The Carbon Farming Solution read-along discussion - Part 2: A Global Toolkit of Practices & Species

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The CARBON FARMING SOLUTION - A Global Toolkit of Perennial Crops and Regenerative Agriculture Practices for Climate Change Mitigation and Food Security

by Eric Toesmeier

Part 2: A Global Toolkit of Practices & Species

6. Annual Cropping Systems
7. Livestock Systems
8. Perennial Cropping Systems
9. Additional Tools
10. Introduction to Species


For this discussion, the emphasis is to be on how we can use the information from the book to mitigate climate change and rising levels of CO2. We're looking for solutions, not debate about whether or not there is a problem. I'd like the discussion to be positive, helping people to make appropriate decisions, encouraging any step in the right direction. Off topic posts and anything that smells like trolling will be removed.

I admit, I'm behind on my reading. I'm really enjoying chapter 6, the one about Annual Cropping Systems and how we can improve them. I'm trying to finish a chapter a day, which isn't too bad as the font in this book is fairly easy for a language challenged person like myself.

However, chapter 7, I'm a bit worried about how the discussion about that will go. I'm worried there will be an attempt to discuss the way our diet influences global warming and that's not what the chapter is about. People eat meat, yes, I feel it would be nice if they ate less, but that's the breaks, they eat meat and it has an ecological impact - this has been discussed ad nauseum elsewhere. We don't need to go into it again here. Assuming that people are going to raise and eat meat, no matter our own personal views, let's we are going to focus on how this system can be improved in the context of carbon farming. If you wish to debate or focus on the problem, please take it to the cider press.

This thread is about solutions.

Perhaps not surprisingly, I disagree. The whole book is about the fact that we are going to have to change not only the way we produce food, but what we eat. I also intend to address other issues mentioned in this section which have been discussed already. I'm more than happy to accept that some, even much, of what I eat will have to go, even many personal favourites, because annual cropping presents carbon sequestration and emission issues.

I'm going to have to cut down on potatoes! There is no discussion on how we can make potato farming better. They're part of the problem. I treat chapter 6 (Annual Cropping Systems) as an interim model while we get the perennial systems up and running (although I do want to address some food security issues, but may wait until part 5 or cover it in the review I'm slowly working on).

Why are we then expected to give ranching which, as the book makes clear, can only provide marginal carbon sequestration in ideal conditions, typically using resources such as compost and straw (what Toensmeier dismisses as "agricultural waste) better used elsewhere in order to do so, a free pass? I don't want to sit here and say that "people will always eat potatoes": they're a recent introduction to this continent, just as meat was a rare treat until it became a status symbol of the affluence that got us into this problem.

It seems to me that discussion of diet would be central to a discussion of farming.

Since potatoes are so productive I expect them to be around some time ,other crops not so much .
Feed a family of 8 on 2acres whilst you need 12 acres to feed the same family on Wheat .

David

David Livingston wrote:Since potatoes are so productive I expect them to be around some time ,other crops not so much .
Feed a family of 8 on 2acres whilst you need 12 acres to feed the same family on Wheat .

David

And there are still families of 8 in the developing world. I tend to forget that.

The problem with potatoes (and indeed wheat) is the low or negative rates of carbon sequestration. If we're going to make this work we're going to need massive areas of farmland with high levels of carbon sequestration. That means that most annual cropping systems may need to be interim systems while we get the perennial ones up and running. There are issues, and I have much more to say on this, but I can't say it without reference to chapter 7.

I accept that but if ( and its a big if ) we move to a perennial plant solution its not going to happen overnight I would expect an interim period where the less productive ( depending on how you measure productivity ) crops are phased out first .

Comparing potatoes to wheat is perhaps over simplistic. It also makes a great example of why polyculture is so important.

Some places grow wheat well, some grow potatoes well, some grow both really, really well, and some grow potatoes well but then the soil get a blight and they have to stop growing potatoes, or perhaps a pest or disease descends on the grain? These two crops grow at different times of year and have different water requirements.

Potatoes and wheat have different nutritional profiles. Some people can't digest potatoes, others can't eat wheat. Do the studies show the nutritional profile grain grown in a pre-industrial or permaculture way, or are they using modern varieties which have less nutrition? Do they compare traditional preparations of grain (which make far more nutrients available to the eater) or is it using modern ideas on how grain should be grown and processed?

If we are talking of a subsistence farming family of 8, when we say they should grow potatoes, have we taken into account that potatoes do not provide good building or textile material? Straw can be hats, baskets, cooking fuel, rain clothing, coats, shoes, roofs, rugs, mats, ropes, cob.... and a very long list of other uses that we seem to ignore in the 'modern world'. If we tell this family to stop growing wheat and grow potatoes, then how much more land will they need to provide hats, baskets, cooking fuel, rain clothing, coats, shoes, roofs, rugs, mats, ropes, cob, &c.? How much more expense? Do the modern day studies of carbon sequestration take these traditional, long straw, grain varieties into account and the multiple uses of straw before it's composted? Think of all those thatched roofs and all that straw it took to build it, and how old some of that straw is. I don't know the details on thatching, but I've been told that some of those roofs in England have straw in them hundreds of years old. In Japan at least, when they use to strip a thatched roof and rebuild it, they incorporated the old tatch into the new, so a roof could have straw that was over a thousand years old. But most of the time, they simply built up more thatch on top like most houses in Europe.

