Book Review: Darwinian Agriculture

jpegSeems like these days, every enviro-minded, hippie-dippie, socially-conscious-consumer has an opinion about organic farming,  farm animal welfare and GMOs. But how much do we really know about this big field that is agricultural science?

Turns out, even the most knowledgeable food scientists might not know it all. I was amazed to find out that many researchers forget to consider Darwin’s theory of evolution in their practice. Wait a minute … genetics is the basis of crop science. How can this be ignored?

R. Ford Denison is a professor of ecology, evolution and behavior, plant biological sciences at the University of Minnesota, and was the director of the Long Term Research on Agricultural Systems (LTRAS) project. He wants his readers to know that every agricultural researcher from biotechnologist to ecologist should pay more attention to evolution principles in their practice, and he underpins his arguments with an incredible wealth of insights from 380+ citations. Let me give you the highlights.

The stakes

The main challenge of today’s agriculture is to feed 9 billion by 2050 while preserving rainforest, biodiversity, soil and water. In my opinion, better distribution and reducing food waste (great video here) is a priority, but beyond the scope of this book. For agriculture, this means that we need to produce more with less land and with less water … in other words, we need a better yield.

Two approaches have been proposed to meet the goal of feeding 9 billion: biotechnology and alternative agriculture that mimics nature.

Bio-photo-from-iStock-small    farm-fieldbeds-350
VS.

Theory of Evolution 101

The basic idea is that each living thing (plant, insect, bacteria, fungus…) will evolve genetically to better fit the environmental conditions they live in. Mutation and reproduction are the two ways genetic material can evolve. Then organisms adapted to the environment will survive/grow taller/reproduce more that the less adapted ones. This is what’s called natural selection. Although the theory doesn’t really work for humans anymore…

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credits: Barry Hoare

Biotechnology

While Denison is not against biotechnology, he warns that the many of the crops developed by biotechnology today are only short-term solutions that ignore evolutionary trade-offs. They are designed to win competition with weeds and pests. However, pests are genetically very adaptive, they will take just a few years to develop resistance. Denison argues that natural selection is fast enough and has improved plants for long enough that it has left few simple, trade-off free opportunities for future genetic improvement. He writes: “the potential risks of biotechnology – real and imaginary – has received much more attention than the failure to deliver on some key promises” and also “biotechnology is unlikely to deliver soon on some key promises, such as crop that yield more grain while using less water”.

Copying natural ecosystems

I’m one of those who think that ecological farming mimicking natural ecosystems is the way to go … but again Denison shows that this way of thinking ignores evolutionary principles. In an ecosystem, each organism evolves for their own survival and are only limited by the space and resources other organisms take. Plants will grow more leaves to shade their neighbours, grow deeper roots to access water first. Those strategies take resources that could otherwise be used to grow bigger grains/fruits/vegetables. So, natural ecosystems are unfortunately not organized to optimize yield. But don’t get me wrong, they are great at preserving healthy soils, clean water, and they are vital to preserve biodiversity, providing the genetic variety that will allow agriculture to adapt to changing environmental conditions.

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credits: Dave Coverly

Solutions to increase agriculture’s productivity

That’s where the book gets a bit more technical and requires some solid background in genetics and plant metabolism … here’s a light, nutshell version.

  • Plain-old crop rotation: we can use polyculture designed to benefit from spatial, seasonal and nutritional complementary among species. Plus, crop rotation can help starve pests that like only one type of crop (they die when the plant it not grown, and the plant is grown again when all pests have gone). Denison suggests  planning diversity at coarse scales: landscape to planet!
  • Plant breeding to favour community performance rather than individual competitiveness: Natural selection would not favour those varieties, so there is room for improvement by human intervention.
  • Improving collaboration between species: There are lots of examples in nature that we could build on. Legumes are the most common examples. They enter in symbiotic collaboration with bacteria that absorb nitrogen from the atmosphere. Right now those collaborations are less productive as they could be – bacteria evolve to do the least work for the most benefit – but they could be optimized. I hope you like beans!
  • Slowing pest resistance: While resistance happens all the time in nature, and not only to pesticides, there are ways to slow the process. This involves collaboration between farmers to starve pests all at the same time, the creation of refuges for non-resistant pests, or the use of the pest predators.
  • Bet-hedging: the more crop options we have, the more we can be ready to our changing environment. We need genetic diversity, so we need to preserve diverse species and variety among species… that’s how we get to quinoa adapted to Ontario weather for example.

Heavy stuff. You’ve earned a comic strip break…

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Credits: Dan Reynolds

R. Ford Denison concludes that  we should really include evolution theory in all agriculture research, and spread our research dollars as wide as possible. Right now biotechnology gets the biggest buck while crop physiology, agroecology, traditional plant breeding, weed ecology and evolution, soil microbiology and agricultural entomology research are starved. He urges for collaboration between research disciplines. Historically, those collaborations have yield the best agricultural innovations.

Now, if you’ve made it this far, you must be an agro-enthousiast! If you want to dig deeper, I recommend the feeding 9 billion website, featuring plenty of videos by University of Guelph professor Evan Fraser. Here is one to start with:

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