Geoscience Reference
In-Depth Information
Fig. 2.8 Decline in nitrogen
by percentage of soil and
years of cropping in several
case studies of the Great
Plains (United States,
1870
-
1930). Source Cunfer
(
2004
, p. 546)
previously unbroken sod of the Great Plains (Fig.
2.8
). In order to compete with
these cereal imports embodied with the unpaid
'
'
mined, European
farmers were forced to further increase yields per unit of land. Thus, the
virtual soil
rst
globalization linked an unsustainable extensive cropping system on one side of the
Atlantic, with an increasingly unsustainable intensive farming on the other.
Eventually, this double-sided process led to an agro-ecological and an economic
nal crisis of the two sorts of
'
advanced organic agricultures
'
. As Geoff Cunfer has
explained, referring to the case of Rooks County in Kansas:
By the late nineteenth
century, farmers had pushed into the upper Midwest, the Great Plains, and the
Paci
“
c Northwest. In the early twentieth century, only California remained to be
tapped for agriculture. The slow wave of westward plowing left behind a secondary
wave of abandoned farms. Farmers adopted the old Indian system of swidden
agriculture to solve the fertility dilemma. Traditional American farming relied on
the existence of an ever-new frontier. Played-out
elds eventually grew back to
forest or became low-intensity pasturage. Thus, it is no surprise that when the latest
wave of American farmers rolled into western Kansas in the 1870s, they imple-
mented a farm system that mined soil nutrients. They applied manure as it was
available and occasionally rotated legume crops when convenient, but they had no
strategy to sustain cropping for the long term. By the 1930s, Rooks County
elds
had been planted, cultivated, and harvested 60 times without rest. Soil nitrogen was
about half what it had been at sod breaking, and crop yields were declining steadily.
Moreover, the western frontier had disappeared. All of the arable land in Rooks
'
s