I'm not defending wheat, or potatoes here, I think they both have their place and uses.

What I would like to show is that the idea that 2 acres of potatoes is equivalent to 12 of wheat is based on an incomplete analysis. It also seems awfully skewed when I think on my history lessons of grain-based, preindustrial societies and how much land each family had for growing grain. I imagine it must be based on modern day ideas and agriculture.

It seems like every second page Toensmeier says it's not that simple, carbon farming alone isn't the solution, but it will help. I'm paraphrasing. Reading this book, I get the feeling that Toensmeier understands that to say 'we should stop growing x and replace it with y' isn't of any use without first-hand experience farming in that region, or at least of consulting (and actually listening to) people who actually get that dirt under their finger nails.

David Livingston wrote:I accept that but if ( and its a big if ) we move to a perennial plant solution its not going to happen overnight I would expect an interim period where the less productive ( depending on how you measure productivity ) crops are phased out first .

This isn't what you said, but it's where my mind leapt to when I read it.
I worry about moving to a perennial only diet. It does not seem as resilient as using both perennials and annuals.

As one example: If a forest fire rages through my farm, how long until I can regrow my staple crops? Annuals take a year, perennials can take many years to become productive again.

My vision is a combination of annuals and perennials. Even if it's something as simple as alley cropping with big machines, or the old hedgerow and 1 hector fields with more manual labour - let's face it, haven't you ever met someone you think would value from a little land time?

Looking back on history (because it is a pure gold mine for inspiration) at societies that recovered from manmade environmental collapse, we can see that one of the things they did was encourage more labour on the farms, and fewer labour saving devices. I'm not sure how we could apply this to our modern day, but it's an interesting pattern.

R Ranson wrote:

My vision is a combination of annuals and perennials. Even if it's something as simple as alley cropping with big machines, or the old hedgerow and 1 hector fields with more manual labour - let's face it, haven't you ever met someone you think would value from a little land time?

Looking back on history (because it is a pure gold mine for inspiration) at societies that recovered from manmade environmental collapse, we can see that one of the things they did was encourage more labour on the farms, and fewer labour saving devices. I'm not sure how we could apply this to our modern day, but it's an interesting pattern.

My vision is similar, for similar reasons, which is why I said fewer potatoes, not no potatoes.

Part of the problem is that our economic system is contingent on a 7 or 8% reserve army of desperate unemployed, preferably with as many of those as possible being paid as little as possible. This reduces inflation and increases profits. Giving all those people decently paying jobs on farms is incompatible with a capitalist economic system.

There is so much that has to change - not just what we eat but how we produce it and the relationships between each other and the land.

I have more to say (about 3,400 more words to say) but I can't say much of it without reference to chapter 7. I'm going to leave it until I understand properly what I can say and how I can say it.

It seems difficult to get people to even discuss perennial-based diets, forget about presenting any plausible models of such a diet. If we can't devise and model diets based on these other crops, how can we encourage a shift in farming practices toward that style of diet?

Regarding loss of perennial crops to disaster - historically, it has been annual crops which have fared the worst in disaster; famine is a feature of agricultural, not horticultural, societies. Also, it seems to me we could design food gardens and farms to be more resilient to natural disaster. For instance in my region there used to be various native edible tuber and bulb things which were adapted to prairies fires. Maybe some of these could be adapted to a perennial-based diet.

In some ways I look at it as a positive thing - a way to develop whole new cuisines. It's something I have on the back burner, as it were, but I can see a market for cookery books. Martin Crawford already has one, but it involved a lot of non-perennial plant ingredients, and I was not enthused.

Some perennials will better survive a one-year drought, for example, than many annuals, especially if they are drought adapted to begin with. If you want to see what happens to fruit trees in a prolonged one, just look at California, although there are other examples. I'm more concerned with long-term shifts in climate.

Maybe I tend to be natural-disaster-focused living where I do...

Okay, I have moderator approval to post this (thanks, Burra). I've been asked to do a bit of pruning, but here goes.

There is so much in this book that my section reviews are turning into posts similar to the length of many of my book reviews. In part this is where his book makes excites me intellectually. The other side to this is where I disagree with the author.

