble miner-
als in the organic matter and makes them readily available to plants and
in addition they also help plants to overcome stress and stimulates plant
growth (Sinha et al. 2010). Studies on biological activities of vermicom-
post derived humic substances, revealed that they had similar growth-pro-
moting hormonal effect (Dell'Agnola and Nardi 1987; Nardi et al. 1988;
Muscolo et al. 1993). The humic materials extracted from vermicomposts
have been reported to produce auxin-like cell growth and nitrate metabo-
lism in carrots (
Daucus carota
) (Muscolo et al. 1996). Humates obtained
from pig manure vermicompost increased growth of tomato (Atiyeh et al.
2002) and those obtained from cattle, food and paper waste vermicompost
increased the growth of strawberries and peppers (Arancon et al. 2003a).
Earthworms produce plant growth regulators (Gavrilov 1963). Since
earthworms increase the microbial activity by several folds they are con-
sidered as important agents which enhance the production of plant growth
regulators (Nielson 1965; Graff and Makeschin 1980; Dell'Agnola and
Nardi 1987; Grappelli et al. 1987; Tomati et al. 1987, 1988; Edwards and
