Can organic farming feed the world?

I discuss various aspects of so-called ‘alternative’ agriculture at some length in Chapter 6 of A Small Farm Future1, and I don’t intend to retrace many of those steps here. But there’s a couple of further things I do want to say in this blog cycle. Here, I’ll focus on organic farming.

On page 125 (and also page 150) of my book I cite a 2007 study by Catherine Badgley and co-authors2, one of whom is Jahi Chappell who sometimes comments here, so I’m hoping he might weigh in with his thoughts on this post. Their paper suggests that organic agriculture based on biological fixation of nitrogen is capable of meeting global food demands without reliance on industrial synthesis of nitrogenous fertiliser (from now on in this post I’m going to use the symbols N to refer to plant-available nitrogen, BNF to refer to biological (or ‘organic’) nitrogen fixation and SNF to refer to synthetic/industrial nitrogen fixation). Interestingly, the Badgley paper also suggest that while organic yields in rich countries are typically lower than their ‘conventional’ counterparts, the opposite is often the case in poor countries, a point to which I’ll return.

Since the publication of my book, I’ve become aware of various papers by Professor David Connor critiquing the Badgley paper, and more generally the notion that it’s feasible to feed the world without SNF. Although I identify with organic/alternative agriculture and have never used synthetic N in my own farming, I don’t take an absolutely purist line about it in relation to the global food system. If SNF is necessary in some circumstances, I’m not going to lose sleep over it. Still, SNF is an energy-intensive business requiring a complex industrial infrastructure. Given energy and other constraints in the future, if it turned out we needed SNF at similar levels to the present to feed the world this would be quite a stumbling block for arguments favouring low-energy agrarian localism. So it’s worth considering Connor’s arguments.

The main objection to the possibility of ‘feeding the world’ through organic agriculture based on BNF is that it’s typically lower yielding than SNF-based agriculture. This yield penalty has two components – lower yield acre for acre in the corresponding crops, and the fact that organic agriculture has to build N via rotations with leguminous non-food cover crops that further increase its land-take. Connor argues that the Badgley paper failed to take proper account of this second issue, and therefore overestimated the global potential of organic agriculture.

Whatever the rights or wrongs of that point, I’m going to take a different tack and consider some figures that Connor presents3. He says that 21 Mega tonnes (Mt) of N are fixed annually by cover crop legumes, with the total amount of BNF estimated between 33-46Mt. This contrasts with 113Mt of SNF, giving the measure of the challenge – apparently a major shortfall in the possibility of feeding the world organically.

But let’s take a closer look at these figures, most of which are based on a 2008 paper by David Herridge and co-authors4. I’m going to see if I can find some ways to narrow the discrepancy between BNF and SNF reported by Connor, which at worst is over a fivefold difference in favour of synthetic (113:21). It’s rather a back-of-the-envelope job, and some of the underlying issues are quite complex, so of course I’d welcome any comments or refinements.

The Herridge paper that Connor draws on proposes a larger amount of global BNF than Connor of 50-70Mt, as follows:

Pasture & fodder – 12-25Mt

Rice – 5 Mt

Sugar cane – 0.5Mt

Legume cropland – 21.45Mt

Non-legume cropland – <4Mt

Extensive savanna – <14Mt

 

Connor’s 33-46Mt figure presumably comes from adding legume cropland to the lower and higher bounds of the pasture & fodder figures (21+12=33, 21+25=46), so he’s ignoring the other forms of BNF reported by Herridge. This seems reasonable in the case of extensive savanna, little of which is likely to find its way back into the agro-ecosystem, but not so reasonable in the case of the other, admittedly fairly minor, BNF sources – rice, sugar cane and non-legume cropland. So I propose to incorporate these into the BNF figure. This gives a range of 39-56 Mt BNF, something of an improvement on the worst-case ratio, but still at best only half the SNF figure.

