national statistical data (National Bureau of Statistics of China 2016) showed that per
capita GDPs in Beijing, Shanghai, Jiangsu, and Zhejiang were 106,497, 103,896,
87,995, and 77,644 RMB yuan (¥) in 2015, respectively, which were much higher
than those reported in Gansu (26165 ¥) and Xinjiang (40648 ¥).
13.2.3 Nitrogen Application on Cereals and Vegetables
Globally, approximately 50% of Nr produced by the Haber-Bosch process is consumed by major cereals including wheat (Triticum aestivum L.), maize (Zea mays
L.), and rice (Oryza sativa L.) (Ladha et al. 2016). From farmer surveys and data
mining, N fertilizer application on maize, wheat, and rice consumed approximately
15%, 18%, and 21%, respectively, of the total N fertilizer input to Chinese farmlands
during 2000–2003 (Wu et al. 2016). The amount of N fertilizer applied to maize
increased by 4% during 2008–2009, with a decrease in application on rice and wheat
(Wu et al. 2016). On average, the N application on wheat, maize, and rice increased
sharply from 45–60 kg N ha
À1 during 1970–1979 to 200–300 kg N ha
À1 in 2010
(Cui et al. 2014a; Wu et al. 2016). Additionally, the N fertilizer application rate of
wheat was higher in the North China Plain, while the highest N input rate of rice
occurred in Yangtze River region.
Furthermore, the cultivated land area of vegetables has increased nearly six times
from 1978 to 2011, resulting in a significant increase in vegetable production. The
vegetable planted area accounted for 12.1% of the total national crop-sown area in
2011 (National Bureau of Statistics of China 2016). Vegetable fields are often
characterized by intensive crop rotations (multiple harvests within a single year);
thus, more N fertilizer is applied to vegetables compared to maize, wheat, and rice.
For example, the average annual N input including both chemical fertilizers and
manure was 3239 kg N ha
À1 in some vegetable greenhouses in northern China
(Ju et al. 2006). Our results (Ti et al. 2015) showed that total N input in vegetable
cropping system in 2010 was 8.04 Tg N year
À1 . Chemical fertilizer N input in the
greenhouse system (478 kg N ha
À1 per season) was much higher than that in the
open-air system (201 kg N ha
À1 per season).
Fruits and tea also consumed a large amount of N fertilizer. Nitrogen applied to
fruit and tea farmland accounted for 13% and 17% of the total N input on Chinese
farmland during the 2000–2003 and 2008–2009 periods, respectively. The rate of
chemical N fertilizer use on conventional fruit and tea farmland was 330 and
536 kg N ha
À1 , respectively, which was much higher than that of maize, rice, and
wheat (Meng et al. 2017). Overall, compared to other regions/countries, such as the
USA and the EU, N use in China’s agricultural systems is much higher (Zhang et al.
2015).
13 Nitrogen Regulation in China’s Agricultural Systems
301
capita GDPs in Beijing, Shanghai, Jiangsu, and Zhejiang were 106,497, 103,896,
87,995, and 77,644 RMB yuan (¥) in 2015, respectively, which were much higher
than those reported in Gansu (26165 ¥) and Xinjiang (40648 ¥).
13.2.3 Nitrogen Application on Cereals and Vegetables
Globally, approximately 50% of Nr produced by the Haber-Bosch process is consumed by major cereals including wheat (Triticum aestivum L.), maize (Zea mays
L.), and rice (Oryza sativa L.) (Ladha et al. 2016). From farmer surveys and data
mining, N fertilizer application on maize, wheat, and rice consumed approximately
15%, 18%, and 21%, respectively, of the total N fertilizer input to Chinese farmlands
during 2000–2003 (Wu et al. 2016). The amount of N fertilizer applied to maize
increased by 4% during 2008–2009, with a decrease in application on rice and wheat
(Wu et al. 2016). On average, the N application on wheat, maize, and rice increased
sharply from 45–60 kg N ha
À1 during 1970–1979 to 200–300 kg N ha
À1 in 2010
(Cui et al. 2014a; Wu et al. 2016). Additionally, the N fertilizer application rate of
wheat was higher in the North China Plain, while the highest N input rate of rice
occurred in Yangtze River region.
Furthermore, the cultivated land area of vegetables has increased nearly six times
from 1978 to 2011, resulting in a significant increase in vegetable production. The
vegetable planted area accounted for 12.1% of the total national crop-sown area in
2011 (National Bureau of Statistics of China 2016). Vegetable fields are often
characterized by intensive crop rotations (multiple harvests within a single year);
thus, more N fertilizer is applied to vegetables compared to maize, wheat, and rice.
For example, the average annual N input including both chemical fertilizers and
manure was 3239 kg N ha
À1 in some vegetable greenhouses in northern China
(Ju et al. 2006). Our results (Ti et al. 2015) showed that total N input in vegetable
cropping system in 2010 was 8.04 Tg N year
À1 . Chemical fertilizer N input in the
greenhouse system (478 kg N ha
À1 per season) was much higher than that in the
open-air system (201 kg N ha
À1 per season).
Fruits and tea also consumed a large amount of N fertilizer. Nitrogen applied to
fruit and tea farmland accounted for 13% and 17% of the total N input on Chinese
farmland during the 2000–2003 and 2008–2009 periods, respectively. The rate of
chemical N fertilizer use on conventional fruit and tea farmland was 330 and
536 kg N ha
À1 , respectively, which was much higher than that of maize, rice, and
wheat (Meng et al. 2017). Overall, compared to other regions/countries, such as the
USA and the EU, N use in China’s agricultural systems is much higher (Zhang et al.
2015).
13 Nitrogen Regulation in China’s Agricultural Systems
301