Agriculture Reference
In-Depth Information
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Long-Term Ecological
Research at the Kellogg
Biological Station LTER Site
Conceptual and Experimental
Framework
G. Philip Robertson and Stephen K. Hamilton
Over half of the land area of the contiguous United States is in agricultural pro-
duction, with over half devoted to row crops such as corn (
Zea mays
L.), soybean
(
Glycine max
L.), and wheat (
Triticum aestivum
L.) (NASS 2013). These crop-
ping systems thus represent one of the most extensive and important ecosystem
types in North America. The vast majority of this cropland is managed intensively
with tillage, chemical fertilizers, and pesticides to achieve high yields. And with
well-known environmental impacts on soils, watersheds, surface and coastal
waters, and the atmosphere (Matson et al. 1997, Robertson et al. 2004, Robertson
and Vitousek 2009, Tilman et al. 2011), the environmental consequences of agri-
cultural intensification extend well beyond the boundaries of individual farm fields.
While the catalog of agriculture's harmful environmental impacts is extensive—
ranging from biogeochemical pollution to diminished biodiversity to human health
risks—many of the benefits are substantial, not the least of which is human well-being
from the provision of food and other products. Less well appreciated are agriculture's
contributions to a number of other ecosystem services (Swinton et al. 2007, Power
2010)—clean water, flood protection, climate regulation, disease and pest suppres-
sion, soil fertility, habitat conservation, and recreational and aesthetic amenities,
among others—all of which benefit people.
Also underappreciated is the degree to which agricultural ecosystems are linked
to one another and to unmanaged areas of the surrounding landscape such as surface
waters, wetlands, woodlots, and abandoned fields undergoing ecological succes-
sion. Only recently have we learned the importance of many of these understudied
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