Is there any strong factor against human edible plants being widespread and easy to gather?

While many habitats have plants, fruits, nuts and berries available for consumption by humans walking by, most places (if any?) seem to require significantly more effort than simply picking our food from trees and bushes in order to survive.

Borrowing @BryanKrause's words in a comment below:

"Why don't you find enough things like broccoli, green peppers, almonds, and wheat to support a human population when you are walking in the woods/natural fields?"

Define "easily available to human", lots of fruit are perfectly edible to humans. Human have only become widespread in the last few million years so there is not enough time to see things specialized in humans via natural selection. Especially since we are both generalists and for most of the world completely new factors in the environment.

But there are plants that have evolved to be eaten by humans. Wheat, rice, and, maize have done amazingly well by having the right factors to be useful to humans, they are also some of the most common plants on earth now thanks to us. Artificial selection is still evolution, it's just not natural selection. Humans are generalists and its hard for natural selection to push things to specialize in edible symbiosis with a generalist, especially in as short a time as humans have been around, but artificial selection can do it just fine becasue it is faster, provided the plant in question survives us long enough.

Being useful to humans is also a bit of a mixed bag sometimes it means we spread you over the whole world, such as wheat and dogs, but sometime is means harvesting to extinction like Silphium. Then you have things like avocado which almost went extinct becasue humans killed off their parter animals and almost nothing else could eat them, then we invented farming and decided we liked them and brought them back from the brink. Human intelligence and cultural information sharing means capabilities and technology change so much faster than the speeds natural selection tends to work at, most things just have not had the time to really adapt to how fast we changed the world, unless we take an interest in forcing them to.

Humans prefer the very tenderest of plants as found in shops, which only grow abundantly when there is a lot of rain and warmth: salads, roots, tubers, fruit. Other animals are not so fussy, they have more stomachs and more grinding teeth. So plants that are palatable to humans have very few chemical and physical protections, and are good food for all herbivores. That's why the majority of plants have chemical and physical defenses, cellulose that makes them stringy, hair, tannins and so forth. plants favored by humans are favored by insects and mammals too. harsh habitats that favor slow growth have very few fast growing and low cellulose plants, i.e. mediterranean, where everything is strawy and has spines and strong resins. In cold habitats, juicy low cellulose plants can't grow fast enough to gain advantage by rapid low cellulose growth. In arid habitats, insects and animals covet juicy salad type plants, and they are eaten fast and also grow slower. Only in lush green habitats, i.e. tropics and in temperate climates can indigenous people go for a 10 minute walk and bring home malva, palms, thistle stems, reed roots, vine, and make a salad in a very fast time.

What are the implications when we find out that EVERYTHING is conscious?

I don’t eat meat or animal derivatives, but one plane of thought I’ve had inside and never really discussed with anyone, is what veganism would mean if we acknowledged that everything is conscious, including trees and plants, and that they just express it through a means that is not identical to animals (including humans because we are what is defined as an animal). There is more and more research being conducted on the sentient nature of trees, and how they communicate and prefer to send nutrients through soil to ‘family’ trees. There is much more information out there which you can find. And then of course there is the ‘consciousness problem’, in which we have no clue where and when consciousness begins to exist within matter (e.g. a human body), and that many scientists studying and philosophers debating this topic end up finding themselves believing that consciousness may be an innate feature to all matter.

I define myself as a vegan but I have a job as a Gardener and I am here on some days cutting away at a tree with a chainsaw because a lady wishes for her garden to look more aesthetic. I am not saying that for certain that everything is living and conscious, but I think it’s possible. Just keep this question in mind and go walk outside in nature, and you may be surprised by what you feel.

I want to know what others opinions are on this. If we did assume everything was living and having some sort of an experience, what would veganism evolve into?

I'm predominantly an egoist and find that the vast majority of human behavior is motivated by social contracts and self-interest. Convince me that veganism is compatible with this worldview.

Any human action can be traced to perceived self-interest. This ranges from working at a job to jumping in front a bullet for a loved one. We seek to minimize guilt and negative emotions and maximize our social standing and positive emotions. The reason why this is compatible with groups is because humans are a hyper-social species that form social contracts, causing self-interest to manifest itself in the form of seemingly altruistic behavior.

Humans are not evolved to care about everyone equally. It is well established that proximity is a major factor in moral consideration, regardless of culture. The more connected a person is to the self, the greater their moral consideration. This is in line with the way we have evolved, working in small tribes collaboratively to survive. Capitalism is also built on egoism. People work to pursue their own self-interest and thereby create economic value. Basically every successful country operates on a free market with the protection of certain rights. They might have social programs, but they are still free-market oriented. The denial of egoism even proves its own validity: people don't preach it in person because it makes them sound selfish, reducing their social status. That itself is an act of self-interest. People preach altruism, but live on egoism.

