Chemistry Reference
In-Depth Information
literature. However, evidence that this discussion has produced positive
impacts on either agriculture or the stability of the Earth system is scant at
best. Indeed, many negative trends, such as the loss of agricultural lands to
urbanisation and degradation of soils in agricultural regions continues
4-7
and
have dramatically accelerated agricultural policymaking since the sustain-
ability debate emerged.
Overall, while sustainability is an inherently vague concept whose scientific
definition and measurement lack broad agreement,
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virtually any accepted
definition includes the recognition that sustainable practices protect future
generations' access to essential ecosystems goods and services. Although
'sustainability' is widely used in economic and development contexts, here we
will emphasise 'sustainability' in its biophysical and ecological context, with an
emphasis on the sustainability of soil resources for agricultural production. In
past decades, a plethora of definitions of sustainable land management has
been produced.
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Some have been very lengthy, but, in essence, a biophysical
definition of sustainability refers to the combination of production and
conservation of the natural resources on which the production depends.
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Furthermore, sustainable agricultural production should not release any
products that make the environment less desirable for human occupation and
which cannot readily be removed.
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In a wider sense, agricultural sustainability
will be realised in a system that provides nutritional security and a healthy diet
for all under conditions that will allow us to continue to meet these demands in
the future.
The soil is the most important component in sustainable land management,
which has been indicated by pedologists, soil fertility experts and soil
biologists.
11-13
Sustainable land management is deemed necessary for both
the developed world, where high external input agriculture dominates, and for
the less developed countries, where the agricultural production is locally
dominated by low yields, little or no nutrient inputs, and inadequate soil
conservation practices. Sustainability problems occur through under-use of
resources (soil degradation) or over-use of resources (environmental effects of
nutrients and pesticides). Crop yields are key indicators for assessing
sustainable land management, but other indicators, as well as the determi-
nation of threshold values at which crop productivity is affected, are also
important.
Every approach to the challenge of describing and defining sustainable
agriculture has included soil characteristics and management in one way or
another. Because of the intersection of soils and sustainable agriculture, we
have undertaken a review of the ways in which soils are currently reflected in
sustainability reporting as applied to agriculture and food systems. In three
sections, we review the ways in which a number of major agricultural
sustainability initiatives that include both practice-based approaches (where
specific practices are required to meet the standard) and metrics-based
approaches (where producers implement their choice of best management
practices in order to meet specific outcomes) address soil management. Firstly,
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