ARTICLE BY MARCELLOUS LE ROUX
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Department of Agronomy (Faculty of AgriSciences)
University of Stellenbosch
“Soil is a living ecosystem, and is a farmer's most precious asset. A farmer's
productive capacity is directly related to the health of his or her soil.” Howard Warren Buffett
S
ince contemporary agriculture emanates from the
Industrial Revolution, it
shares goals of maximizing
productivity, economic return and
efficiency. It is recognized that the
most pivotal component of farming
systems is the soil itself and agronomic practices are innately linked
to the presence or absence of soil
organisms. The nature of the underlying organic matter (also referred
to as humus) and mineral components are not the sole drivers of the
composition of the soil biota component. On the contrary, the latter
is also strongly influenced by environmental variables such as temperature, pH and moisture. Numbers
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and types of soil organisms, especially microorganisms that are the
most abundant constituents of the
soil biota, are in a constant state of
fluctuation and are greatly influenced by agricultural activities such
as tillage and cropping practices.
Consequently, agricultural production combines practices and management suites that enhance crop
water- and nutrient acquisition, and
that minimize or completely eliminate weeds and crop diseases. However, production efficiencies of
most of the current agroecosystems are precariously poor
and widespread negative impacts
have been reported, including soil
erosion, loss of wetlands, deforesta-
tion, pollution of ground and surface waters caused by herbicides,
insecticides, and fungicides, as well
as eutrophication of estuaries
caused by off-farm movement of
excess nutrients.
It is apparent that the natural soil
balance, which hinges on biological,
physical and chemical components,
has been compromised over the
years with efforts of soil restoration
mainly being concentrated on the
latter two of these aforementioned
aspects. The presence and activities
of beneficial microorganisms in
conventional agricultural systems
have been neglected in favor of
non-sustainable inputs of energy,