N.º 24 - PDF - Instituto Politécnico de Castelo Branco

the buffer was replaced with sodium bicarbonate on bicarbonate
equivalents.
Pressure values were corrected for the quantity of substrate
organic matter (OM) incubated and gas released from
blanks (i.e., gas productions in buffered RF without sample).
Gas production of all samples were analysed in duplicate.
Cumulative gas was expressed as millilitre of gas
produced per mg of OM incubated (Figures 1a-4a). The
rate of gas production (Figures 1b-4b) was calculated by
first derivate from the cumulative gas production profiles
(Cone et al., 1997). The numerous combinations between
and within different samples, dilutions and N presence or
absence, as well as its interactions, were investigated with
multiple analysis (SPSS, 2007).
400
A
30
B
Maize
Gas production (ml/g OM incubated)
350
300
250
200
150
100
50
25
20
15
10
5
MGF
SBM
Citrus
Tapioca
Wheat
0
0 20 40 60 80
Time (h)
0
0 10 20 30 40
Time (h)
Figure 1 - Cumulative gas production profile (ml/g OM incubated) (A) and rate (ml/g OM/h) (B) in 1:9 dilutions without N in the medium.
Gas production (ml/g OM incubated)
500
450
400
350
300
250
200
150
100
50
0
A
0 20 40 60 80
Time (h)
Gas production rate (ml/g OM/h)
70
60
50
40
30
20
10
0
B
Maize
MGF
SBM
Citrus
Tapioca
Wheat
0 10 20 30 40
Time (h)
Figure 2 - Cumulative gas production profile in (ml/g OM incubated) (A) and rate (ml/g OM/h) (B) 1:2 dilutions without N in the medium.
Gas production (ml/g OM incubated)
400
350
300
250
200
150
100
50
A
Gas production rate (ml/g OM/h)
70
60
50
40
30
20
10
B
Maize
MGF
SBM
Citrus
Tapioca
Wheat
0
0 20 40 60 80
Time (h)
0
0 10 20 30 40
Time (h)
Figure 3 - Cumulative gas production profile (ml/g OM incubated) (A) and rate (ml/g OM/h) (B) in 1:9 dilutions with N in the medium.
12
n.º 24 Ano 18, 2010