Sauer - 1993 - Historical geography of crop plants, a select rost

210 Historical Geography of Crop Plants: A Select Roster
For thousands of years, the positive feedback between expanding rice
production and expanding human population has been continuous and is accelerating.
The population of Asia includes most of the world’s people and
has more than doubled in the last 40 years. The main reason the billions of
people in Asia are not starving is the phenomenal productivity they have
achieved in wet rice cultivation. Other crops, including introductions from the
New World, have helped, of course, as noted in other sections, but rice remains
basic. Asia was blessed with great mountains and heavy monsoon rains that
supply the meters of water required to grow each crop of wet rice. But it was
work and skill that created artificial marshes with controlled water flows and
managed nutrient cycles, Organic manuring and nitrogen fixing bacteria are
crucial parts of the artificial aquatic ecosystem. In some regions, water ferns
with symbiotic cyanobacteria are maintained in the rice fields. Commonly
ducks and fish, which helped control mosquitoes, were harvested along with
the rice. Where the climate allowed, two or three crops are grown each year.
Tight control of the artificial marshes and their water budgets may have been
developed earlier in temperate East Asia than in rice’s tropical homelands. In
tropical Southeast Asia and the East Indies, until the late 19th century, human
population and wet rice acreage were only a small fraction of what they are
today. Modern engineering projects to control water flow in the great floodplains,
deltas, and coastal swamplands have greatly expanded wet rice cultivation.
During the present century, every generation has added millions of
hectares of rice fields and tens of millions of humans.
A significant part of the increasing harvest of O. sativa in Asia during the
present century is due to scientific breeding. A key element in such breeding
has been the bringing together and hybridizing of formerly geographically
separated races. The breeders have been fortunate in having a heritage of
thousands of local varieties or landraces, the product of long evolution under
selection by farmers and by environmental variables. These largely self-pollinated
and inbred races provided the raw material for rapid yield increases
by genetic recombination in new hybrids. Japan was the first country to embark
on rice breeding by technical experts. Following the Meiji Restoration of 1868,
the central government established agricultural research stations in different
regions of Japan. These stations colleeted thousands of samples of farmer-bred
landraces, mostly domestic but a few from abroad. Following comparative
trials and classification, selection of pure lines and controlled hybridization
were begun. By 1925, most of the paddy rice planted in Japan consisted of
the new varieties, and the takeoff in yield was well underway. By the 1930s,
Japanese rice yields per hectare were approximately double their late 19th
century yields and triple the overall Asian average. This was accomplished
without changing the traditional pattern of labor-intensive small farms. In fact,
the average size of Japanese rice farms was declining to less than 1 ha. These
farms did adopt one western-style innovation, the use of synthetic nitrogen
fertilizer. Japanese rice breeders were aware early on that they needed to
develop new varieties that did not grow too tall and lodge, i.e., fall over when