to enteric fermentation of livestock and manure management as well as CO 2 emissions
linked to fossil fuel consumption for mechanisation, heating, transport of feed
and fertiliser manufacture. These components of the GHG balance were estimated
by Garnier et al. [35] for the Seine basin agriculture over the 1852–2015 period.
Soil N 2 O emissions were estimated from an empirical relationship with exogenous
N inputs (as synthetic fertilisers and manure), rainfall and temperature (Fig. 7a).
They fit well with the predictions of the STICS model in agricultural zones
[13]. CH 4 emissions from ruminants and monogastrics were estimated using livestock
numbers and time-dependent emissions factors. CO 2 emissions were calculated following the ClimAgri methodology [36]. While CH 4 emissions did not change much
over the period under study in the Seine basin, owing to the gradual reduction of
0
200
400
600
800
1000
1850
1900
1950
2000
hum input, kgC/ha/y
Humified orgC input to cropland
0
10
20
30
40
50
60
1850
1900
1950
2000
org C, tonC/ha
orgC stock in cropland (0-30 cm)
inert orgC
labile orgC
l
-100
-50
0
50
100
150
200
1850
1900
1950
2000
Csequestr, kgC/ha/y
orgC sequestration in cropland soil
5 5
n op op
Br
N-PdC
L Am
LC
L Av
Pic
B
M
SM
CO
Gde L
IdF
E
E&L
2000-2014
Cropland C sequestration
in ‰ yr -1 of the current stock 0-30cm
< 0
0 - 1
1 - 2
2 - 3
3 - 4
> 4
a.
b.
c.
d.
e.
1971-2016
Net SON storage or mineralization
in kgN/ha/yr over the period
< -10
- 5 to -10
- 5 to + 5
+5 to +10
+10 to +20
Fig. 6 (a) Long-term trends of humified organic carbon inputs to cropland soil of the Seine basin.
(b) Calculated evolution of the labile and inert C stock in the 30-cm top soil of cropland. (c) Rate of
C sequestration in kgC/ha/year and (d) in ‰ year
À1 of the total stock in the 30-cm top soil of
cropland (data from [30]). (e) Distribution of SON storage per agricultural district simulated by
STICS in arable land from 1971 to 2013 [20]
The Seine Watershed Water-Agro-Food System: Long-Term Trajectories of C. . .
101
linked to fossil fuel consumption for mechanisation, heating, transport of feed
and fertiliser manufacture. These components of the GHG balance were estimated
by Garnier et al. [35] for the Seine basin agriculture over the 1852–2015 period.
Soil N 2 O emissions were estimated from an empirical relationship with exogenous
N inputs (as synthetic fertilisers and manure), rainfall and temperature (Fig. 7a).
They fit well with the predictions of the STICS model in agricultural zones
[13]. CH 4 emissions from ruminants and monogastrics were estimated using livestock
numbers and time-dependent emissions factors. CO 2 emissions were calculated following the ClimAgri methodology [36]. While CH 4 emissions did not change much
over the period under study in the Seine basin, owing to the gradual reduction of
0
200
400
600
800
1000
1850
1900
1950
2000
hum input, kgC/ha/y
Humified orgC input to cropland
0
10
20
30
40
50
60
1850
1900
1950
2000
org C, tonC/ha
orgC stock in cropland (0-30 cm)
inert orgC
labile orgC
l
-100
-50
0
50
100
150
200
1850
1900
1950
2000
Csequestr, kgC/ha/y
orgC sequestration in cropland soil
5 5
n op op
Br
N-PdC
L Am
LC
L Av
Pic
B
M
SM
CO
Gde L
IdF
E
E&L
2000-2014
Cropland C sequestration
in ‰ yr -1 of the current stock 0-30cm
< 0
0 - 1
1 - 2
2 - 3
3 - 4
> 4
a.
b.
c.
d.
e.
1971-2016
Net SON storage or mineralization
in kgN/ha/yr over the period
< -10
- 5 to -10
- 5 to + 5
+5 to +10
+10 to +20
Fig. 6 (a) Long-term trends of humified organic carbon inputs to cropland soil of the Seine basin.
(b) Calculated evolution of the labile and inert C stock in the 30-cm top soil of cropland. (c) Rate of
C sequestration in kgC/ha/year and (d) in ‰ year
À1 of the total stock in the 30-cm top soil of
cropland (data from [30]). (e) Distribution of SON storage per agricultural district simulated by
STICS in arable land from 1971 to 2013 [20]
The Seine Watershed Water-Agro-Food System: Long-Term Trajectories of C. . .
101