Table 5.1 N budgets of the world, the United States, the EU27, and China
World
United
States
EU27 China China
1860
a
Early
1990s
a
2010
b
2000
c
2002
d
2000
e
2015
e
Nr creation, Tg N
year
À1
135
263
278
30.7
22.3
49.7
70.9
NBNF
120
107
58
6.4
0.5
7.1
7.7
CBNF
15
31.5
60
7.7
1.0
4.8
4.5
HBNF-SF
0
88
100
10.9
11.4
26.9
35.0
HBNF-IN
0
12
20
4.2
6.0
3.4
13.4
NOx-FF
0.3
24.5
40
5.7
3.4
4.3
7.0
Nr loss, Tg N year
À1
N 2
98
115
200
–
11
20.0
28.7
NH 3
14.9
52.6
60
3.1
3.3
11.3
14.8
NO x
7.7
40.6
40
6.2
3.5
5.0
7.9
N 2 O
8.1
10.9
13
0.8
0.7
1.1
1.5
Leaching and runoff
–
–
–
9.0
6.2
13.5
24.3
Export by air
13.1
46
100
–
2.4
4.5
5.1
Export by water
69.8
118.1
40–70 1.9
4.5
13.5
24.3
Export to ocean
27
47.8
80
–
–
4.3
7.8
Accumulation, Tg N year
À1
Cropland
–
–
–
0.8
À3.4
8.7
7.6
Forest
–
–
–
0.4
0.7
4.7
6.9
Grassland
–
–
–
0.3
À0.03 2.0
2.3
Socioeconomic factors
Land area, million
km
2
134.3 148.9
148.9
9.8
4.4
9.6
9.6
Population, million
~1500 5283.1
6929.7 310.4
500.4 1267.4 1376.1
GDP, trillion, PPP,
$2005
–
22.55
65.49
13.1
13.8
3.4
14.5
Unit, Tg N year
À1
; NBNF, natural biological N fixation; CBNF, cultivated biological N fixation;
HBNF-SF, Haber-Bosch N fixation for synthetic fertilizer use; HBNF-IN, Haber-Bosch N fixation
for industrial N use; NO x -FF, NO x emission via fossil fuel combustion. The socioeconomic factors
are all on a yearly basis. GDP is at 2005 prices and adjusted for purchasing power parity (PPP)
a Adapted from Galloway et al. (Galloway et al. 2004)
b
Adapted from Fowler et al.(Fowler et al. 2013)
c Adapted from EPA.(EPA 2011)
d
Adapted from De Vries et al. (De Vries et al. 2011)
e Adapted from this study
104
B. Gu and X. Zhang