Simply put, humans are self-interested like any other species, but the difference is that their self-interest can work for the benefit of each other. Social contracts are so powerful that they have been enforced in the form of laws. We respect the rights of life, liberty, property, and more, because others respect it back, or at least might potentially. But when someone does not respect those rights, such as a serial killer, a thief, or someone who voids a transactional contract, we defer to the law to compromise their rights in return.

The problem with (most) animals is that they can NEVER respect human rights and social contracts. A pig would gladly walk into your house and eat out of your fridge without your permission, if it could. A chicken will bite at you for coming near its living space. Spiders live in your house whether you want them to or not, and will even sometimes try to kill you if you attempt to remove them.

If we were to extend animals human rights (most, anyways), we would be engaging in a one-sided social contract.

We still care about harming some animals for other reasons. For example, killing your neighbor's dog is wrong because you have a social contract with your neighbor. Even if you didn't, killing the dog would remind you of killing an animal that is protected by a social contract, such as your dog or someone's you know, and thereby invoke a negative emotion (making it undesirable under egoism). If someone saw you kill the dog, then you would break a social contract with them by causing them emotional grief.

Babies do not form social contracts, but like pets, there is a social contract with their parents/guardians, they will grow up to form social contracts (unlike farm animals and fish), and killing them invokes a similar emotion to killing dogs, making killing babies usually wrong under ethical egoism.

If you were to have a human being who had no hope of respecting the rights of others and their social contracts, that person who be so dysfunctional and dangerous that I would have no problem with killing them.

It seems to me that vegans are functionally egoists like everyone else in the sense that eating meat has become a source of displeasure due to (usually intentional) familiarity with animal suffering. In that sense, vegans have made animals higher in proximity. But under egoism, this is not a necessary step, since social contracts can be maintained whether you increase their proximity or not. Therefore, veganism is an optional restructuring of moral consideration and sources of displeasure, and thereby an optional restructuring of what actions are moral under egoism. But it's still optional.

So as far as I'm concerned, vegans are asking people to live contradictory to the way we are evolved and to form a one-sided social contract with and respect the rights of creatures who will never do the same for us. This is entirely not realistic or sustainable and likely explains why most vegans quit. One-sided social contracts should never be a moral obligation, even for other humans. If you had a baby stranded on an island, too sick to age a few months and form a connection, and with no one alive who cared about their existence (including yourself), then sure. Feel free to kill them if it is to your perceived overall benefit. If altruistic behavior makes you happy, then feel free to do so as well. But no one has to. Humans will continue to live on as the hyper-social species they are, pursuing their self-interest. If you want to try to change people's moral consideration and thereby modify what's in their emotional self-interest, go right ahead. But as an ethical egoist who views the world through the lens of mutually respected rights, social contracts, and self-interest, I maintain that they are not morally obligated to comply.

Edit: this post has flared up more than I expected. Probably won’t have time to respond to everyone, but I’ll do as many as I can.

Accepting other peoples choices - a hypothetical what if?

I'm not a vegan but I share many of the goals, especially around environmental concerns, and the majority of food I eat is plant based.

One aspect of the debate here that's surprised me most is the lack of tolerance for other people who make different choices as to how to reduce suffering or help the environment. I understand why veganism and (for example) vegetarianism are incompatible, but given that veganism has relatively low take up across the world, Iɽ have thought the pragmatic route is to support and encourage any and all activities that get somewhere close to the goal.

So, a hypothetical scenario. You try to convince your friend/family member who is not vegan to give up meat. They refuse, but as a compromise, offer to reduce non-vegan consumption to 25% of current levels for the rest of their life, contingent on you never mentioning veganism to them ever again.

Do you accept? If not, why not?

To avoid any doubt, let's be realistic about the probability they would later agree to veganism - maybe 1% of the world are vegan, so even if you're very good, your conversion rate won't be more than 10%.

I agree with the spirit. Compromise if we can't achieve the ideal, but I don't think that should always apply.

When we look at other social issues we start to run into some strange things.

"I don't want to give up slavery but I'll reduce the number of slaves I own by 20%"

"Child labor is just so cheap, but just for you I'll replace 33% of them with adults"

"Instead of paying women 70% as much as men we'll pay them 90%"

These are all steps in the right direction, but why can't they go all the way. Is it really that much more difficult to give it up totally versus reducing slightly.

Does their personal choice outweigh their victims' suffering?

They key difference is that we're on the other side of those debates and most people clearly value animals lower than people. They're both pretty big differences - you're arguing with a certainty about the topic but that's all based on the assumption that the world as a whole ever agrees with you, which right now is nowhere near certain.

Your 3 examples all involve people. Comparing people with animals is wrong as we are not equals.

When faced with the reality they can't go all the way, what other options do you have but settle with a decrease?

Veganism is about animals, not a diet.

The environment and health are just "collateral damage".

25 percent of billions animals are still billions animals.

And veganism is still growing.

Veganism aims to minimize harm. Anyone can see you're not going to convince everyone to be a vegan, so in this scenario, accepting the proposal reduces harm.

I would accept it, I can't force them to change. But I wouldn't be happy about it.

