C - Lublin

N2O-N [mg kg -1 ]
100
80
60
40
20
0
-20
y = -12.073Ln(x) +
23.933
R 2 = 0.336***
0 2 4 6 8 10
O 2 [%]
Total N 2O-N [mg kg -1 ]
80
70
60
50
40
30
20
10
0
170 190 210 230 250 270
Eh [mV]
Fig. 1. N 2 O emission vs. O 2 content
for the day of maximum emission.
Fig. 2. N 2 O emission as a function
of Eh value (●emission ○absorption).
Organic matter availability Denitrification is a respiratory process, which
requires an easily oxidisable organic substrate. The presence of readily metabolize
organic matter and the availability of water soluble organic matter are closely
correlated with the rate biological denitrification and hence the potential production
of N 2 O from soil. There is observed very high correlation between N 2 O emission
and organic matter content (Fig. 3 Włodarczyk, 2000).
Dehydrogenases These enzymes conduct a broad range of oxidative activities
that are responsible for degradation, i.e., dehydrogenation, of organic matter. The
amount of nitrous oxide formed due to denitrification showed high positive
correlation with dehydrogenase activity (Fig. 4 Włodarczyk et al., 2001).
N2O-N mg kg -1 d -1
50
40
30
20
10
0
y = 24.699x - 11.924
R 2 = 0.946***
N2O-N mg kg -1
250
200
150
100
50
y = 671.55x 0.84
R 2 = 0.51**
-10
0 0,5 1 1,5 2 2,5
0
O.M %
0 0,1 0,2 0,3
nmol formazan g -1 min -1
Fig.3 N 2 O emission as a function
of organic matter content.
Fig.4 N 2 O emission as a function
of dehydrogenase activity.
160