Let’s now look at livestock. According to the FAO, 33% of global cropland is devoted to producing livestock fodder. This is a choice that humans make – in fact, that primarily rich humans make – and I’d suggest not a wise one in view of the energy and other squeezes we face. Therefore, I think we can drop it from our modelling. We need to design a renewable food system that can feed the global population adequately, fitting livestock into it where we can, rather than designing livestock systems to meet the demand for meat which compromise food access and renewability.

I’m not sure quite how to quantify this adjustment, however. Soy is a major fodder crop, and also an N-fixer, so possibly the proportion of global cropland devoted to producing fodder has lower SNF needs? Obviously, some of the N that’s fixed ends up in the fodder and not in the field, although some of that then ends up in manure which may be available as BNF. But I’m not sure how best to adjust for these pathways – and of course there are a lot of non-N fixing fodder crops. So for now I’m going to allocate 33% of SNF proportionately to the 33% of fodder cropland, until someone suggests a better methodology. So that’s 33% of superfluous SNF, which takes us down to 76 Mt SN.

SNF used for boosting the productivity of long-term pastures for livestock is, I’d argue, another superfluous use. I don’t have global figures for this. Rough calculations for the UK suggest that we use about 30% of our SN on pastures. I suspect the figure is much lower in most other countries. I’ll arbitrarily assume that it amounts to 3% globally – further information welcome. This would take total SNF down to 73 Mt.

The next thing to look at is human waste. Each of us excretes about 20g of N per day in urine and faeces – which amounts to a lot of N aggregated across the human population over a year. Here in the UK, we already do a pretty good job of getting this back to the fields, but at quite a high energetic cost in water treatment and transport. One of the arguments in favour of ruralization is that it’s much easier energetically to get human nutrients back into the fields when people are actually living on them (a graver threat to urbanism than many seem to appreciate, especially in relation to phosphate rather than N). Let’s assume we can get 75% of the N contained in global humanure into the fields (again, I’m open to a more refined analysis with this parameter). This shrinks annual global SN to 25 Mt.

Then there are various losses associated with international trade, processing and consumer waste, which could be vitiated in a society based on local food production. I estimate these at a rough and ready 19% on the basis of a paper by Mike Berners-Lee and colleagues5 – admittedly one with a somewhat different focus, so again I’m open to more nuanced clarification. This reduces SN to 20 Mt – about the same as BNF from legume cropland, and much less than is currently fixed by BNF overall.

There are various other ways in which we might nibble away at this remaining SNF figure. For example, we might invest more in plant breeding and crop development to maximize edible matter per unit of N input and increase organic yields, which has scarcely been an agronomic priority in recent times. Or we might increase the N input from wild margins either directly or through livestock intermediaries, or cut back on certain kinds of N-demanding production, or improve crop production through other means like irrigation, or improve N uptake in existing crops. Maybe we could reduce SN by such means to around 10 Mt, down from the initial figure of 113 Mt. The possible fivefold excess of SN over BFN (113:21) may now be reversed (10:56) – perhaps to the extent that it’s no longer wholly implausible to imagine a low-energy small farm future that’s largely an organic one?

A final point. Professor Connor writes:

“My concern is for the resource-poor farmers, especially in Sub Saharan Africa, who overwhelmingly are targets for help and advice to apply organic methods from misguided community organizations based in other countries. Soil fertility is so low there after at least a century of intensive nutrient extraction without replacement that denial of the need for N fertilizer makes the process of agricultural renovation impossible”5

 

This concern seems a worthy one. If the world does still need a modicum of SNF, the people who unquestionably need it most are poor (usually small-scale) farmers in regions like Sub-Saharan Africa. Whether those advising these farmers to apply organic methods are ‘misguided’ is another matter, because there’s a long history of poor farmers getting locked into dependency on high-cost inputs like synthetic N, largely to the benefit of those selling the inputs rather than to the farmers. So the advice of movements like Zero Budget Natural Farming in India for poor farmers to farm organically without SNF seems to me well founded. The higher yields for organic farming in poor countries reported in the Badgley paper seemed to arise from the availability of extension and advice helping farmers to manage inputs more systematically. This should surely be the first option to explore in improving yields before moving on to more energy-intensive options like SNF.

