Agriculture Reference
In-Depth Information
Table 5.1
Different
maturity and stability
parameters
Maturity parameters
Stability parameters
C:N ratio
Temperature
C
w
/N
org
pH
HA/FA ratio
EC
HI
WSC
CEC
Total organic carbon/OM loss
CEC/TOC ratio
Microbial diversity population/activity
NH
4
and NO
3
Enzyme activity
O
2
and CO
2
respiratory
Germination index
5.3
Maturity and Stability Assessment for
Compost Quality
Composts prepared from different organic waste materials differed in their quality
and stability; and quality is closely related to stability and maturity. Hence, it is
important to define maturity and stability. Compost maturity is the degree or level
of completeness of composting. It is described by several physical, chemical and
biological properties and therefore maturity is best assessed by measuring two or
more parameters of compost. Compost stability refers to a specific stage or de-
composition or state of organic matter during composting, which is related to the
type of organic compounds remaining and the resultant biological activity in the
material.
Several parameters have been proposed for evaluating compost maturity and
stability (Iglesias Jiménez and Pérez García
1992
; Bernal et al.
1998
,
2009
; Wu
et al.
2000
; Raj and Antil
2011
; Raj and Antil
2012a
,
b
; Antil and Raj
2012
; Antil
et al.
2012
). However, there is no single method that can be universally applied to
all types of composts due to variation of materials and composting technology. (He
et al.
1995
; Itavaara et al.
2002
; Benito et al.
2003
; Chang and Chen
2010
). The
parameters are grouped into maturity and stability shown in Table
5.1
.
In addition to above parameters, the physical characteristics such as colour,
odour, particle size, appearance of larvae of secondary consumers also show the
decomposition stage, but give the little information with regard to degree of matura-
tion. The maturity of compost, which may defined as the degree of compost stabil-
ity in physical, chemical and biological properties is an important factor affecting
successful application in agriculture and its impact on environment. The parameters
proposed by several workers are presented in Table
5.2
. Parameters or criteria pro-
posed or indicated in the literature are grouped into physical parameters, chemical
parameters and biological parameters.
5.3.1
Physical Parameters
Physical parameters are frequently used but they give only general information re-
garding maturity of compost.
