New Zealand Journal of Agricultural Research abstracts
A comparison of soil and environmental quality under organic and conventional
farming systems in New Zealand
L. M. CONDRON
K. C. CAMERON
H. J. DI
T. J. CLOUGH
E. A. FORBES
R. G. MCLAREN
R. G. SILVA
Centre for Soil and Environmental Quality
P.O. Box 84
Lincoln University
Canterbury, New Zealand
Abstract Organic farming in its various forms is seen by many
as a sustainable alternative to conventional farming. This review considers and
compares aspects of soil and environmental quality associated with organic and
conventional farming systems under New Zealand conditions. The sustainability
parameters considered include soil quality, nutrient dynamics, nutrient
budgets, trace elements, and pesticides. The review used information from
appropriate comparative studies conducted in New Zealand and overseas. However,
because of the shortage of data on nutrient dynamics under organic systems in
New Zealand, we also used a nutrient balance model (OVERSEER) and a nitrogen
leaching estimation model to assess the comparative sustainability of typical
model systems. Interpretation of the measured data coupled with the results of
the modelling exercise suggests that organic farming carried out according to
the Bio-Gro New Zealand production standards can be sustainable if sufficient
amounts of nutrient are returned to match removal and losses. Biodynamic
farming may be unsustainable because nutrients removed in farm produce are not
adequately replaced. Soil organic matter content and biological activity is
generally higher under both types of organic system than under conventional
systems. Trace element availability and use may limit the sustainability of
organic systems if no attempt is made to address natural deficiencies common in
New Zealand soils. The reduced use of pesticides may be beneficial for the
wider environment. The main conclusion is that a concerted research effort is
urgently required to address various soil and environmental quality issues
associated with the large-scale adoption of organic farming practices in New
Zealand.
Keywords soil quality; organic farming; Bio-Gro; conventional
farming; nutrient cycling; trace elements; heavy metals; pesticides;
sustainability; biodynamics; environment
New Zealand Journal of Agricultural Research, 2000, Vol. 43: 443-466
0028-8233/00/4304-0443 $7.00/0 (c) The Royal Society of New Zealand
2000
PDF file of entire paper: medium quality (1913K); (scanned from paper original: notes about this process)
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