But perhaps we can frame this point about nitrogen equity the other way around. Given the grossly unfair distribution of global resources, rich countries should stop trying to squeeze greater productivity out of their own farming systems through profligate (or, perhaps, any) use of SNF, and make SN available at low or no cost to poor farmers in poor countries, should the latter feel the need for it.

 

Notes

  1. Chris Smaje. 2020. A Small Farm Future. Chelsea Green.
  2. Catherine Badgley et al. 2007. Organic agriculture and the global food supply. Renewable Agriculture and Food Systems 22: 86-108.
  3. David Connor. 2018. Land required for legumes restricts the contribution of organic agriculture to global food security. Outlook on Agriculture. 47: 277-82.
  4. David Herridge et al. 2008. Global inputs of biological nitrogen fixation in agricultural systems. Plant and Soil. 311: 1–18.
  5. Mike Berners-Lee et al. Current global food production is sufficient to meet
    human nutritional needs in 2050 provided there is
    radical societal adaptation. Elementa: Science of the Anthropocene. 6: 52.
  6. David Connor. 2018. Organic agriculture and food security: A decade of unreason finally implodes. Field Crops Research. 225: 128-9.

31 thoughts on “Can organic farming feed the world?

  1. I think I would work things out from the other direction:

    How much land is required to grow food for one person, assuming they only use cover crops for nitrogen fixation? Does this change with the addition of livestock? (That is: can livestock concentrate some nitrogen for us, without eventuallly depleting the ground used to grow their feed? I guess that depends whether they’re eating clover…) What about the addition of nitrogen-fixing perennials? At what point of lack do other flows (water, phosphorus, etc) become the limiting factor on growth? Obviously land in sub-saharan Africa that has been intensively farmed for at least a century without nutrient replacement is going to have a different answer than, say, my allotment — though it’s interesting to look at how different plots on the site are managed and the resulting changes in ground level and soil structure (the default is heavy clay, but some plots are about a foot below the level of the pathways, and others have beds a good eight inches higher — these latter always have a rich loam). Conversely, there does seem to be a point where adding more nitrogen, in whatever form, doesn’t help anything at all, because even if you optimise water, soil structure, nutrients, and so on, there is after all only so much sunlight. But really we’re looking at “five acres and a cow” territory. For most of history the limiting factor has been human labour, of course.

    I think another important point of comparison might be how much nitrogen is wasted in each method. While nitrogen excess can surely cause problems for growing food, my understanding is that synthetic fertilisers, due to their water solubility, can be a great way to fix nitrogen and use it to pollute groundwater without much benefit to crops, so just because a certain amount of synthetic nitrogen fixation is in use doesn’t mean that much is necessary. I know manure can also be “lossy” like this, hence composting it rather than applying it neat.

    Additionally, industrial monoculture crops grown with synthetic fertilisers for the purpose of sale on global markets are not generally bred or grown to optimise micronutrient content, and if food is less nutritious we may need to eat more of it, or at least suffer a marked increase in apetite. (There are people looking at micronutrient density and apetite using smartphone app food tracking logs — but they are looking at it in weight loss terms, of course.) Meanwhile cover crops and manure (human or animal) can improve soil structure and add or redistribute other nutrients, not just NPK.

    “How much manure do you need to use to replace the SNF currently in use?” seems like a misleading question, in that respect.

    All that said — I agree with you that poor people attempting to farm in heavily depleted soils should have “first dibs” on the use of synthetic nitrogen products, while also noting that the use of locally appropriate biological materials (cover crops, manure including humanure, etc), while labour-intensive, will likely lead to more long-term autonomy from global markets, as well as providing other benefits beyond those of synthetic fertilisers.

  2. Chris wrote, “Then there are various losses associated with international trade, processing and consumer waste, which could be vitiated in a society based on local food production.”

