Andy McGuire, who earned an MS with me some years ago, doing research on cover crops, has just posted a provacative essay titled "Don't Mimic Nature on the Farm, Improve It." He contrasts a well-known agroecologist saying agriculture should "mimic nature" with statements from natural-ecosystem ecologists (and my book) denying the perfection of natural ecosystems and the "balance of nature" hypothesis. He concludes that:
"We can, with ingenuity, wisdom, and a good dose of humility, purposefully assemble systems that outperform natural ecosystems in providing both products and ecosystem services."
I agree, but with some reservations. If the overall organization of natural ecosystems isn't necessarily perfect -- see this discussion -- then it should be possible for us to improve on it, at least by agricultural criteria.
Let's consider a specific example: a pasture grazed by dairy cattle. We want to maximize milk production, subject to various constraints that include long-term sustainability and minimizing pollution. Our reference natural ecosystem is the prairie, grazed by bison, that once occupied the same land. The natural sex ratio of bison is 50:50, like other mammals, but we can get more milk from the same land with a female-biased sex ratio. Similarly, the ratio of nitrogen-fixing legumes to grasses in a natural prairie depends on their relative survival and reproduction, not on how much nitrogen the ecosystem needs for maximum productivitiy. Given the economic and environmental costs of nitrogen fertilizer, we might want to increase the abundance of legumes in our pasture, relative to the natural prairie.
But how? What combination of McGuire's "ingenuity, wisdom, and... humility" will lead to increased legume abundance with the fewest negative side effects? And are we even sure increasing legume abundance is a good idea?
Planting additional legume seed each year might cause enough soil disturbance to increase erosion. Low doses of a grass-specific herbicide would increase costs and perhaps pollution. Ingenuity might suggest introducing a mild pathogen that would slow grass growth without killing it. Humility, though, would identify some of the risks with that approach (for example, the pathogen might evolve greater virulence) and the possiblity of additional, unrecognized risks.
I would suggest trying several approaches in limited experiments (not including the pathogen option!), then doing longer-term and larger-scale tests of those that seem more promising. These tests may find problems that weren't apparent in short-term, small-scale experiments. (Similarly, we need more long-term monitoring of transgenic crops once they're in widespread commercial use. For example, an herbicide-resistant weed mutant is much more likely to arise on millions of acres than on one acre.)
But natural-ecosystem ecologists could play an important role also. For example, it might help us to know what combination of factors limits legume abundance in the natural prairie. If the preferences of grazing animals are key, can we enhance legume survival through grazing management? I don't mean to suggest that agronomists would never think of this without information from natural ecosystems, but comparisons among systems can often reveal patterns that aren't obvious in a single system.
Also, legumes and grasses have different soil-resource requirements. In particular, phosphorus fertilization can favor legumes more than grasses, although the long-term availability of phosphorus fertilizers is a concern. Differences in resource requirements among species have sometimes been proposed to explain the high species diversity of some natural ecosystems. On the other hand, a recent paper in Nature showed that differences in resource requirements among tropical tree species aren't enough to prevent loss of diversity during the seedling stage, when fungicide sprays reduce the diversity-enhancing effects of more-abundant species suffering more losses to pathogens.
This one is at the University of Illinois, "facilitated by Dr. Michelle Wander, and ASAP Scholars Rafter Ferguson and Ron Revord" and titled Agriculture Evolving: Evolutionary Dynamics from Crops to Ecosystems. I will be meeting with the class in April.
That's the topic of a thoughtful essay by Nathanael Johnson on the Grist website. He gives a reasonable summary of my argument that many hoped-for improvements either involve tradeoffs (some of them acceptable) or radical enough changes that their effects will be hard to predict.
He also cites my colleague Jonathan Foley's suggestion that "we" should "Reduce food waste, eat less meat, and make fertilizer and irrigation available to the farmers that need it."
OK, but who's "we"? Any "solution" that requires billions of people to change what they're doing -- because they read Foley's article in Science? -- will be a long time coming. For example, a few million rich consumers eating less meat -- this would lower the demand for meat so that meat prices decrease so that slightly-less-rich consumers eat more meat, but let's pretend total meat consumption goes down a few percent -- would not have much effect on global greenhouse gas production or food security for the billion or two in greatest need. Similarly, if a couple billion consumers wasted less food, that would free up some resources. But if you and a few friends reduce your waste, it's a drop in the ocean.
