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Organic farms have better fruit, study finds

September 7, 2010  By Fruit & Vegetable


September 7, 2010 –
Side-by-side comparisons of organic and conventional strawberry farms and their
fruit found the organic farms produced more flavourful and nutritious berries
while leaving the soil healthier and more genetically diverse.



September 7, 2010 –
Side-by-side comparisons of organic and conventional strawberry farms and their
fruit found the organic farms produced more flavourful and nutritious berries
while leaving the soil healthier and more genetically diverse.

“Our findings have global
implications and advance what we know about the sustainability benefits of
organic farming systems,” said John Reganold, Washington State University (WSU)
Regents professor of soil science and lead author of a paper published in the
peer-reviewed online journal, PLoS ONE. “We also show you can have high
quality, healthy produce without resorting to an arsenal of pesticides.”

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The study is among the
most comprehensive of its kind, analyzing 31 chemical and biological soil
properties, soil DNA, and the taste, nutrition and quality of three strawberry
varieties on more than two dozen commercial fields – 13 conventional and 13
organic.

“There is no paper in the
literature that comprehensively and quantitatively compares so many indices of
both food and soil quality at multiple sampling times on so many commercial
farms,” said Reganold. Previous studies of “sustainability indicators” on farms
in the Pacific Northwest, California, British Columbia, Australia, and New
Zealand have appeared in the journals Science, Nature, and Proceedings of the
National Academy of Sciences
.

All the farms in the
current study were in California, home to 90 per cent of the nation’s
strawberries and the center of an ongoing debate about the use of soil
fumigants. Conventional farms in the study used methyl bromide, which is to be
replaced by methyl iodide. In July, California Sen. Dianne Feinstein asked the
U.S. Environmental Protection Agency to reconsider its approval of methyl iodide.

Reganold’s study team included
Preston Andrews, a WSU associate professor of horticulture, and seven other
experts, mostly from WSU, to form a multidisciplinary team spanning
agroecology, soil science, microbial ecology, genetics, pomology, food science,
sensory science, and statistics. On almost every major indicator, they found
the organic fields and fruit were equal to or better than their conventional
counterparts.

Among their findings:

  • The organic strawberries
    had significantly higher antioxidant activity and concentrations of ascorbic
    acid and phenolic compounds.
  • The organic strawberries
    had longer shelf life.
  • The organic strawberries
    had more dry matter, or, “more strawberry in the strawberry.”
  • Anonymous testers, working
    at times under red light so the fruit colour would not bias them, found one
    variety of organic strawberries was sweeter, had better flavour, and once a
    white light was turned on, appearance. The testers judged the other two
    varieties to be similar.

The researchers also found
the organic soils excelled in a variety of key chemical and biological
properties, including carbon sequestration, nitrogen, microbial biomass, enzyme
activities, and micronutrients.

DNA analysis found the
organically managed soils had dramatically more total and unique genes and greater
genetic diversity, important measures of the soil’s resilience to stress and
ability to carry out essential processes.


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