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Learning organic's dirty secrets
Posted Wednesday, August 27, 2008 8:41 AM
 
Martin Entz, pictured above, is a professor at the University of Manitoba's Department of Plant Science.

In 1992 Martin Entz started growing crops in an un-Western way to prove to himself that it couldn’t be done.

But after nearly 17 years of comparing organic and conventional agricultural practices at research farms around Winnipeg the plant scientist delightfully notes his assumptions were wrong.

The Glenlea long-term organic/conventional crop rotation study is Canada’s oldest and it’s providing valuable insights into natural farming systems.

A major finding pertains to soil health, specifically, the microorganisms living in it. (To re-cap from a first-year Biology course, over 95 per cent of vascular plants have fungi in their roots and this association benefits the plants in numerous ways.)

In Year 13, graduate student Cathy Welsh, working with Entz and soil sciences’ Mario Tenuta, compared the plots’ fungal spore density and diversity – a hallmark of soil health, and indirectly and to some degree, plant health. In short, the organic system was a metropolis compared to the conventional plot.

“It shouldn’t have been a surprise to find this, but it was,” said Entz, a University of Manitoba professor in plant science.

This has many implications, one of which pertains to fungal resignation.

Soil in conventional systems is obese with fertilizer-derived nutrients. This causes the plant, specifically those mycorrhizal fungi, to become lazy, which is a shame since they are superb micronutrient extractors. But in such systems they sit back and wait for fertilizers to bring the goods to them. They fail to extend their hyphae and the plant, as a result, ends up having a lower micronutrient density when compared to plants in organic plots.

So organic food not only has fewer pesticides on its exterior, but its interior hosts a gala of zinc, iron and the like. What’s more, when the plant is left to fend for itself its immune and other systems become more robust. Flax samples Entz took from his 1995 to 1999 crop years confirm this and a current project is further investigating it, as well as things like mill quality.

Another drawback to conventional farming is how much energy (read oil) it takes to cram nitrogen into fertilizer. Indeed, since about one-half of the energy on our dinner plate came from nitrogen, we are essentially eating oil, Entz notes.

To rectify this, he is experimenting with “green manure” – plants, like legumes, that extract nitrogen from the atmosphere. These plants then get mashed into the soil by way of a tractor add-on Entz’s lab created. The legumes soon decompose and cycle nitrogen into the soil.

All this sounds great, but everything seems to have a downside. A major flaw critics point to in organic systems concerns yields: you can’t, the argument goes, feed the world on organic.

“But that’s a premature debate,” Entz said, noting that less than one per cent of Canada’s land is now under organic cultivation. “The real debate needs to be on how we can achieve sustainable agriculture because our current system is not sustainable.  Also, we need to keep in mind that much of the world currently feeds itself using what are essentially organic methods”.

Besides, Entz notes, the gap in yields should close with further research. Currently, organic plots produce up to 85 per cent of the calories a similar conventional field can, but it takes 30% less energy to do so. And as Entz and others work with farmers to breed crops specifically for organic systems the yields will increase.

“Our current agricultural model is getting tired. It had a good run, but it’s time to adapt – that’s how civilizations move forward. What Glenlea offers us is a laboratory that lets us explore what these natural processes offer humanity. And what we learned is that they offer a ton.”

 
For more information, contact:
Sean Moore
Communications Officer
Marketing Communications Office
sean_moore@umanitoba.ca
Phone: (204) 474-7963
 
Related Links (Internal):
  •Department of Plant Science