Reducing pre-consumer food waste has more potential. Because reducing pre-consumer waste could mean larger profits for farmers, food companies, etc., near-universal adoption of practical waste-reducing methods is at least conceivable. Motivation linked to higher profits also means, however, that the obvious improvements have already been made. Less-obvious improvements are already a major research focus, but more likely to be invented by engineers than ecologists.
Expanding access to irrigation might greatly increase food security, but it would be a big project, perhaps costing a significant fraction of what we spend on war or video games. So I'm not holding my breath.
Increasing access to fertilizer can start small and scale up -- avoiding over-fertilization -- so that's an area where contributions from a few million people (or a handful of rich people) could really make a difference. But I worry about solutions that require on-going subsidies.
And then there's plant breeding. Develop a cultivar that out-performs what's available now, and watch it spread.
There's an interesting discussion of this issue at Biology Fortified blog. The post is by my first MS student, Andy McGuire, who also has interesting things to say on a blog from Washington State University, where he works.
Andy's post was apparently inspired partly by something I wrote last year, showing my estimates of how much nitrogen flows from synthetic fertilizer to conventional corn to chicken manure to organic farms.
I don't get too excited about whether organic farmers should be allowed to use manure from conventional farms, or whether we should "blame" them for the fertilizer used to grow the corn to feed the chickens. My point was simply that this dependence limits the potential for expanding organic agriculture. (So advocates of organic farming should be showering me with money for research on nitrogen-fixing legume crops and forages -- but that's another story.)
More interesting is this open-access paper, titled "To what extent does organic farming rely
on nutrient inﬂows from conventional farming?" The paper has some actual numbers on nutrient fluxes to organic farms from conventional ones in France. While my earlier diagram assumed that an organic farm relied entirely on manure whose nitrogen originally came from synthetic fertilizer, the French study estimated that only 23% of nitrogen (though 73% of phosphorus) supply to organic farms came from conventional sources. But let's look at some details.
First, there are apparently some differences from US practices:
"European regulations recommend to use organically produced animal manure but allow the use of conventionally produced manure, provided that it is not the output of 'factory farming'."
I don't think we have that restriction in the US. Second, they found that:
"More than 80% of nutrient inﬂows through manures (82%, 85% and 81% for N, P and K, respectively)... came from conventional farming"
So 82% of N in manure came from conventional farms, but that was only 23% of estimated total N supply. The rest (almost 60% of total N inputs) was mostly estimated to come from biological nitrogen fixation:
"N ﬁxation was estimated using the model proposed by Høgh-Jensen et al (2004)... based on the total N amount in leguminous crop biomass, multiplied by the ratio between the amount of symbiotically ﬁxed N and the total N amount in the crop biomass."
That seems to be about all they said about biological nitrogen fixation -- I would have liked a little more detail. They also say that unsustainable "soil nutrient mining" (failure to replace nutrients exported in crops or otherwise lost from soil) was "not considered." A simple approach to that problem would have been to estimate nitrogen and phosphorus contents of products sold off-farm, and compared that to total inputs. If inputs exceed outputs, some of the difference may end up polluting groundwater, although some may be accumulating in soil, at least for a while. If outputs exceed inputs (including biological nitrogen fixation), over the long term, they will not be able to continue farming over the long term.
My conclusion is that organic farms that rely on manure from other farms (or on manure from their own animals, which are fed grain or hay from other farms) are dependent on conventional farms and therefore not a model that can be scaled up. That doesn't mean they are not making a positive contribution, if they are using manure that would otherwise end up polluting rivers.
If we can believe the nitrogen-fixation estimates in this paper, French farms are already getting a majority of their nitrogen from symbiotic rhizobia in the root nodules of their legume crops and forages. Maybe that could be scaled up. But if 75% of their phosphorus is coming from manure from conventional farms anyway, there may be little point in trying to replace the nitrogen in that manure with biological nitrogen fixation.
I"ve finally found a version of Linux that meets most of my needs, out of the box, without a lot of fuss. Meeting "all my needs" requires the occasional use of Windows programs, either by dual-booting to Windows or running Windows in a virtual machine. Neither was very difficult; see below.
I've been using WIndows and Microsoft Office for many years, but have been finding them increasingly annoying, with "updates" that were worse than the versions they replaced -- forced on us by their use of new file formats (docx, etc.), GHz computers running slower than MHz computers used to because of all the bloatware, etc. Sticking points in earlier versions of Linux I've tried were:
* Support for two monitors on my desktop PC, one requiring rotation for portrait mode.
* Support for WiFi on my Acer Aspire One netbook.
* Support for a few Windows-only applications, notably MathCAD and Livescribe pens, which record handwritten notes in a proprietary format, which can be exported to PDF bitmap images and text or spreadsheet files, as I've discussed before.
