One thing we have learnt this week – organic farming

harvest finished in autumn_optThe BBC consumer programme  “You and Yours” was turned over to organic farming for a whole programme on Monday.  The programme looked at a variety of aspects of organics from a Danish and UK perspective.  Denmark was chosen since it has the highest proportion of organic food sold in the world.  In it I learnt something surprising.   Organic farming could improve crop yields.

The general thought is that yields of organic crops are lower than non-organic crops.  This is for a variety of reasons.  Firstly most crops with the exception of legumes have been bred (using classical methods) to require huge volumes of nitrogen based fertilizers (see past blog posts on this site).  This produces high yields but takes a lot of energy and at a large environmental cost.  A large part of the destruction of the Great Barrier reef is down agricultural run off, as well as climate change.  Soils are also being destroyed by excessive use of nitrogen based fertilizers.  Another reason for lower crop yields (and production of meat) is pests and diseases.

Imagine my surprise when one of a number of farmers interviewed who was embracing organic farming was doing so to raise yields.  This farmer grew wheat (needs loads of nitrogen) but his harvest had dropped from 3 tonnes/Ha to 1tonne/Ha.  The reason?  Lots of black grass in his wheat.  I’d not heard of this, although I do recognise it.  Its a common and attractive garden plant, although clearly a huge pest.  It turns out the best way to deal with it is organically.  Other farmers were switching for economic reasons, they take a hit on yields but get a higher price.

The programme also looked at the alleged health benefits (better nutrition) of organic food.  This is much more contentious and difficult to prove.  To prove this you need to grow exactly the same crop variety, in exactly the same soil, under exactly the same environmental conditions, harvest it at the same time and analysis the crops in the same lab using the same instrumentation and reagents at the same time (and I’ve probably missed something out).  As this can prove difficult even in the same field, few studies have been done.   There have been some studies that suggest that organic milk has a higher content of 3-ω-fatty acids, one of the two essential fatty acids we need but cannot make.  However it has a lower concentration of 6-ω-fatty acids (the other one) and its unclear how much milk has anyway of this fatty acid.  It not listed as one of the main sources.  On a follow up report on today’s programme more questions were asked about the health benefits of organic food.  There are some studies to suggest that some pesticides act as “gender benders”.  This site had a look at this regarding fracking.  This seems plausible to me since a very wide range of different compounds can act in this way.  I would also point out that so many pesticides are withdrawn from use due to safety concerns.

I buy organic food on occasions and grow organic food, but I would not get hung up on it.  Its more important to eat a balanced healthy diet with as local food as possible.  However having said that it seems crazy not to buy something that avoids a whole heap of problems and is not sustainable in the long term.


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