Agriculture Reference
In-Depth Information
water hyacinth. Water hyacinth compost is entirely suitable to be used as organic
manure. Further, preparation of such compost will off-set the cost of cleaning the ir-
rigation system of this weed and will prevent the health hazard arising from leaving
the plant material on the banks of the river and canals. Water hyacinth compost has
been shown to have positive effects on crop growth when using the water hyacinth
compost as organic fertilizer.
The compost product already contains a well-working flora of microorganisms
will be favorable for the soil. Applying the water hyacinth directly without any
other processing than sun-drying seems to be the best alternative in small scale use,
due to relatively small loses of nutrients and workload required. This option also
does not require any large investments or new technology. If the fresh water hya-
cinth could be applied as mulch on the fields, the labor need for weeding could be
used for handling the water hyacinths instead.
4.5
Compost amended with Nitrogen Fixing Rhizobia
Addition of compost borne nutrients, micronutrients and organic matter to soil may
enhance the growth of symbiotic bacteria. Various workers (Bouldin et al.
1985
;
Madriaga and Angle
1992
) observed increase in nodulation in crop legumes. Bhard-
waj and Gaur (
1970
) obtained better growth and activity of rhizobia in soil mulched
with compost. The organic acids present in compost helps in release of combined P
into free available form (Struthers and Seiling
1950
). Acids prevent precipitation of
P by Fe or Al (Gaur
1986
), for instance increase in carbolic acid group and decrease
in chain length showed positive effect on P availability. On the other hand, humic
acid released various micro-nutrients like Fe, Mn, Cu and Zn (Elgala and Schlich-
ling
1976
). Even, the addition compost detoxifies certain pesticides including DDT
(Pareekh and Gaur
1973
) and BHC (Gaur et al.
1975
).
Interestingly, the shoot weight of the tree legumes increased on application of
compost and that the maximum dry matter accumulation was due to that the EC on
degradation provided better release of nutrients which favored microbial growth/
activity resulting into improved biomass. The influence of compost mulched soil
was exhibited more on
Leucaena leucocephala
than that of
Dalbergia sisoo.
Rhizobia promote plant growth using several mechanistic strategies as well as
via fixing nitrogen symbiotically and enhance overall crop protection and produc-
tion (Maheshwari et al.
2013
). Rhizobia symbiosis with plants depends upon sev-
eral factors. Water hyacinth,
Eichhornia crassipes
is a chief weed to utilize in prepa-
ration of compost with its perceived benefits in improvement of crop productivity
and limiting its disease. Recent technique of blending
Rhizobium
inoculant with
hyacinth compost is compatible option for plant growth promotion and pest sup-
pression. High nutrient content in water hyacinth compost can stimulate
Rhizobium
nodulation and nitrogen fixation, consequently improving plant growth and pest
resistance. Naluyange et al. (
2014
) conducted a field study with two trials to assess
the compatibility of commercial
Rhizobium
inoculant, DAP, cattle farmyard ma-
