. 2014 Dec 10;4:7406. doi: 10.1038/srep07406

Table 3. Areas of cropland, forest, grassland and desert/semi-desert in China and soil NO emissions from the four land cover types.

	Area	Percentage of total land area	Soil NO emissions	Percentage of anthropogenic NO_x emission
	10⁶ ha	%	Gg N yr⁻¹	%
Cropland	163.42^a	17.02	442.83 (296.67–699.15)	6.51 (4.36–10.28)
Forest	258.26^b	22.64	371.96 (153.37–747.95)	5.47 (2.26–11.00)
Grassland	191.65^b	26.15	328.98 (130.33–527.63)	4.84 (1.92–7.76)
Deserts and semi-deserts	262.20^c	27.31	82.59 (7.87–157.32)	1.21 (0.12–2.31)
Total	875.53	93.12	1226.33 (588.24–2132.05)	18.03 (8.65–31.35)

Note: a, from China Statistical Yearbook 2013 (133.28 × 10⁶ ha for upland fields and 30.14 × 10⁶ ha for rice fields in 2012); b, from Wu et al.⁶⁰; c, from Zhao et al.,⁶¹.