About three years ago I did a lot of reading on how we might be able to feed everyone while preventing a massive extinction event that might well take humans down with so much else. I ended up getting myself tied up in intellectual knots that I still haven't been able to untangle: it was clear even then that doing so was not going to be simple and would require massive changes to what we eat and how we grow it. Toensmeier has a single goal – carbon sequestration. I recognise there are more complex issues at stake, of which the reasons for carbon sequestration (a liveable planet) are among them. Arguably the biggest problem with this section is that the author examines the annual, perennial and livestock systems in isolation, rather than examining them in the context of each other and other planetary (and less so social) needs.

My main interest in terms of permaculture lies in perennial polyculture, which appears to me both to be the epitome of the practice, as well as being the most efficient means of sequestering carbon. Four problems present themselves:
1) Perennial cropping systems take time to mature – five years to decent yields is a reasonable rule of thumb. This means that someone planting a homegarden, whether tropical, subtropical or temperate, requires an interim food supply while the woodland matures.
2) The strong possibility of us hitting some form of tipping point (https://en.wikipedia.org/wiki/Tipping_point_(climatology)) followed by abrupt climate change may make the retention of annual cropping systems a sensible precaution for food security. Annual species have shorter reproductive cycles, making the plant breeding process considerably shorter than with most perennials, and non-native species may be carefully selected in order to replace those for which the climate may have become unsuitable.
3) The abysmal state of research on yields from temperate and subtropical homegardens (what we usually call forest gardens) means that there are little good data on how many people can be fed on given areas of land. This will, of course, depend on many factors, the most obvious being soil, climate, design and species selection and relative dominance, but there is a critical need for this research to take place: it is my opinion that the ongoing failure to do this amounts to near-criminal negligence. There are a range of factors influencing decisions to use any of the practices outlined in this book, but I think we need to be thinking very carefully about land use, and in particular land use efficiency. There are practices that are clearly inefficient, such as feeding grain to livestock, which Toensmeier talks about and comes down firmly against, but there are too many for which we just don't have enough information.
4) This leads to a massive problem about the simple feasibility of moving from one practice to another: much will depend on local knowledge, local conditions and research that is in the early stages or that just has not been conducted.

Whether annual systems are going to be a permanent feature of the agricultural landscape or merely a transitional state in the direction of perennial systems remains unclear to me. I am interested in the integration of hedgerow systems with annual polycultures, both as a means of producing food and as windbreaks and shade from intense sunlight in some (I'm thinking Mediterranean, but the principle is probably generalisable elsewhere) climates. In this case, I'm interested in plants that exhibit reverse leaf phenology (where they leaf out in the dry season – see p. 75), but I'm concerned that these are species likely to become invasive (thus defeating the avoiding extinction criterion).

Can strip intercropping be modified to provide windbreaks and shade for annual polycultures, thus improving yields while sequestering more carbon, if less than might be expected than with perennial polycultures? It seems to me that the answer should be yes (this is basic agroecology), provided the horticulturalist can work out how to avoid nutrient competition and produce enough protein. It should be possible to calculate the proportion of land required for pulse and grain crops in a system to meet human requirements, but more research may be needed. This is one such study, which invites replication efforts: http://balkanecologyproject.blogspot.co.uk/2016/05/perennial-polycultures-biomass-belt.html

It also seems relevant to address the question of yields against primary productivity. Where cattle are grazed, native grass species are replaced with grass species with higher net primary productivity (Toensmeier's “better-quality pastures” (p.86): and we are then often told that this is the same as prairie; an evident fallacy). Carbon sequestration levels remain low. Perennial polyculture systems take time to mature, as we've seen and, while net primary productivity is high, as are rates of carbon sequestration, yields remain a near-unknown quantity, and good design may be key.

It's well known that the highest rates of protein yield per unit area of land are produced by hemp (Cannabis sativa) (also an excellent fibre crop) and the soya bean (Glycine max) (which also fixes nitrogen) – there are dozens of varieties which have not had their genomes fiddled with by the agri-pesticide corporations, and which often have better flavour, better regional climate adaptation and greater aesthetic appeal than the mainstream ones. Monoculture soya beans, as with monoculture anything else, present their own problems but they, along with other beans and grains, present opportunities for the development of annual polycultures, either permanently or as part of a transition to perennial polycultures. Trials incorporating this, SRI (pp. 70-71) and regenerative organic (p. 71) seem to be called for, and may close the yield gap between regenerative organic systems and conventional farming (see p. 71).

Yields are the thing that most bothers me about all the systems outlined in this book. We're going to have about ten billion humans to feed by 2050, absent some major disaster that would wipe out hundreds of millions or more. I admit I'm having great difficulty making the numbers add up. Conventional farming typically has higher yields, although some perennials found in the tropics do approach these. That requires massive (and unsustainable) inputs. Most of the systems discussed in this book, including the temperate homegarden, have lower yields and take several years with minimal yields before maturity.

