Agriculture Reference
In-Depth Information
(Kausar et al.
2010
; Hachicha et al.
2012
; Razali et al.
2012
; Cheng et al.
2011
; Par-
adelo et al.
2013
; Thomas et al.
2013
). Zhao et al. (
2011b
) carried out the analysis
in yet finer detail by determining the C:N ratio for different soluble fractions, when
using either straw or sawdust as the cellulosic component for composting. Losses in
carbon content in the course of composting were mainly traceable to degradation of
the cellulose and hemicellulose components.
3.2.1.2
Bulking and Air Access
In addition to allowing some control over the C:N ratio, another key purpose of add-
ing plant-based materials to a compost mixture can be to provide structure and chan-
nels for aeration (Hubbe et al.
2010
; Zhao et al.
2011a
,
b
). Access to oxygen, through-
out a composting pile, is essential in order to minimize the possibility of anaerobic
micro-zones (Luz Cayuela et al.
2012
). Conventional composting is essentially an
aerobic process, and the presence of at least some oxygen is necessary to avoid the
formation of greenhouse gases, foul odors, and toxic conditions. The particle size
of the lignocellulosic component needs to be optimized. For instance, Yanez et al.
(
2010
) found that reduction of the particle size to about 1 cm allowed more rapid
chemical changes during composting and a higher relative content of humic sub-
stances after a fixed period of composting. Doublet et al. (
2011
) found that the choice
of bulking agent affected mainly the rate of composting, rather than the final results
evaluated after a long period. Serramia et al. (
2010
) found that the nature of the bulk-
ing agents mainly affected the rate of changes during early phases of composting,
while not having much effect on the time required to reach full maturity of compost.
3.2.1.3
Moisture
As confirmed by the work of Yanez et al. (
2010
), the moisture content of a compost
pile can be expected to affect the outcome of the process. In the cited work relative-
ly high moisture content tended to promote the progress of composting. As docu-
mented by Karadag et al. (
2013
), the moisture content can be expected to decrease
during the course of composting; such an effect is consistent with the elevation of
temperatures during composting, as well as the convection of air through a com-
post pile (Hubbe et al.
2010
). Zambra et al. (
2011
) showed, by means of a dynamic
model, that the initial moisture content can affect the maximum temperatures that
are reached during composting; control of such temperatures can be important to
avoid cases of spontaneous combustion within compost piles.
3.2.1.4
Inoculation
The term “inoculation” implies the addition of living bacteria or fungi (including
spores) to a mixture of materials to be composted. Because bacteria and fungi are
