Environmental Engineering Reference
In-Depth Information
total cultivated area in 1900. Even if the actual total were twice as large, it would
still be less than half the difference between the lowest (710 Mha) and the highest
(935 Mha) estimate of arable land for 1900 (HYDE 2011).
In contrast, the modern production of animal foods depends on concentrates,
that is, grains (mainly corn, but also wheat and barley) and tubers (cassava, pota-
toes) as source of carbohydrates, and soybeans as the high-protein ingredient (sup-
plemented by oilseed cakes and by various crop and food-processing residues). Most
of the cropland in afl uent countries is now devoted to growing feed rather than
food: during the i rst decade of the twenty-i rst century nearly 60% of U.S. farmland
was used to grow corn, soybeans, hay, and sorghum, the four leading feed crops
(USDA 2009). Increasing animal food intakes in land-poor countries could be done
only by expanding imports.
In Japan, the world's largest food importer, feed corn became the country's most
important imported grain during the late 1960s, when it surpassed imports of wheat
for food consumption. Recent annual corn imports have been around 16 Mt/year,
or more than 6% of America's corn crop, and their production required about 1.8
Mha, an equivalent of nearly 40% of Japan's arable land. Less than 10% of the
imported wheat is used as animal feed, but barley imports are about equally split
between food and feed uses, and sorghum, the fourth largest imported grain, is used
only for feeding. In total, by the year 2000 Japan's feed grain imports had reached
27 Mt, by far the largest in the world and equal to almost exactly 10% of the global
cereal trade.
And more land was claimed by feed grown to be produced Japan's meat imports.
After decades of protectionist measures the country began to opens its meat market
during the late 1980s, and the imports rose from about 0.7 Mt in 1985 to almost
2.8 Mt by the year 2000, making Japan the world's largest buyer of meat. In addi-
tion, Japan has been an importer of dairy products and eggs, amounting to alto-
gether more than 600,000 t of animal protein imported in the year 2000. The
average yield of all animal protein was about 200 kg/ha, implying a total land claim
of about 3 Mha to produce feed for the export of animal foods to Japan (Smil and
Kobayashi 2012). Alternative calculation methods yield similar totals, between 2.5
and 3.5 Mha for the year 2000 (Galloway et al. 2007).
Calculations of global feed requirements for the year 2000 show an enormous
increase in phytomass claimed by the production of animal foodstuffs. In that year
the total number of large animals approached 1.6 billion, including 1.3 billion heads
of cattle, 164 million water buffaloes, 70 million horses and mules, more than 20
million camels, 900 million pigs, and 1.75 billion sheep and goats (FAO 2011c).