I respect Toensmeier's view (p.86) that there may be a difference between experience and theory as regards soil formation under grazing regimes. The problem is the nobody appears to be consciously controlling the variables, having followed up Toensmeier's references and others but, given what we do know about carbon sequestration, grazing appears to be counterproductive in all cases. In those cases where minimal quantities of carbon are sequestered, this seems to be the result of other practices, such as the use of cover cropping, no-till systems, tree planting (all of which appear to sequester more carbon where livestock are absent) or the use of external inputs such as compost (a scarce resource, probably better used elsewhere) or supplementary feed (often imported, with the usual levels of energy conversion efficiency: I mean Savory and Salatin, among others). One study cited did find moderate levels of sequestered carbon, but this required the planting of fodder trees – and it's no secret that trees sequester carbon: that's about trees, not cows: the carbon sequestration occurs in spite of, not because of, the grazing. Those fodder trees were Leucaena: a highly invasive species, as likely to make land unusable while having adverse consequences to the ecosystem.

I'd be interested to learn of any exceptions to this rule. Toensmeier calls for research into conditions where grazing sequesters carbon. In the case of homegardens we have some idea about primary productivity (and thus carbon sequestration): in the case of grazing we know about yields, but much less about best practice – if there is such a thing given the alternatives – in terms of carbon sequestration.

Is there a place for any livestock moving forward? I don't want to say maybe, but that's where the evidence leads. If so, however, we're not talking much. There are complex policy decisions to be made where traditional pastoralist communities in much of the Global South are concerned, and I don't want to get involved in a discussion that needs to be taking place between those communities and those policy makers. I'm interested in this from a Global North permaculture farming and by implication diet perspective.

I can work out how to close the gap, and these are not new ideas. Reducing waste in the system is critical; we throw out too much food, and processing is part of that. Paper after paper emphasises a shift down the food chain (this summarises what I think is the most recent one, but they come out quite regularly: https://theconversation.com/can-we-feed-the-world-and-stop-deforestation-depends-whats-for-dinner-58091). According to the study cited here:

Of all the variables involved, the feasibility of feeding the world with no deforestation is more dependent on what we are eating, than on how well we farm. “The only diet found to work with all future possible scenarios of yield and cropland area, including 100% organic agriculture, was a plant-based one.”

I think it's important to factor in the fact that we are losing arable land at a very frightening rate: http://www.globalchange.umich.edu/globalchange2/current/lectures/land_deg/land_deg.html, some of it to bad annual cropping practices, some to overgrazing. We need to factor in the extinction rate, and the need to address that. There is the simple fact that a disrupted climate seems likely to result in regional crop failures.

I still can't make the numbers add up, except perhaps in a best-case scenario. I don't see how to head off mass extinction and feed everybody. Just how big the gap between feeding everyone, staving off mass extinction and the related question of halting the climate crisis actually is isn't clear – there isn't enough information – but it's pretty clear there is one.

Toensmeier mentions mulching as an important adaptation strategy (p. 73), but this seems incompatible with feeding crop residues to livestock (see p. 91) (and indeed with the suggestion for using it for biofuels): we may have to make a choice. Given that ruminants can obtain no more than 50% of their diets from crop residues (i.e. mulch) (his figure), and the other half has to come from somewhere (land-inefficient grazing or imported feed) I find it hard to countenance this practice.

The integration of livestock seems to have one major advantage, but this only applies from one perspective. The System of Rice Intensification (see pp. 70-71) is extremely labour intensive. Grazing has higher yields per unit of labour. From a capitalist perspective, this is a good thing: it means more unemployed, which forces labour costs down, which means more profit, especially from broad-scale agriculture. For the rest of us, more labour-intensive systems are a good thing, because it means work. Provided we can avoid some sort of return to serfdom or other forced-labour practices this should be a good thing for most of us.

This goes back to what I said in an earlier thread: addressing the problem of climate change means changing everything, whether we like it or not. I want to embrace that change – not least because I realise that if we don't do it our way, Nature is likely to do it Her way, and we may like Her way even less. Eating much less meat, if any, is simply going to be one way in which we will all have to make do with less. Eating different, and probably a much wider range, of fruits and, in particular vegetables, pulses and grains, is another. I'm going to have to make do with many fewer potatoes, however much that upsets me.

This brings me back to what I think is one of Toensmeier's biggest problems: he is focused (at least in the global North) on us not needed to substantially modify our diets. I am not the first person to observe that whether or not we can feed ten billion humans while addressing all our other problems depends on what's for dinner (see link above). If, and I'm yet to be persuaded of this, there is a place for livestock in a future of farming centred round agroecology, whether permaculture or otherwise, it seems clear to me that it's going to be a very small place, perhaps as draft animals: meat, and by implication eggs and milk products, are likely to be rare treats. My parents kept chickens, and kept the compost pile in the chicken run, but my compost has always been turned by hand. Little else grew in the rest of the pen: this may have been an overstocking problem, although I do remember discussions on this question, but I do know that chickens scratch.

