Recently in Talks by Ford Denison Category

Jeremy Cherfas recently interviewed me on Eat This Podcast, which has many interesting food- and agriculture-related interviews.

Earlier, Cherfas cofounded my favorite blog, the Agricultural Diversity Weblog, so I was delighted when he was the first to review my book. My book argues that crop rotation (with both crop diversity over time and lanscape-scale spatial diversity) often makes more sense than crop diversity within a field (intercropping). Jeremy's mostly-positive review points out that I neglected to discuss diversity within a species, such as growing a mixture of two or more wheat varieties. So I talk about that some in the podcast interview.

But in asking "how should we deploy crop diversity in space and time" both book and podcast implicitly assume that total usable diversity is limited. If there are currently only two wheat varieties that can be grown profitably in a given region, you have to choose between growing the same two-variety mixture every time you grow wheat, versus rotating (alternating) between them. (Growing them as a mixture further assumes they can be managed similarly, including planting and harvesting the same day, similar irrigation, etc. A rotation that alternates different wheat varieties could also include other crops or fallow years.)

If there are dozens of suitable wheat varieties, though, you could have lots of diversity both at different spatial scales and over time: different two-variety mixtures in different fields, without having to grow the same variety in the same field in successive years.

My main worry, though, is that world food security relies so heavily on just three crops (corn, wheat, and rice). In both the book and the podcast, I argue that farmers making rational decisions about their individual risks and benefits will collectively choose less crop diversity than we need to ensure global food security. I doubt that this example made it into Robert Frank's book (see last post), but the issues are analogous to those that caused the recent Great Recession.

Emma Marris and I shared the stage at a recent event at Washington State University, organized by Andy McGuire. Emma argued that "hands off wilderness" and "preserving natural ecosystems in their 'pristine' state are incompatible. If keeping species from going extinct is more important than keeping them where they were in 1491 (or earlier, presumably, outside the Americas), then we should bet-hedge with a variety of approaches to conservation. Watch for her upcoming op-ed.


Both talks are part of symposia with other interesting speakers.

August 18: Student Organic Seed Symposium, NY Finger Lakes Region

October 28: minisymposium (with Emma Marris, author of "Rambunctious Garden: Saving Nature in a Post-Wild World") on "Saving Nature and Improving Agriculture: Where does Nature's Wisdom Lie?" Washington State University, Pullman

UPDATE: a Faculty of 1000 selection.

That's the title of a paper Toby Kiers and I just published in Philosophical Transactions of the Royal Society. We argue that:

"[despite] past selection for inclusive fitness (benefits to others, weighted by their relatedness)... [and despite some] evidence for kin recognition in plants and microbes... there is still ample opportunity for human-imposed selection to improve cooperation among crop plants and their symbionts"

Wednesday I'm off to the University of Illinois, where Michelle Wander and the Agroecology and Sustainable Agriculture program are using my book in a grad course on the Future of Agriculture.

Oct. 30, Horticulture Department, University of Minnesota
Nov. 21, Iowa State University
Dec. 5, University of California, Davis
Feb. 13, North Dakota State University
May 22. "Bioeconomy" meeting, Germany.

Talk titles are mostly something like:
"Darwinian agriculture: evolutionary tradeoffs as opportunities"

Photo at right is of Oberlin College, where I gave a department seminar last week and discussed my book with students in Angie Role's first-year seminar.

My upcoming talks

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I don't think my talk at Ringberg Castle next week is open to the public, but these departmental seminars probably are:

Sept. 27, Kellogg Biological Station, Michigan
Oct. 4, St. Thomas University, Minnesota
Oct. 11, Oberlin College, Ohio
Oct. 30, Horticulture Department, University of Minnesota
Nov. 21, Iowa State University

Talk titles are mostly something like:
"Darwinian agriculture: evolutionary tradeoffs as opportunities"

Talks in Mexico and Utah

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Last week I was at Mexico's National Laboratory of Genomics for Biodiversiity (Langebio), giving a keynote talk on Darwinian Agriculture and learning about the diverse research program there, from microbial communities to manipulation of ant "bodyguards" by Acacia plants to using yeast to answer fundamental evolutionary questions. I was invited by the grad students, which is always flattering. The chair of the committee, Sergio Campos, wrote that my book, "Agricultura Darwiniana":

"es una lectura imprescindible para aquellos interesados en la problemática de la alimentación mundial bajo un clima cambiante [que] nos ilustra acerca de cómo la biología evolutiva puede aplicarse en la tecnología agrícola y la biotecnología. "

Maybe there will be a Spanish edition someday, although I'd settle for an inexpensive paperback.

