Agriculture Reference
In-Depth Information
Recently, Hu et al. (
2011
) studied that increased rate of decomposition of amor-
phous cellulose and hemicellulose fractions occur quickly by microbial conversion
processes at ambient conditions of temperature and pH. The number of cellulolytic
microorganisms increased with the addition of rock phosphate that too conserved
nitrogen by decreasing the number of denitrifying bacteria (Hassimi et al.
2013
;
Mehta et al.
2013
). Although, with addition of calcium phosphates, nitrogen fixa-
tion may increase (Tariq et al.
2013
). There is generally sufficient phosphate in the
organic wastes for meeting out the requirement of microorganisms, which need
about 5 to 20 % only as much P as N. However, experiments at IARI, New Delhi in
India have shown that application of rock phosphate is important for nitrogen con-
servation and enrichment of organic manures (Gaur et al.
1982
). They also reported
that the addition of rock phosphate at 1.0 % (w/w) increase the decomposition of
paddy straw by involving cellulolytic fungi. Increased amount of rock phosphate
(2-3 %) showed slight reduction in the intensity of decomposition. Khan and Bhat-
nagar (
1977
) observed the solubilization of insoluble phosphate by microorganisms
and reported that
Aspergillus niger, Pencillium
spp. and other phosphate solubiliz-
ing microorganisms remains were most active in the soils. The solubilization of
rock phosphate was found to be stationary corresponding increase in the concen-
tration of rock phosphate up to a level of 4.0 %. After increasing the concentration
the rock phosphate inhibited by its own solubilization which was attributed to the
exploration of fluoride. In fact, sodium fluoride inhibited the microbial growth. The
effect of organic matter in reducing the intensity of phosphate fixation by the soil
sequioxides and maintenance of soil fertility by the use of organic manures along
with super phosphate was advocated by Datta and Srivastava (
1963
). Organic mat-
ter applied to soil at the rate of 1 % proved more effective in increasing the available
P from the native as well as added P sources (Vyas and Motiramani
1971
). It was
observed that both organic acid and humus and organic fractions of decomposing
organic matter was more efficient releasing phosphorus from rock phosphate and
tri-calcium phosphate and reducing phosphorus fixation in soil (Gaur
1969
; Pareek
and Gaur
1973
). The quality of compost prepared from mixture of paddy straw
grass and water-hycinth was improved when rock phosphate was supplemented to
it with or without pyrite. They concluded that enrichment of compost occurred with
the increase in the concentration of calcium and other micronutrients particularly of
iron, manganese and zinc. The amendment of the finished compost with 1 % rock
phosphate and inoculation with nitrogen fixing of finished urban compost and fresh
moist sludge in a 2:1 proportions and amendments with 1 % rock phosphate resulted
in compost enrichment in nitrogen with a C/N ratio less than 10 (Kolay
2007
).
Investigators have reported that calcium phosphate increases the rate of decom-
position and nitrogen conservation (Arzamasova and Kuzmenkova
1962
) but more
than 2 % of calcium inhibited the rate of decomposition (Gaur et al.
1980
). Addition
of optimum amount of calcium salts of both acids and alkaline soils includes benefi-
cial effect, thus bring about a condition suitable for plant growth and development
(Hausenbuiller
1963
). Ali (
1970
) while studying the effect of few acid soils, addi-
tion of calcium salts increase the availability of nitrogen and phosphorus. Similarly,
increase in nitrogen was reported by Srivastava et al. (
1971
). They observed that
maximum availability of nitrogen and phosphorus obtained by the addition of cal-
cium carbonate and calcium acetate respectively.