There are two broader questions, neither of which have clear answers. One relates to which is the best use of land, as regards sequestering carbon. The other is whether annuals provide superior food security in a disrupted climate. The loss of one annual crop would be bad enough: the medium-term loss of a perennial one would be worse. The answer to that would depend largely on whether we were talking about a one-year incident or a major change in climate patterns over a longer period.

As Toensmeier points out (p. 89) livestock can be fed on slopes unsuited to tillage – which is a reasonable argument until one considers the use of no-till systems, contour hedgerows, swales (on or off-contour) and terracing. Where I come from these are often soils that have been heavily degraded and with such poor water-infiltration rates (as a direct result of grazing) that they are linked to substantial downstream flooding with the consequent economic losses and human misery (http://www.monbiot.com/2013/05/30/sheepwrecked/ and also http://www.monbiot.com/2015/12/08/a-storm-of-ignorance/ - the lessons seem clear: stop grazing and start foresting) that continued grazing seems strongly contraindicated, especially with climate disruption likely to lead to more intensive storms (http://earthobservatory.nasa.gov/Features/ClimateStorms/page2.php). These are precisely the places I think we should probably be considering either reforesting or finding other means of improving water infiltration.

In short, all three systems have problems that need to be addressed, with some urgency, and there will be tradeoffs between the relative implementation of each one. I don't see how to make livestock systems work, except on a very small scale, possibly, but there are questions about both annual and perennial systems that need to be overcome.

What I found particularly interesting, after that headache, was the Introduction to Species (Chapter 10). I'm aware that the life involved in smallholding can be pretty repetitive, and I'm keen to find ways to keep my brain active. I've already touched on research opportunities, but opportunities for plant breeding not only could be extremely useful (a perennial bean with the soya bean in its recent parentage, or a perennial buckwheat, would work wonders for both food security and carbon sequestration). Equally, there are undomesticated perennial species that might be open to a breeding programme. A comprehensive investigation of my own regional flora might well turn up neglected species suitable for domestication. I have a short list of suitable plants already, but have no doubt this might be added to.

I find this an incredibly exciting prospect.

We've had endless discussions on this site on the subject of invasive plants. I half agree with Toensmeier on this subject, but there are points where I dispute his position – quite strenuously.

I come to permaculture asking myself several questions, but when you scratch deeply enough it comes down to this:
How do we feed ten billion humans while preventing the worst extinction event in sixty-five million years?

I'm no nativist. I can't even sensibly define the word “native”. I'm all for providing corridors for species to move as a result of climate change, even artificially helping some of them to move. Many of the crops in my garden have no relatives growing in the region. I have nothing against growing non-native species. Toensmeier argues that

“Will it help to reduce emissions, sequester carbon, reduce the amount of tilled cropland? These are the questions we should be asking rather than “Where does it come from?” and “Does it belong here?””

Actually, I agree, but I want to add one, which he skims over but fails to properly address:
Does it cause ecological damage? Is there a tendency for it to become a monoculture, squeezing out other species and those on which those species depend? This is, at root, why around ten per cent of the species listed in the book are also listed in the Global Invasive Species Database (http://www.iucngisd.org/gisd/).

Toensmeier argues (and it's not the first time I've seen this argument) that

“Even in Hawaii, where 100 flowering plants have gone extinct and 1,000 new plants have escaped cultivation (or otherwise arrived) and joined the flora since human arrival, ecosystem functions continue.”

This is all true, but those 100 species have most probably gone for ever. E. O. Wilson, one of the world's top ecologists, points out (and again I've said this elsewhere):

The Hawaiian archipelago, like the equally far-flung Easter, Pitcairn, and Marquesas archipelagoes, deserves mention in part for what it once was. Its tropical climate, relatively large size, and mountainous terrain with multitudinous habitats promoted the genesis of a large diversity of land-dwelling plants and animals. A high percentage of these originated as products of adaptive radiations. Dramatic examples of such species swarms include the honeycreepers among the smaller birds, tree crickets among the insects, and lobelias among the flowering plants. The beautiful assemblage has been largely wiped out or pushed into the remote uplands of the central mountains by agricultural conversion and semiwild gardens of invasive species. Perversely, the latter have become a poster child for the “novel ecosystems” celebrated by Anthropocene supporters."  Half Earth: Our Planet's Fight for Life, 2015 (my emphasis)

This is a far-different characterisation to Toensmeier's.

The thousand are all, as far as I know, thriving elsewhere: actual global biodiversity has declined. This is only one part of a much broader picture of a rate of extinction at least a thousand times greater than the background rate. It is also true that one of the other reasons for such a high rate of extinction is because of the kinds of land use changes we want to avoid: I do not oppose the introduction of non-native species, but I do think it's important to understand the implications for organisms that have evolved relationships with native ones, and I think it's even more important to consider the environmental impact a minority may have if they get through the hedge, or what may happen if the deliberate circumvention of biosecurity measures results in the introduction of a disease (think of sudden oak death in North America (and, increasingly, elsewhere)), ash dieback in Europe and avian malaria in Hawaii. All of these suggest to me that biosecurity measures may need to be more stringent, not less.

