Grasslands of the World.pdf - Disasters and Conflicts - UNEP

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Grasslands of the world
PASTORAL AND AGRICULTURAL SYSTEMS
Considerable portions of the central grasslands of the USA have been converted
to intensive agriculture (Gunderson, 1981). Thomas, Herbel and Miller (1990)
estimated that only about 1 percent of the original tall-grass prairie is still in
native vegetation , while Lauenroth, Burke and Gutmann (1999) estimated that
approximately 50 percent of the short-grass prairie is still uncultivated.
Crop production
Wheat is the major crop grown on the western edge of the Great Plains,
although larger percentages of the land in wheat occurred in central and eastern
Kansas and Oklahoma and northeastern North Dakota (Lauenroth, Burke and
Gutmann, 1999). The pattern of acreage of wheat grown in the Great Plains
was one of breaking native sod during times of plentiful precipitation and high
wheat prices, and abandonment of these lands during drought and periods of
low wheat prices (Holechek, Pieper and Herbel, 2001; Sims, 1988; Stoddart,
Smith and Box, 1975). The dust bowl of the 1930s occurred in southeastern
Colorado, southeastern Kansas and the Texas and Oklahoma panhandles,
largely on land unsuited for cultivation without irrigation (Costello, 1944;
Holechek, Pieper and Herbel, 2001; Jordan , 1995; Sims, 1988). Considerable
effort has been expended in developing seeding techniques to “recover” these
abandoned fields (Bement et al., 1965).
In 1985, the Food Security Act provided the opportunity for land owners to
retire cropland, and provided cost-share funding to establish grass cover, wildlife
habitat or trees (Joyce, 1989). Under the Conservation Reserve Programme
(CRP ) of this USA Act, many land owners converted cropland to grassland
(Mitchell, 2000). The CRP is a voluntary cropland retirement programme
under which the Federal Government pays an annual rental fee and a cost
share for conversion from cropland to a permanent cover of grass, wildlife or
trees. The basic goals for creation of the CPR were to: (1) take highly erosive
cropland out of production and to establish a permanent perennial vegetation
cover; (2) to decrease farm commodity surpluses; (3) to generate stable
incomes for participants; and (4) to enhance natural resource values, including
soil, water, air quality and wildlife (Goetz, 1989; Heimlich and Kula, 1989).
The map presented by Mitchell (2000) shows that CRP lands are concentrated
in the plains states, with high densities in the northern Great Plains (Montana
and North Dakota), the corn belt (southern Iowa and northern Missouri) and
the southern Great Plains (eastern Colorado, western Kansas and the panhandles
of Oklahoma and Texas). Originally, the CRP programme was designed
for a 10–15-year period, but in separate Acts in 1990 and 1996, the CRP was
extended and broadened (Mitchell, 2000).
Most land in the Great Plains is under private ownership (Holechek, Pieper
and Herbel, 2001). For example, Neubauer (1963) reported that there was
nearly 34 million hectares of private range and pasture land in the Dakotas,