    The referenced paper by Mike Berners-Lee has a reference to another paper which actually quantifies the fertiliser used to produce the Food Supply Chain losses:

    “total fertiliser use for FSC losses (28 Mt of nutrients per year) is larger than the current fertiliser application in Africa and Europe together” (page 487)

    “23–24% of total use of water, cropland and fertilisers are used to produce losses.” (page 477 Highlights)

    Lost food, wasted resources: Global food supply chain losses and their impacts on freshwater, cropland, and fertiliser use
    M.Kummu et al.
    https://www.sciencedirect.com/science/article/pii/S0048969712011862

    • In his book “Meat, A Benign Extravagance,” Simon Fairlie references the book “Enriching the Earth” by Vaclav Smil, saying that 45% of food in the USA is wasted, and this has major implications for fertilizer usage:

      “Smil calculates that the USA, even though it is the world’s second largest consumer of nitrogen fertilizers after China, ‘in the 1990s could have supplied a healthy diet for 250 million people without using any synthetic nitrogen compounds.’ This could be achieved by reducing food exports, the amount of grain-fed meat, and most significantly the 45 percent of food which is wasted. No doubt countries such as Canada and New Zealand could feed themselves just as easily, and I suspect that France, and even Britain could feed themselves through organic home production, though we British might have to eat more porridge and potatoes.” (page 89)

  3. Chris said:

    “… we might invest more in plant breeding and crop development to maximize edible matter per unit of N input …

    and he also asked…

    Soy is a major fodder crop, and also an N-fixer, so possibly the proportion of global cropland devoted to producing fodder has lower SNF needs?

    To the first I’m most certainly in agreement. To the second – what??

    I won’t go banging on about the values of plant breeding… it is real, and amortized over a long future the costs are reasonable – making the art and science of it about as smart an investment as human kind has attempted. [but I’m biased on the matter]. So yes, let us continue to breed plants and develop crops for our own survival. And keep soy in the mix.

    Soy is a remarkable species to breed. Most might consider soy a grain crop rather than a fodder crop (unless one lumps all animal feeds into a ‘fodder’ designation). But either way, soy, due the vast amount of land upon which it is currently planted is easily the most significant legume and N fixer to hand. Soy can indeed be planted as a fodder crop, and in very high latitudes – above 55 degrees N (or below 55 degrees S) where soy grain production is currently challenged by day length matters it can still be grown for its vegetation (and if the soil has Bradyrhizobium it can fix N.

    But a point I don’t mean to pass over is that soy is and will continue to be a significant source of high quality calories for humans. In the U.S. estimates of the proportion of the soy crop headed directly for a human gut is less than 20%. Sure, a VERY sizable portion ends up feeding humans after passing through an animal for eggs, milk, and meat… and some animal wastes can be recycled. But if a smaller animal use is employed, then we find ourselves with far more soy than we need.

    Above I extolled soy as perhaps the most significant N fixer in our tool box. And on land I’ll stand by that. But what about in the planet’s watercourses?? N fixing in the open ocean and in fresh water systems really occurs. And fishing takes advantage… but there are other ways to improve our food needs from water systems. But we should be very careful going into the open ocean with designs to “farm” like we have on land… our land based track record being what it is.

    • On a small enough farm I’m not sure day length is so much an issue — covering a greenhouse or open frame, say, with an opaque cloth or shutters in the evening and opening it again in the morning would be labour intensive, but not ridiculously so. (I think in places where day length is a substantial issue for growing beans, some kind of frost protection is likely to be a good idea at each end of the season, too…shutters would do this also.)

      I hadn’t even thought of water-based nitrogen fixing. Staying the heck out of the ocean seems wise, but should small farms consider spirulina aquaculture or similar?

    • Soy is beginning to be seen as a problem there is research staying is is involved with Alzheimer and autism being a foodstuff it has never really been investigated in medical problems .

      • That’s an interesting claim. Soy has been a direct human food for more than 3 millennia … with some evidence suggesting human consumption for 5 millennia. In fact the evidence for animal feeding safety is less established – though even there the track record is long and well documented.

        Feeding carnivorous fish with soy is getting a serious look now – the history of this use being less than a human generation in length. This latter application is all about the Benjamins – aquaculture for salmonids relies on fishmeal, and fishmeal is more expensive than soybean meal. And as soy uses BNF instead of SNF it fits our longer term objectives quite well.