For example, the author raves about Leucaena leucocephala as a crop for intensive silvopasture (p96) (the success of carbon sequestration in silvopasture systems may be contingent on it) and also discusses it as biomass (p248) but, if you were to only be interested in its silvopasture potential you might be unaware that

“This thornless tree can form dense monospecific thickets and is difficult to eradicate once established. It renders extensive areas unusable and inaccessible and threatens native plants.” - GISD: http://www.iucngisd.org/gisd/100_worst.php

That does not mean it should not be used at all but that it, like many similar species, should probably remain where it is.

In conclusion, there is some really good material in this book, but I keep finding key – often related – weaknesses in it.

My comment about Potatos and wheat is an historical one from Ireland before the famine And what was also an warning against what can happen if you over reley on one crop . Just as a note the population of Ireland was 9 million in 1811 today it is less than 5 million . Makes the current refugee chrisis in Europe look a bit silly frankly .
David

If we're used to eating potatoes, can we choose from a number of perennial species which might be analogous to potatoes in the diet - starchy, (relatively) high in calories, easy to cook? Is this kind of information presented in the book?

Tyler Ludens wrote:If we're used to eating potatoes, can we choose from a number of perennial species which might be analogous to potatoes in the diet - starchy, (relatively) high in calories, easy to cook? Is this kind of information presented in the book?

Okay, two points.

1) I was using the potato as an example. The problem with potatoes is that they, like many other crops, require you to till the soil. It's not that potatoes are somehow inherently bad for the soil so much as that tilling results in a loss of carbon to the atmosphere.

2) Yes, to a point (chapter 12 on Basic Starch Crops), but most of those are not suited to low temperatures. For example, the air potato (Dioscorea bulbifera) is hardy only to about -6C (20F). I'm not sure if this plant would even thrive in a Mediterranean climate because it has a separate cold and dry season.

I guess a temperate perennial potato equivalent might be the chestnut.

Tyler Ludens wrote:I guess a temperate perennial potato equivalent might be the chestnut.

The problem with that is yields.

I should probably refrain from commenting or asking questions in these threads, since the answers are probably in the book.

Tyler Ludens wrote:I should probably refrain from commenting or asking questions in these threads, since the answers are probably in the book.

I say ask away.

I like your questions, and if the answer is in the book, then we can see what Toensmeier has to say and we can chat about it. If it's not in the book, we could speculate where it fits in to carbon farming as T-- sees it.

Also, if I was an author, and I knew that there was a public discussion group about a book I wrote, I would probably be lurking to see what questions people have so I would know what to put in my next book.

Neil Layton wrote:

Tyler Ludens wrote:I guess a temperate perennial potato equivalent might be the chestnut.

The problem with that is yields.

I guess I'd like more details about this. What are the yields of chestnuts versus potatoes by land area?

Do perennials typically yield less than annuals by land area?

Tyler Ludens wrote:

Neil Layton wrote:

Tyler Ludens wrote:I guess a temperate perennial potato equivalent might be the chestnut.

The problem with that is yields.

I guess I'd like more details about this. What are the yields of chestnuts versus potatoes by land area?

Do perennials typically yield less than annuals by land area?

Potato (Solanum tuberosum) - 5.3 tonnes/hectare (metric) (global average)*
Air Potato (Dioscorea bulbifera) 0.3-5.1 tonnes/hectare (dry weight)
Chestnut (Castanea spp) 1.3 tonnes/hectare (global average)

This is an example of the sort of yield problem we face. In theory, the fact that you can grow multiple crops on the same land should make up some of the shortfall, but we are lacking data, especially in temperate zones, for how to do this.

To complicate matters further, it's possible to financially compensate a farmer for reduced yields during a transition phase but, if we assume we're going to convert even 1% of global crop land to perennials every year between now and, say, 2050, and it takes several years to maximum yields, we're going to lose a couple of percentage points of the global food supply during the transition. This might or might not mean absolute shortages, but it will mean higher food prices, and many poor people are on the edge - or skipping meals - already. The alternative is less waste in the supply process.

* Toensmeier's stated global average is less than his stated range

Neil Layton wrote:we assume we're going to convert even 1% of global crop land to perennials every year between now and, say, 2050, and it takes several years to maximum yields, we're going to lose a couple of percentage points of the global food supply during the transition.

Will grains continue to be fed to animals during the transition, or will the grains that would have been fed to animals go toward making up the shortfall caused by transitioning to perennials?

Does that question make sense?

Tyler Ludens wrote:

Neil Layton wrote:we assume we're going to convert even 1% of global crop land to perennials every year between now and, say, 2050, and it takes several years to maximum yields, we're going to lose a couple of percentage points of the global food supply during the transition.

Will grains continue to be fed to animals during the transition, or will the grains that would have been fed to animals go toward making up the shortfall caused by transitioning to perennials?

