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Living on the edge-the arid plains
Dryland ecosystems are characterized by extreme rainfall variability, recurrent
but unpredictable droughts, high temperatures, low soil fertility, high
salinity, grazing pressure, and fires. They reflect and absorb solar radiation,
maintain balance in the functioning of the atmosphere, and sustain biomass and
biodiversity. Although the biodiversity of drylands is low relative to that of
forests or wetlands, the ecosystem services they provide are considerable.
Despite its fragility the Serengeti Plain of East Africa currently supports the
largest tonnage of animal wildlife assembled on land, as did the equally
fragile Great Plains of North America in the past. Dryland species and
ecosystems have developed an array of coping mechanisms that provide resilience
and recovery in case of fire, drought, and pressure from wildlife. These
mechanisms are important for climate changes, which are expected to intensify
drought and the variability of rainfall in Africa.6
Of the 500 million rural people on arid and dry semi-arid land,7
most are in Asia and Africa, but there are also large pockets in Mexico and
Northeastern Brazil (figure 4.2). The low volume and
extreme variability of precipitation limit the productive potential of this
land for settled farming and nomadic
pastoralism . Many ways of expanding agricultural production in the
drylands-shifting cultivation from other areas, reducing fallow periods,
switching farming practices, overgrazing pasture areas, cutting trees for
fuelwood-result in greater environmental degradation.
Both state-driven and market-driven agricultural investments neglect dryland
agriculture, with its lower returns and higher risks, concentrating instead on
agriculture in more productive areas. Research and development (R&D)
funding for temperate agriculture is 70 percent of total public and private
funding for agricultural research. R&D funding for tropical agriculture
accounts for 28 percent of the total (mostly on rice). And R&D that focuses
on the problems facing people on fragile lands accounts for only 7 to 8 percent
of total R&D funding.8
Without the capacity to migrate, and without major financial and technical
support, poor rural inhabitants in arid areas have few prospects for meeting
their nutritional needs.9
The Southern Plains of North America, Africa's Sahel, and the inner Asian
grasslands face similar climatic and soil characteristics but different
political, financial, and institutional constraints. The case of the Southern
Plains is an example of the dismissal of indigenous knowledge followed by its
recognition, the near-extinction of the plains bison and subsequent efforts to
preserve it, the partial understanding of climatic variability followed by
technology to neutralize many of the effects of climate, and poverty followed
by massive outmigration and measures to expand the resilience of the ecosystem
to withstand drought and generate wealth (box 4.1).
Box 4.1
From degrading soils to degrading water-managing natural assets on the Southern
Plains
Many indigenous people in the Southern Plains of North America and around the
world recognized and accepted the basic constraints of drylands that forced a
pattern of ecological restraint on their behavior. They also designed rules to
alter destructive behavior. Complex and evolving institutions-traditions,
rules, laws, habits, and a conservation ethic-guided indigenous cultures to
conserve scarce natural resources and to survive in hostile environments by
getting the incentives right. The colonial settlers on the Southern Plains saw
the traditional use of productive land by nomadic groups as inefficient. They
converted prime grazing land into intensive agricultural uses (monocropping,
usually wheat). This pattern was badly suited to the lighter soils of the
Southern Plains. Deep plowing dislodged soils, and monocropping mined soil
nutrients.
Degradation, poverty, and migration
Large-scale farming in the 1920s pushed the expansion of wheat cultivation
further onto native grasslands. By the next decade overgrazing, overplowing,
and monocropping were exacerbated by the worst drought in U.S. history. An area
of about 50 million hectares was affected each year in the "Dust Bowl" of the
1930s. The government mobilized a range of experts to find
solutions-scientists, agronomists, civil engineers, political and social
historians, local farmers, businessmen, and politicians. The scientists'
solution was to bring back indigenous methods of planting a variety of plant
species, replanting grass on the looser soils, and limiting grazing. The
business view was against giving up the profitability and ease of monocropping
wheat on large farms. While hundreds of thousands of destitute people migrated
out of the area, the New Deal Conservation program spent an estimated $500
million on drought relief in the 1930s ($6 billion in 2000 dollars) and
introduced a series of measures:
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Federal Emergency Relief, zoning laws for the most fragile areas, repurchases
of submarginal private land (it was deemed easier to buy problem areas and move
the people living there to better land than to regulate and rehabilitate lands
under private ownership), cash payments for leaving land fallow, and farm loans
tied to approved land practices;
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The Civilian Conservation Corps, planting of shelterbelts with 220 million
trees, soil and water conservation techniques such as the introduction of
contour plowing, small dam and pond construction, mixed cropping, replanting of
grasses, and state and federal protection of the remaining open grasslands
under the Bureau of Land Management.
Beginning in 1940, normal rainfall patterns resumed, and outmigration reduced
the farm population and increased farm sizes (about 1 million people migrated
out of the area between 1930 and 1970). But in the 1950s Dust Bowl II hit,
followed in the 1970s by Dust Bowl III. Conservation practices had helped, but
to achieve reliable production for the agroprocessing industry, the United
States needed to achieve a "climate-free" agriculture on the plains. It needed
to get rain by pumping from deep, underground aquifers.
Financial transfers, technology, and "underground" rain
The government responded with an unprecedented and sustained political and
financial commitment at the national and local level to address the human and
environmental impact of degradation. The strategy reflected the conviction that
ingenuity and technology must solve the puzzles of nature that our ancestors
learned to live with as immutable forces. One striking feature has been the
reliance on fossil fuel-intensive agricultural production with deep pumping of
underground aquifers (up to 600 feet), and heavy reliance on chemical
fertilizers and mechanization. The vast aquifer is being pumped faster than
replenishment rates, with a net depletion rate of 3.62 million acre-feet (4.5
billion cubic meters) a year. Government net spending per head in the Southern
Plains is higher than anywhere else in the United States, with state farm
subsidies estimated at a cumulative $350 billion from 1960 to 2000.*
*The Economist (2002) December 15th.
Source: Worster (1979)
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It is also an example of a heavily subsidized, energy-intensive model that is
unlikely to be sustainable in the United States, and is not replicable in other
grassland regions. Few countries are of continental size, enabling easier
outmigration to better-endowed areas. Few economies are large enough or
diversified enough to enable extensive cross-subsidization from other sectors
to pay for the technical solutions to the problems of the fragile grasslands.
And few have the political and financial commitment to sustain such a high
level of support over such a long period. The solution to preventing and
offsetting Dust Bowl consequences required massive transfers from the rest of
society. Each affected state alone could not have solved the problems with only
its own resources.
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