Agriculture Reference
In-Depth Information
Fig. 1.1
Five decades of
world crop production: 1960-
2010 (Gross Production
Index Number (2004-2006 =
100). (Source: FAOStat 2011)
not economical, or increasingly likely to cause irreversible environmental impacts,
such as species extinction and climate change (Tilman et al.
2002
). Climate change,
moreover, threatens to further complicate the challenge of a sustainable increase in
agricultural production—given increasing temperatures, shifting rainfall patterns,
increasing variability, and greater frequency and severity of extreme weather events.
Such Malthusian views, however, are based on a linear conception of agricul-
tural productivity growth and a static conceptualization of the nature of resource
constraints. In the long run, the resource-use efficiency of agricultural production—
the amount of land and water required per ton of harvested yield—has proven to be
quite dynamic, and has improved markedly when measured over decades (Alston
et al.
2010
). Constraints of land or water use shift and recede before changes in
technology, cropping, and cultural practices. Productivity growth is driven by sev-
eral factors, and the most important include: (i) The quantity and the quality of
the natural capital employed, particularly land and water, (ii) other physical capital
employed, including mechanical equipment and irrigation infrastructure, (iii) suit-
ability of other inputs and technologies employed, such as fertilization and pest
control, (iv) the genetic traits and yield potential of the crops sown, and, finally, (v)
the efficiency of allocations of agricultural inputs and outputs under the manage-
ment of farmers and in response to price signals from markets. Moreover, all these
factors can interact in complex, sometimes mutually reinforcing ways to improve
agricultural productivity and, ultimately, its sustainability.
Of these factors, one of the potentially most significant for future increase in
productivity will be the genetic improvement of crops to maintain yields under
suboptimal conditions—such as drought or chronic water deficit, excessive salinity,
extreme hot or cold temperatures, or other kinds of environmental stress or abiotic
stress (Araus et al.
2008
). Such conditions characterize—indeed, they define—
those lands that are considered to be 'marginal', whether currently cultivated lands
achieving lower and unstable yields or currently uncultivated lands, including those
abandoned due to soil degradation by previous agricultural practices. Such yield-