Does that question make sense?

Toensmeier argues that we need to stop feeding grains to livestock. This is one of many points he and I agree on.

I also feel feeding grain to livestock is an unnecessary action. The environmental and idea that these grains could give more calories to people aside, very few livestock thrive on a grain heavy diet. In my experience, animals like sheep only require grain in the fall and spring, and only if they are 'working' as in getting ready to or are about to lamb, or heavy lactation. Given the expense of the grain plus the extra expense of dealing with the health issues it can cause, I don't understand why it would be a 'standard diet' to include grain for most animal feed. I haven't read chapter 7 yet, so I'm looking forward to seeing what Toensmeier's solutions are.


The yield numbers of weight per hecter given earlier - what does that look like in terms of nutritional profile? So, if chestnuts had a higher nutritional profile than potatoes, maybe the 1.3 tonnes would be worth the 5.3 tonnes the potatoes give (as an example, not accurate numbers)? Do these crops offer anything else to improve the standard of living (like straw, firewood, &c)?

I find it very complicated to compare crops like this. I think that people in the 'west' have forgotten that most plants grown have a multiplicity of uses in a situation without modern globalization. I can see the use of this kind of comparison, but the more I try to say one crop produces more, or is better than, or is more nutritionally dense than.. the more I realize that polyculture is the path for me. It makes no difference that potatoes produce 5 times as many tonnes per hectare than chestnuts, if potatoes don't grow well for me, or if I have a crop failure. But if I grow some potatoes, some squash, some nuts, some of something else, maybe two out of three crops will fail, but I'll still have enough to eat.


By the way Neil, I am still reading your big long post (I haven't had more than a minute at my computer in one go today - oh what a busy day, but I got some practical hands-on experience on how plumbing works - that was 'fun', but the water is back where it belongs and not in spewing in exciting new directions. Once I have my chores done, I'm looking forward to giving your post my full attention). I'm enjoying a lot it so far. Haven't got to the end yet, so I'll leave my comments on it for later.

Reading chapters 6 (annuals), I discovered some great ideas. The style of growing rice, in particular, was very interesting as it used less water and seed, but got double to four times as much as modern paddy farming. On the other hand, it takes more labour, which might not be such a bad thing.

The reoccurring theme seems to be that we already know many of the methods we could adapt, and these seem to work, however, what we really need is a cultural shift.


I was very disappointed that hedgerows only got three short paragraphs (with luck there will be more about it later in the book). Up to the middle of the 20th Century, many rural places in Western Europe still relied on hedgerows for a large portion of their diet. Even in Suffolk, where my dad grew up, it was common to get 25 to 75% of their food from hedgerows, not to mention fuel, building supplies, gardening supplies, and all the other benefits that hedgerows provide to the crops such as wind protection, boundary, home for pollinators and predatory insects, ad infinitum. A hedgerow wasn't planted and left, nor did it happen on its own. It was planned and carefully tended. All these things described as being provided by a homegarden or foodforest, the hedgerow did most of it AND provided other benefits. Earlier in the book, it was mentioned that there weren't enough examples of temperate homegardens. I submit that if we change our view point to look at hedgerows as "multistrata agroforestry system", that we may discover a traditional temperate homegarden, only in a different form.

I admit, there aren't many people left alive who remember what life was like before the modern time, but there are a few. Have we really forgotten how vital they were to sustainable agriculture in the past?

In general, annuals produce more then perennials, since they only have on shot at it. However, perennials provide more valuable biomass (wood.) So a few acres of chestnuts can heat a house as well as providing food, while you would be hard pressed to heat a house with potato tops.

Annuals are ideal for dealing with tough situations, such as climate change, migration, war aftermath, severe weather, and harsh climates. For instance, in my climate, trees don't bear fruits and nuts reliably; late spring frosts following 80 degree days tend to destroy buds. Trees are not native here. But grasses of various sorts grow well; my rye is 5 feet high with no watering.

Maybe not potato tops, but I am experimenting this year with dry amaranth and sunflower stems. There is folklore that these kinds of sunflowers are used for cooking fuel. We played around with the amaranth last year and it was lovely. They burn hot and fast, so no good for an open fire or modern day woodstove. But perhaps with a rocket mass heater...? I don't have a RMH yet, but I just finished my rocket cookstove. I figure if they can work for that, then they would be a viable source of fuel for heating the home.

I know burning releases carbon back into the atmosphere, but perhaps if these sunflowers were grown for their oil and seed crop anyway, the leaves could be used as mulch/compost, and the stems burnt as cooking/heating fuel. That would reduce the dependence on coal, electricity or burning trees. Would that be a viable step towards a kind of carbon farming?

Neil Layton wrote:

I'd be interested to learn of any exceptions to this rule.