        Soy has rapidly grown into a very significant plant resource. Other plant species like the cereal grains have lost market share as a consequence. In cultures where soy does not enjoy the cultural history it does in the East there will be detractors. Properly cooked and prepared soy offers tremendous potential for human diets. Consuming soy exclusively would be a bad idea. Fit it into a balanced and diverse diet and you have a winning approach.

        • I lived in both the UK and the USA there is a vast difference between the pork here and the UK , soy meal used here ( USA ) makes the meat bland and slimy ,with little taste U.K. Pork is a far superior product , my pigs eat no soy products ( pasture raised ) and there is a wating list for the meat .

  4. For the most part, organic agriculture in the rich world is being practiced as industrial agriculture. As such, regardless of the source of N, it is still subject to most of the same problems as conventional agriculture, mechanization, long supply chains both in and out of the field, heavily processed products, storage costs and massive amounts of packaging to enable entry into grocery stores, restaurants and institutional settings.

    The main advantage of organic agriculture should be the maintenance of soil microbiomes and general soil fertility. But a commercial farm can be organically certified and still import most of its nutrients. My neighbor’s sons have an organic farm growing vegetables. At first glance one wouldn’t be able to tell any difference between their farm and a non-organic farm. Only a close look at the label of the bagged fertilizer used to grow their crops would reveal that it didn’t contain synthetic fertilizer. Much organic fertilizer is made from ‘waste’ materials, but preparing it for entry into the industrial supply chain is a complicated and carbon intensive industrial process. And then there’s the whole world of organic pesticides.

    https://www.fertilizer-machine.net/solution_and_market/organic-fertilizer-production-process.html

    Over ten billion net tons of carbon are emitted into the atmosphere by human action every year. One hundred twenty million tons of CH4 turned into 80 million tons of NH3 would constitute only a little over 1% of total carbon emissions. Loss of soil carbon from poor agricultural practices, whether organic or conventional, dwarf the carbon emissions from synthetic fertilizer production. And of the estimated 133 billion tons of soil carbon lost since the dawn of agriculture, only a small fraction has be lost since the invention of synthetic fertilizer. The rest was lost in a world of 100% organic agriculture.

    So, in my view, sustainable food production will certainly be organic, but organic food production is not necessarily sustainable. Sustainable food production comes from non-industrial organic farms. If I had to, I would choose non-industrial farming with synthetic fertilizer over industrial farming with organic fertilizer. It’s closer to where we need to go, a small farm future.

    • Replacing some soil carbon is something that manure and some cover crops do that synthetic fertilisers don’t, of course.

      After a year on the allotment I do find myself thinking of sweetcorn and sunflowers as useful to grow partly because they produce massive thick stems that can be chopped up and fed to the compost bin. My understanding is that the carbon mostly comes from the air.

      • But synthetic fertilizers increases biomass production therefore, if some of that biomass stay on site it could increase SOM. Roots, cover crops, crop residues etc, Its not the source of the nutriment but how we use it. I think we should stop opposing SNF and BNF, if used properly, they can be both very useful tools for better farming practices.

        • Colin makes an excellent point here – IMHO. The nitrogen itself isn’t to blame. Overuse by humans is a problem. Unaccounted externalities in the production pathway is a problem. [for which I would tweak Colin’s “its not the source” IF the various sources are compared for ALL their real costs].

    • I remember when living in the UK our first use of nitrogen , it was used in old pasture white clover lays used for hay , we had a converted drag horse type knife / sickle mower , it would not look at the crop , we had to buy a power driven mower to cut it , the difference three and a half tonnes to the acre with added nitrogen .

  5. Thanks for all these very interesting comments. Rather than attempting to reply to them here, I’ll aim to write a follow up post which picks up on them.

