Agriculture Reference
In-Depth Information
Bioengineering of food crops, large-scale international land acquisitions, and shifts in
crops to biofuel production are just a few examples of management that will need to be
reassessed under interacting global changes. Reduced levels of applied chemicals such as
herbicides, fertilizers, and pesticides that were often nonrenewable and toxic and produced
externally can now be combined with the use of biocontrol (e.g., parasites, predator-pest
interactions) in trials to manipulate belowground diversity for enhanced plant production.
Increasing knowledge of these and other new options for managing agriculture and con-
nected ecosystems sustainably must include belowground diversity as a component if we
are to discover new longer-term, larger-scale strategies and avoid ecosystem surprises and
further degradation of ecosystems (MA, 2005; Clark, 2007).
The earliest farmers and hunters practiced sustainable land management, although
they may not have been aware of the multiple organisms interacting in soils. Management
of soil was known to be an important link to production of food, although there is also a
history of civilizations declining because of inattention or abuse of soil. This long history
of human involvement in agriculture was primarily at small scales (compared to current
large-scale land-use change). Since the advent of cheaper chemical inputs, many have not
considered management of soil biodiversity as linked to sustainability of human popula-
tions and to the overall global picture of growing populations and food demand. However,
in the past 30 to 40 years, numerous international agreements, policies, and scientific con-
sensus reports have documented results that together show that for environmental sus-
tainability to occur, soil biodiversity must be considered as part of soil productivity, not
ignored or left out of discussions on the flows, properties, and connections of global cycles.
A few examples of environmental issues, global assessments, and policy agreements that
directly involve soils as critical components show that inclusion of more information on
soils and soil biodiversity can be valuable for environmental management and long-term
provision of ecosystem services.
The Montreal Protocol is one of the most famous agreements known for its success in
galvanizing nations toward a common solution. It is, however, an example of misun-
derstanding the magnitude of connections between the atmosphere and belowground-
aboveground conditions. The 1995 Montreal Protocol on Substances that Deplete the
Ozone Layer required a phaseout of certain halogenated hydrocarbons, including the soil
fumigant methyl bromide. This compound is used globally in agricultural forestry and
produce to suppress soil pest sand pathogens (such as species of fungi, nematodes, insects,
mites, rodents, weeds, and some bacteria) and to enhance root health, plant growth, and
yield. But, it also has broad soil biocidal activity affecting nontarget organisms, including
beneficial organisms (Nyczepir and Thomas, 2009). Methyl bromide emissions account for
about 5-10% of global stratospheric ozone depletion, and although being phased out since
2005 in the United States, exemptions exist for many crops and countries (Schneider et al.,
2003). Today, as a result of the Montreal Protocol, and a new awareness of the impact of
pesticides, many alternatives to methyl bromide are being tested, including solarization
of soils, pathogen-resistant crop varieties, methyl iodide, and other less-ozone-depleting
pesticides. While these alternatives meet the criterion of not harming the ozone layer, they
are evaluated for additional effects, such as toxicity problems for water and effects on
soil food webs, nontarget organisms, and humans (Ingham and Coleman, 1984; Duniway,
2002; Sanchez-Moreno et al., 2009, 2010). It is doubtful that the food production needed for
tomorrow's populations can be reached in larger-scale agriculture without fertilizers and
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