On Sunday, June 23, I'll be giving a talk on Darwinian Agriculture, as part of the "Evolution Out of Bounds" symposium at the Evolution 2013 meeting, in Snowbird, Utah. These annual evolution meetings are usually really interesting, as I've discussed previously, and other talks in the symposium range from evolution of disease to evolving robots. Those interested in our evolution-of-multicellularity research should look for the talk by Kristin Jacobsen on Sunday afternoon and the poster presentation by Jenn Pentz Monday evening.

Near the beginning of the question period for this recent lecture at the University of Minnesota, I suggested that:

1) nobody has done a good comparison of ideotype breeding with breeding for yield, and
2) many plant breeders who use the word "ideotype" ignore tradeoffs.

The main point of Donald's 1968 paper, which coined the term, "ideotype" was that there are often tradeoffs between individual-plant competitiveness and the collective performance of plant communities, so we can improve the latter by sacrificing the former. That's a major theme of my book, as well.

But both my numbered points above turn out to be wrong, at least partly.

Yuan et al. (2011) compared ideotype breeding with breeding for yield. I criticized some of their choices for "ideotype traits" in my third lecture at the International Rice Research Institute, but it's still an impressive study.

And, rereading Rasmusson's 1984 paper on ideotype breeding, I find extensive discussion of tradeoffs, though he doesn't explicitly mention the tradeoff between competitiveness and yield potential hypothesized by Donald (1968).

I am correcting these errors in an perspective I'm writing for the journal, Evolution.

...or whatever we call over 100 but fewer than 1000 views.

This page has links to an interview Michael Joyce did with me at the end of my week-long visit to the International Rice Research Institute, as well as the five lectures I gave there (plus audience questions and discussion).

Also still available are:
* a 60-second AAAS story on my most-cited paper.
* a video of my keynote talk at the Applied Evolution Summit
* a lower-quality video of a talk on Evolutionary Tradeoffs as Agricultural Opportunities
* an audio interview with science writer Carl Zimmer

Or, you can find an updated list of my publications, with links to many of them, here.

My talks at the International Rice Research Institute are have been posted on Youtube and have already "gone reptile" or whatever you call it when a few people watch them.

I've been enjoying my meetings with staff here. Some highlights so far:

Paul Hilario, curator of the IRRI museum, told me about the "community rat-barrier" strategy for reducing rat damage to rice. A small plot of rice is surrounded with a fence with a few holes. Rats are attracted to the plot and crawl in through the holes, each ending in a trap, so most of them are killed before they can reproduce. Sort of a black hole for rats. But it only works if the "trap plot" is more attractive to rats than other rice nearby. So coordination among farmers (planting nearby rice later than the trap plot) is key.

Next I met with Ruaraidh Sackville Hamilton, who's responsible for IRRI's 100,000-genotype rice collection. Here's a great story about that. He mentioned another example of cooperation among farmers being key to disease control. If every farmer in a region plants the same barley variety, that increases the risk of disease epidemics. So farmers in the UK coordinated choices to ensure high levels of diversity, at a regional scale. I don't know if this works better than if each farm had high levels of diversity, but it's probably better than if one farmer had high diversity and her neighbors didn't.

John Sheehy's seminar was another highlight of my first day at IRRI. He initiated a program to develop rice with the efficient C4 photosynthetic pathway, with funding from the Gates Foundation. That work is being continued by Paul Quick. They're using some very clever approaches, which I'll discuss in a later post, but success isn't certain and it will certainly take a while. So, Sheehy asked, what else can we do to increase the yield potential of rice?

Sheehy presented a bunch of simple equations: photosynthesis equals solar radiation times the fraction of that radiation intercepted by green leaves, times a radiation-use efficiency term, and so on. This overall approach is similar to what I used to teach in my Crop Ecology class at UC Davis, which I inherited from Robert Loomis. (Sheehy and I each taught the class as sabbatical replacements for Loomis, years ago, and we've both published on the physiology of legume root nodules.)

Sheehy pointed out that maximum yield occurs at the point when net growth is zero, that is, when biomass gets large enough that maintenance respiration balances photosynthesis. Maintenance respiration increases with temperature, so maximum yield will be less in warmer climates. This explains some yield differences that had previously been attributed to better cultivars or better management. I suspect that maximum production per day occurs much earlier than maximum yield, so it may make sense to harvest and plant another crop rather than waiting. Hoping to discuss this with Sheehy.

He also pointed out that leaves aren't important only for photosynthesis, but also as a place to store nitrogen which eventually gets used for grain nitrogen. You don't want the leaves so close together that they shade each other, so there are limits to how short rice plants should be, even though investing resources in stems rather than grain seems wasteful.