Linux Mint handled both of these with ease.
Linux Mint comes with LibreOffice, which handles some things (e.g., importing from various spreadsheet file formats) better than Microsoft Office. It even imports and exports docx, which I suppose will just enable people to keep using that evil format. I'm not sure .odt is better, though. If I can't edit a document file with a plain-vanilla text editor, it's harder to process it with Python.
I also used Linux Mint's package manager to install VirtualBox, installed Windows XP within VirtualBox, and installed MathCAD (one of the few Windows programs I can't do without) on the XP virtual machine. I couldn't get the VirtualBox version of XP to use my second monitor, but if I need two monitors for a Windows program I can still boot to my old copy of XP. Within Linux Mint itself, setting up the two monitors and rotating one was easier than it had been in XP.
I used the same DVD (and an external drive) to replace the aging operating system on my Acer Aspire One with Linux Mint, encouraged by this video. Mint seems to connect to Wifi faster than Linpus did, though other operations seem slower. Mint found my video camera but not the microphone, so I may have to use an external headset for Skype or Google Hangout -- but I couldn't get either of those to work at all with the previous operating system. Mint doesn't respond to tapping the touchpad either, but the buttons work. The netbook seems to lock up more often than it did with the less-capable older version of Linux, so I may be pushing the limits of what you can do with 500 Mb of RAM.
Maybe these minor problems can be solved, but I'm really impressed by how well Mint worked out of the box on both desktop and netbook.
Getting Livescribe Desktop working was a bit of a challenge:
* Installed VMware (may be possible with VirtualBox, but maybe harder)
* Installed WindowsXP as virtual machine, from original CD.
* Installed .NET framework 2 (otherwise Livescribe Desktop installs, but won't run)
* Downloaded and installed Livescribe Desktop.
Once I did all that, it was able to upload and display pages from my Livescribe Echo smartpen, a very useful tool for lab notes, as I've discussed elsewhere.
Amazon's "Author Central" gives sales by region, within the US. I'm not surprised that Minnesota is #1, since people here know me and since I've given seminars on the book for two University of Minnesota departments and the University of Saint Thomas. But the Sacramento region, home of UC Davis (where I used to teach and where Robert Hijmans used the book in a seminar for graduate students in ecology) was edged out by Boston, which isn't known for its agricultural colleges. Are a bunch of smart and curious Bostonians independently broadening their education, or is there a class using the book there that I don't know about? Or a book club? It would be great for the more-intellectual sort of book club...
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.
Field Crops Research, a leading agricultural journal, has just published a review of Darwinian Agriculture by Jeffrey White. He suggests that there is "ample scope for debate and further research on speciﬁc propositions of Darwinian Agriculture." I agree and look forward to those debates. For example, I argued that perennial grain crops may never approach the yields of annual grains, because perenniality requires investing resources in over-wintering that could otherwise by used for grain. White agrees that this may be true in temperate climates, but maybe not in the tropics, if the "off-season" is short. He gives "perennially cropped sugarcane fields" as an example.
I agree that perennials can potentially capture a larger fraction of annual solar radiation, as I noted in the book. For example, a time-lapse movie of rice growth shows that this "annual crop" (which may be grown 2 or 3 times in a year) completely covers the ground only a small fraction of the time. Most of the time, sunlight is mainly hitting soil, evaporating water rather than powering photosynthesis. Perennials can use some of last-season's photosynthate to power rapid leaf growth, capturing a larger fraction of solar radiation sooner.
This isn't only true in the tropics. For example, the book cites a study showing that perennial Miscanthus can produce more biomass than corn. The photo below shows the Miscanthus plots Steve Hamilton showed me at Michigan State's Kellogg Biological Station, where I gave a talk earlier this month. But this Miscanthus doesn't produce any seed and I don't think sugarcane produces much.
What about perennial grasses that do produce significant amounts of grain? Sieglinde Snapp and colleagues at Kellogg Biological Station and The Land Institute have shown that perennial intermediate wheatgrass (kernza) can reduce nitrate concentrations in soil water much more than annual wheat, presumably reducing pollution of wells and rivers. But its first-year grain yield was only 112-157 kg/ha, versus 2807-3761 kg/ha for annual wheat. (Interestingly, the higher yields were with organic management.) Second year yields were 1390-1662 kg/ha for the perennial versus 4248-5017 for the annual. Unless the perennial really improves in subsequent years, the perennial would take more than three times as much land to produce the same amount of grain. I worry that the additional land will come from clearing forests or draining wetlands.