Ráðunautafundur - 15.02.2001, Blaðsíða 31

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Comparison of bird populations on organic and conventional farms (Chamberlain et al. 1999)
surveyed over thrce breeding seasons indicated a higher species diversity on organic farms.
However it was concluded that habitat structure was the rnost important factor affecting bird
density not farming type per se.
Carabid beetles are considered of bioindicative value for assessing cultivation impacts
and changes in habitat quality. A recent review (Kromp 1999) concluded that Carabid beetle
numbers were enhanced by organic fertilization and green manuring. Again, an important
factor in increased numbers was crop diversity, presence of weeds and field boundaries. Cobb
et al. (1999) compared conventional farming with organic farming undergoing conversion
and concluded that organic practices can result in biodiversity gains for both plant and inver-
tebrate communities. Low-input and organic farming systems also encourage plants, in a
range of crops, to produce greater root length and colonisation of root systems by arbuscular
mycorrhizae (Mader et al. 2000). This indicates that organic systems may be more efficient in
performing a variety of ecological services beyond the production of food, including recy-
cling of nutrients, regulation of microclimate, regulation of hydrological processes, suppres-
sion of undesirable organisms and the enhanced potential to detoxify noxious chemicals
(Altieri 1999).
In 1988 Rhone-Poulenc agriculture commenced a long term study comparing conven-
tional and organic fann systems producing field crops such as vvheat and beans. This study
was extended in 1994 to include an ICMS treatment. The study has many independent col-
laborators investigating environmental, ecological and agronomic impacts of the tlnee re-
gimes. The ICMS demonstrates a consistent increase in profitability of 2CM0% over the con-
ventional system without loss of yield . Even though the organic systern constantly produced
lowcr wheat yields (40-50%) the premium associated with the product made organic wheat
the most profitable crop. However, the overall performance of the organic system was limited
by fertility breaks. Historically, adjusted gross margins frorn the three regimes showed that
the highest income was generatcd bv the conventional system, frorn 1990 to 1994, (this was
prior to ICM being included in the studv), the ICMS in 1995 and the organic regime from
1996 to 1998. Latterly this has been achieved by a high market demand that maintained a
scarcity premium for organic wheats, despite a vield that was 50% less than those from the
other systems.
Not all organic systems engender such yield penalties. A recent study at The Institute of
Grassland and Enviromnental Research on organic rnilk production found that grassland pro-
duction fell by 15% in the first year of conversion, but returned to pre-conversion levels as
clover became established. However, in common with other studies (Svensson et al. 2000),
the animals showed an increased incidence of health problems (Weller and Bowling 2000).
The livestock industry of Wales, and indeed the UK, cannot compete at world prices with
the big producers such as South America. due to higher costs of production. Thus we have to
generate a product with some sort of added value. Products from "naturaT grass-based sys-
tems that are constructed to enhance the bio-diversity of the countryside and the use of native
breeds will have roles to play in the future. Many outstanding areas of natural beauty exist
within Wales and it will become increasingly important to link the product and process. It
should be possible to market agricultural products from the Site of Special Scientifíc Interest
(SSSI) to the Biosphere scale but this will require a high degree of product traceability.
There is little direct evidence that the agricultural product (meat) from these schemes dif-
fers in any fundamental way. However, the UK Department of Health has recommended an
increase in the intake of unsaturated acids such as omega-3 polyunsaturated fatty acids