    So for now just a couple of points of clarification. I probably confused things by using ‘organic farming’ in my title, which risks conflating commercial farming that’s formally certified as organic with the wider question of organic sources of fertility in producting human food. I agree with Joe’s remarks about the former, but that still leaves open the question of how best to approach the latter … so I’ll come back to that.

    Second, to Clem’s question about my question “Soy is a major fodder crop, and also an N-fixer, so possibly the proportion of global cropland devoted to producing fodder has lower SNF needs?” –

    So…yes, I’m just using ‘fodder’ generically to mean stock feed. The point I’m trying to make is that in my opinion we can do without the 33% of global cropland used to grow stock feed, so I adjusted the SFN figure downwards by 33%. But I was wondering if there’s relatively more soy (or N fixing plants generally) in this 33% than there is in the 67% devoted to human food, because if so I possibly shouldn’t adjust the required SFN down so much. The food system N pathways here are a little complex, but if anyone has any further thoughts on this point I’d be interested to hear them.

    To the various other points, I’ll say more in next post. Thanks!

    • Wonder how much of that 30% of cropland growing soy will just change from feeding animals to growing feedstock for fake meat factories ?

      • That’s an excellent question… and the answer lies with consumers. If enough people want to consume the faux meat that will rely pretty heavily on soy and peas as feedstock, then a proportion of the 30% will still be grown. The biggest difference between feeding a critter first and making faux meat directly from plant protein is the gain in efficiency (manufactured is more efficient – at least in most analyses I’ve seen… externalities not always accounted for).

        If consumers balk at factory meat, then animals will continue to serve (unless or until our stress on the habitat grows so severe our hands are forced otherwise). My opinion – both will co-exist for some time. The PETA folks and other vegan oriented communities will go for plant protein products, and communities around grasslands will likely continue to graze on herbivores.

  6. I understand the desire to engage with the argument that organic farming can’t feed the world. Instead of ceding the framing of the question, I prefer to ask, “How will industrial ag feed the world in 50, 100, 200 years? It will take many years to make a transition, so there is no time to lose. Unless that question can be credibly answered, the direction forward is obvious.

    I know there is a good bit of denial in our society, but serious folk are slowly beginning to wrestle with the fact that resource peaking is imminent, if not already here.

    Organic farming ( defined as low input, mimicking natural nutrient and energy flows) will be the only choice at some point, and we’d best begin now refining our methods, shifting cultural habits ( less meat, more perennials) and figuring the transition path.

    • Industrial farming can’t feed the world even today, as millions are starving. By and large I believe the question is wrong as it implies that it is the production method that determine if people will get enough to eat, but it isn’t, it is rather how we organize society,

      • Gunnar – I’ll agree and disagree…

        That millions presently have either too little to eat (and thus are starving) or have too poor or incomplete a diet is indeed evidence the collective “we” are not feeding the world – whether industrially or organically.

        Thus, the simple title of this post is off a touch… but if the consideration is whether organic production can provide a similar level of calories to those provided industrially – then we come to what I consider the issue at hand.

        By the same token, suggesting that how we organize society is going to solve the starvation issue is fraught with incompleteness. The most benevolent society imaginable won’t feed us all if we don’t have the calories (total and of sufficient quality) to serve.

        Tying the two together – organizing society to both produce AND equitably distribute the needed nutrition is the chore before us. And not for nothing – the equitable distribution side of that might well consider reducing wasted food. We can make much of the metaphor of a food web… beyond the typical usage where we account for the complex web of potential ingredients. The web could also ensnarl concepts of distribution, waste amelioration, habitat protection, and so forth.

      • Even “organizing society” won’t solve the problem for the long term.

        We are destined for a small farm future once our energy resources run down and when that future comes it will be energetically sustainable, but it will also suffer more from local disruptions to farming. Without global supply chains to buffer climatic and disease impacts on yield, famine will tend to occur almost continuously somewhere in the world (just as it always has in human history). And this is after the major famines that will occur as 8 billion people go through the bottleneck.