Liquid carbon pathway unrecognised

Interestingly, the growth of an annual crop direct-drilled into perennial pasture can be equal to, or better
than, the growth of an annual crop planted alone

More food

Under appropriate conditions, 30-40% of the carbon fixed in green leaves can be transferred to soil and
rapidly humified, resulting in rates of soil carbon sequestration in the order of 5-20 tonnes of CO2 per
hectare per year.

More carbon

Permaculture is the exception to the rule.

Edited to add: To learn more PASTURE CROPPING: AN INTEGRATED APPROACH TO GRAIN AND PASTURE PRODUCTION

Are there any numbers on the amount of land that needs to be carbon-farmed to offset the carbon produced by carbon-farming with petroleum-powered farm equipment? For instance, if one is growing an annual crop drilled into perennial pasture, how many hectares grown this way are needed just to offset the tractor used to plant and harvest the annual crop?

Tyler Ludens wrote:Are there any numbers on the amount of land that needs to be carbon-farmed to offset the carbon produced by carbon-farming with petroleum-powered farm equipment? For instance, if one is growing an annual crop drilled into perennial pasture, how many hectares grown this way are needed just to offset the tractor used to plant and harvest the annual crop?

Sure there are numbers. Using the numbers from the above source:

There is somewhere between 35 and 40 Gt CO2 emissions yearly worldwide. To draw down CO2, (decrease the stocks in the atmosphere) we must adjust the flows into and out of the atmosphere until we achieve a net negative flux.

There are approximately 5 Giga Hectares of land in the world currently being used to produce food for human populations. (only ~1%+/- is in permaculture or other ecofriendly management) Agriculture has been proven to be capable of being an emissions source or a sequestration sink depending on the methods used. Currently right now agriculture is an emissions source. (99% being managed by either industrial or traditional subsistence methods)

Working backwards, for agriculture to offset emissions and achieve a net negative flux for atmospheric CO2 worldwide each hectare of agricultural land producing food would need to sequester long term into the soil over approximately 8t CO2/year. 8t CO2/ha/year X 5 Gha = 40Gt CO2/year

The case studies mentioned by Dr. Christine Jones above show a range in results between 5 & 20 tonnes CO2e/ha/year increases in soil carbon by using permaculture pasture cropping methods. (direct seeding grain crops into perennial pasture and cell or pulse rotational grazing integrated together)

So not only would it offset the tractors use, also quite likely if done on enough land, offset between 62% and 250% of all emissions worldwide. That is VERY conservative BTW, because it doesn't even include the oceans or the forests which already are removing about 1/2 of the ~35 to 40 Gt CO2 emissions yearly worldwide. So we have some wiggle room to do other things beneficial to the environment if we were to switch to a 99% permaculture world instead of a 99% industrial and subsistance world.

I'm sorry, I'm very dense, but I'm not seeing the specific answer to my specific question: how many hectares grown this way are needed just to offset the tractor used to plant and harvest the annual crop?

If I'm growing 10 hectares of corn drilled into permanent pasture, for instance, how many hectares are needed just to offset the use of the tractor?

Thanks.

Besides, who says it has to be a tractor? What about a horse drawn drill? Or a human powered jab planter?

I'd just say that 10,000 years of work has went into annual crops, and we shouldn't just dump them now; they are a useful component of a permaculture system, just as they are in nature.

Tyler, I like this question.

Is it really such a small amount as one acre? Tractors are pretty resource heavy to build and transport, travelling through several countries during manufacturing, from raw material to farmer. Then there is upkeep and fuel, and oils, and damage done to the soil by the pure weight of the tractor, then size of tractor vs, it's suitability to the land (wrong kind of tractor for the land costs more resources to run and maintain) and size of land, &c. Factor those over the life of the tractor, take into account the accessories, then the disposal/recycle of all of this. I think it would be a pretty complicated calculation. I wonder how many acres it would be.

R Ranson wrote:Tyler, I like this question.

Is it really such a small amount as one acre? Tractors are pretty resource heavy to build and transport, travelling through several countries during manufacturing, from raw material to farmer. Then there is upkeep and fuel, and oils, and damage done to the soil by the pure weight of the tractor, then size of tractor vs, it's suitability to the land (wrong kind of tractor for the land costs more resources to run and maintain) and size of land, &c. Factor those over the life of the tractor, take into account the accessories, then the disposal/recycle of all of this. I think it would be a pretty complicated calculation. I wonder how many acres it would be.

That's why originally I answered in total emissions from everything world wide. But just to answer the question of running the tractor. ~ in the range of .001 hectares of land or less to offset the fuel used to run the no till drill on 10 hectares producing grain using the permaculture method of pasture cropping.

Scott Strough wrote:

Neil Layton wrote:

I'd be interested to learn of any exceptions to this rule.

Liquid carbon pathway unrecognised

An unreferenced article in a presumably predatory journal that no longer even exists.

Credibility level - zero.

The relevance doesn't seem to be much higher. I'm struggling to find where it says what you say it says (not, as I say, that it matters because, in terms of scientific credibility, it's junk).