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Thursday, 30 May, 2002, 18:23 GMT 19:23 UK
Organic farming 'a realistic choice'
Aerial view of plots   Science
The Swiss plots: The comparison began in 1978

After a 21-year study, Swiss scientists have given a ringing endorsement to organic farming methods.

They found organic yields were on average 20% smaller than those from conventional agriculture.

But the ecological benefits more than made up for this, and the organic crops proved more efficient users of energy and other resources.

The scientists conclude that organic production is a viable alternative to conventional ways of farming.

They are from the Research Institute of Organic Agriculture and the Swiss Federal Research Station for Agroecology and Agriculture. They report their findings in Science magazine.

The team, led by Paul Mader, compared plots of cropland grown according to both organic and conventional methods and planted with potatoes, barley, winter wheat, beet, and grass clover.

More from less

Crop rotation, varieties and tillage were identical in all the plots.

Over the study period, which began in 1978, they compared normal organic production, another organic approach called biodynamic farming, based on the work of Rudolph Steiner, and two conventional farming methods.

Mycorrhizae in plant roots   Science
Mycorrhizal structures in a plant root
One of these used mineral fertilisers and farmyard manure; the other did not use the manure.

Although organic yields averaged 20% less than those from the conventional plots, the input of fertiliser and energy was reduced by between 34% and 53%, and pesticide use by 97%.

Overall, the team found, the organic systems used resources more efficiently, producing more for each unit of energy and other inputs they consumed.

The scientists also found that the organic soils housed a larger and more diverse community of organisms.

These included soil microbes, which govern the nutrient cycling reactions in soils, and mycorrhizae, root-colonising fungi which help plants to absorb nutrients.

The researchers said the fungi were at least partly responsible for the more stable physical structure of the organic soils.

Insects were almost twice as abundant and more diverse on the organic plots. Species found included pest-eating spiders and beetles.

Earthworms were also more common, and the weed flora was more diverse, with some specialised and endangered species among those found.

Better breakdown

Paul Mader said: "These results should be encouraging for farmers, because they can see that yields are stable over time, and that soil fertility has increased.

"Our results suggest that, by enhancing soil fertility, organic farmers can help increase biodiversity."

Scientist measures wheat plants   Science
Assessing wheat growth in the field plots
The researchers also found that the organic soils decomposed more efficiently, releasing nutrients and carbon to be absorbed by plants and microbes.

They say: "The organic systems show efficient resource utilisation and enhanced floral and faunal diversity, features typical of mature systems.

"We conclude that organically manured, legume-based crop rotations utilising organic fertilisers from the farm itself are a realistic alternative to conventional farming systems."

Expensive interval

In the UK many farmers would like to switch from conventional chemically dependent farming.

Much organic food eaten here is imported because domestic production cannot supply the market, despite the higher prices organic products attract.

But the obstacle is very often the time that must elapse between abandoning the use of chemicals and being certified organic.

Without government help, it is an impossibly expensive gap for many farmers to cross.

Images copyright and courtesy of Science

See also:

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