        Our best chance to make sure everyone is fed an ample and healthy diet is right now, when energy is available to move lots of food lots of miles. Of course, we are not taking advantage of this temporary benefit due to our reliance on markets for distribution. But soon, even the possiblility of an ample and universal food supply for everyone will disappear. We will be back to praying for rain clouds to arrive and for clouds of locusts to stay away.

  7. Thanks for the post, Chris. I’ve recently enjoyed reading your book and am running through it a second time, taking notes and adding many lines to my own personal bibliography (dangerous to do as the gardening season is beginning).

    Many interesting questions here. Being someone who has worked on a variety of organic farms (certified and not, industrial-scale and not), I do know that there is a heavy reliance on “conventional” manures in both small and large-scale organic fertility programs (I’m coming from a U.S. perspective, but as far as I understand, the EU permits the use of conventional manures in organic cropping systems). Particularly favored is conventional poultry litter as it is easily dried, pelletized, transported, and dispersed. This fertility is of course sponsored by Haber-Bosch N fixation.

    I came across an interesting paper by Nowak, et al (2013), attempting to quantify the off-farm nutrient inputs on 63 organic farms in France. Their results showed that ~23% of N inflows came from conventional agricultural sources (mostly in the form of manure, some fodders). Some proportion of that inflowing N certainly has its source in leguminous N-fixation (BNF), but a significant portion also must come from SNF. The authors highlight that the farming system, farm diversity, and regional agricultural context were highly determinant in what the ratio of inflowing N involved.

    Interestingly, 73% of P, and 53% of K inflows came from conventional sources, as well. This suggests a high level of reliance on mined and synthetically fixed nutrients cycled (or more cynically, “laundered”) through conventional systems.

    This doesn’t directly address your calculations about whether it is theoretically possible for BNF to account for current SNF use, but does throw some light on the current practical and cultural realities of organic farming/gardening and the food supply.

    For organic farms to “feed the world,” it seems that a lot of progress will have to made not only in terms of crop breeding, but also in terms of on-farm or regional agricultural diversity, as well as more skillful management of on-farm N cycling to improve N efficiency and avoid unnecessary losses (see Gaskell and Smith 2007: https://biosci.com/wp-content/uploads/2019/02/nitrogen-sources-for-organic-vegetable-crops.pdf).

    Thanks for the interesting discussion.

  8. There are several ways to increase yields in agriculture, of which the use of chemical fertilizers and pesticides are just two. They are admittedly important, but one can increase productivity by deploying more work, other nature resources (e.g. water), by switching crops or taking more crops per year. What is done is mainly determined by economic factors. Very few farms, organic or non-organic, produce at their maximum, but they produce what is optimal given prices of factors of production and output prices. In most cases, production per person has been much more important that production per unit of land. But in a world with limited land resources and 9 billion people, this will sooner or later change.
    In addition to your references I would recommend also: Muller et al, https://www.nature.com/articles/s41467-017-01410-w
    my own reflection on their research: https://gardenearth.blogspot.com/2018/01/yes-we-can-feed-9-billion-with-organic.html
    There is also an FAO scenario showing that it is possible, yes even desirable to fees the world without synthetic fertilizers, https://gardenearth.blogspot.com/2019/03/only-possible-to-feed-people.html

  9. Pingback: Can organic farming feed the world? – Olduvai.ca

    • While I was at the Dartington registration page I noticed that the Chelsea Green logo features a gigantic Orthoptera about to devour a stalk of grain, something that would make any farmer shudder. Chelsea Green probably thinks it looks cute. You may have the clout to get them to change their terrifying logo.

    • FYI, I just tried to book a ticket to your Dartington webinar and was not allowed to book online. Sorry I missed it.

      • I heard back from Dartington: “We close booking for all our online events between 1 hour and 12 hours before the listed start time. This is to give us time to ensure that everyone has received the joining instructions ahead of the event”.

        I was too late. I hope others here were not.

    • Sorry about your difficulties booking in, Joe. I think the session will be on Youtube fairly soon – I’ll mention it here when it’s up.

      …and I’ll pass on your comments to Chelsea Green about their logo 🙂

  10. Pingback: Some further thoughts on organic fertility - Resilience

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