Facts and Myths of Feeding the World with Organic Farming Methods - Principles of Sustainable Soil Management in Agroecosystems - page 98

Nitrogen Cereals

125 2500

100 2000

75 1500

50 1000

25 500

0
1920

0

1930 1940 1950 1960 1970

Year

1980 1990 2000 2010

FIGURE 4.2 Nitrogen fixed by Haber-Bosch process (Mt, left axis) and world production
of cereals (Mt, right axis). (N data from Smil, V., World Agric 2:9-1, 2011. Cereals data from
FAOSTAT. Food and Agriculture Organization of United Nations, Rome, 2012. Available at
http://faostat.fao.org , accessed April 3, 2012.)

World War II. During both World War I and World War II, the process was used to
make N for bombs. Following World War II, many of the facilities that made bombs
during the war were converted to N fertilizer plants, and this was the beginning of a
major expansion of the use of fertilizers. The data shown in Figure 4.2 clearly show
how closely cereal production has been linked with ammonia synthesis. Assuming
that the N concentration of cereals is 1.8%, there was about 45 Mt of N contained
in the cereals produced in 2010. Much, if not most, of this N will not be recycled
through the crop production system. Therefore, while synthetic N fertilizer appears
essential, some believe that the world's population can be fed without using N-based
fertilizers. Nielsen (2005) makes this argument and also believes that the problems
created by the use of synthetic fertilizers have outnumbered their benefits. He chal-
lenges two claims: (1) that the human-invented process of fixing nitrogen caused a
global population explosion, and (2) without nitrogen-based fertilizers, we would not
be able to feed the world. He points out that the population explosion was already
advanced and well on the way when nitrogen-based fertilizers were introduced, and
while the use of fertilizers may have supported the explosion, even this is doubt-
ful. Nielsen (2005) stated that the world could be fed without using N fertilizers.
He argued that this could be done by prudent organic farming, improving irriga-
tion efficiency, improving the environment for nitrogen-fixing organisms, healing
the soil that has been destroyed by using N-based fertilizers and other agricultural
chemicals, and changing our food consumption habits. Even if this is possible, it is
certainly not feasible because the reality is that the trends are in the opposite direc-
tion. In 1961, the number of calories per capita for the world population was 2201
compared to 2798 in 2007, and calories from meat were 110 and 218, respectively
(FAOSTAT 2012). A more striking example is China. In 1961, China was in a period
of famine, and the number of calories per person was only 1469, of which only 29