To me, veganism is a moral stance. I am a vegan because I think the way we treat animals is disgusting and we have no right to use and abuse them the way we do.

So, people only reducing their intake or being vegetarian isn't good enough for me.

To me it is like saying, "I love my children, I only beat them on the weekends." It just doesn't make sense.

If we were talking about any other movement, a slight reduction in bad behaviour is never going to be seen as good enough. Like imagine a white supremacist saying they're only going to go to one kkk meeting a month, instead of going once a week. This isn't good enough. They're not changing anything. They're still fighting for and supporting the oppression of black people.

This same logic applies to animals for me. Reducing animal consumption is not enough, because ultimately they are still paying for abuse, explotation, and murder. There is still a victim.

An animal is a living being worthy of respect. You can't respect or care about them while abusing and slaughtering them.

Veganism is the bare minimum.

How someone else eats isn't about me. Vegans don't ask other people to go vegan to please us, it's because we want to end the industries that torture and kill animals. We also have no control over how you live your life, and can't make you go vegan if you don't want to. But you can't insist on having someone else's respect either. It's up do me whether I want to like someone or not, or think someone is a good person or not. I don't think non-vegans are bad people, and I generally don't disrespect them as people, but I don't respect people's decisions to participate in animal agriculture when it's completely unnecessary. And if other vegans want to hate all non-vegans, that's up to them.

I want asking for your acceptance. Rather trying to make the point that if you're unable to convince everyone to go vegan, why isn't reducing the world's consumption as far as possible also a goal?

I think the clearest way I can respond with this question is asking you a similar one in turn.

Say you have a friend who is a repeat rapist. You are interested in ethics, and greatly desire for them to stop raping people because of your ethical concerns. Your friend responds that they will stop raping on weekends, but only if you never bring it up again. How would you feel about their response? Is it sufficient to you that they stop intentionally inflicting great bodily harm

I challenge you to meaningfully engage with this, and not simply hand wave it away saying it's "not the same". Of course it's not the same, that is how analogies function. Please respond more substantially than that. I think your honest answer to this hypothetical will likely be the exact same answer I have to yours!

Perhaps to make it more directly analogous, your hypothetical friend is paying for authentic revenge porn, and proposes not purchasing it on weekends if you never bring it up again.

How would you feel about their response? Is it sufficient to you that they stop intentionally inflicting great bodily harm

Assuming I was a "against rape" contrarian in a society where rape was allowed and considered as fine and where everyone was raping all the time, yeah, I guess 75% less rape is better in my contrarian mind than 0% less rape.

Your point? Do you disagree, and do you prefer 100% of rape occurring, or 25% rape?

Interesting example. Let us change a bit and clarify the conditions:

Change: instead of rape, let us say this person is a serial killer (very skilled, will never get caught) and kills someone every day.

Clarification: you only communicate online, you don't know who they are, where they live, etc. You cannot have any impact on them (eg. cannot stop them physically) except through online chatting.

You express your moral objections. They say they will not kill anybody on weekend if you never talk about your moral objections again. So what do you do?

You never talk to them again. After all, your core morals are so different, why are you even talking to them in the first place?

You want to continue to talk to them (maybe you are lonely), but still, you want them to stop murdering people. So this all comes down assumptions and calculations:

If you never mention the issue again, your saved hundreds if not thousands of people (104/year more specifically). You assume the person would continue killing for 20 years, after which they will be too old to be able to kill without getting caught. So that is 2080 people saved.

You think you might have a chance to eventually convince them to totally stop murdering. You estimate that the chance of that happening is 1% a year. That means (with a little probability theory) that you have overall 18.21% that you will convince them to stop murdering sometime during the next 20 years. This means the expected value of lives saved is 653.6. (I assumed the result of your convincing efforts are revealed at the end of every year).

If these assumptions are true, if you stop raising the issue, you will save 2080 people compared to the 653 people you get by trying continuously to convince them to stop murdering. So what would you choose?

Vegan definition?

What is your personal, official definition of “vegan”? I’ve been trying to figure out what my specific veganism looks like and part of my trouble is that many people use the word in many different ways but there’s no formal definition.

an official original definition by The Vegan Society

A current, different definition by The Vegan Society

Other past versions along the way

A more colloquial definition used by many businesses to simply mean “no animal products in this food”

And I’m sure other possible definitions.

I’m just curious what is the most official, specific definition of “vegan”, in your opinion? Thanks!

"A philosophy and way of living which seeks to exclude—as far as is possible and practicable—all forms of exploitation of, and cruelty to, animals for food, clothing or any other purpose and by extension, promotes the development and use of animal-free alternatives for the benefit of humans, animals and the environment. In dietary terms it denotes the practice of dispensing with all products derived wholly or partly from animals." - The Vegan Society

That's the definition. Anything else is people creating their own definitions to fit their own view, but it's not the "real" definition. It was created by The Vegan Society, so they defined it very simply and clearly.

Chickpea Production

This section in the publication is intended for growers considering kabuli or desi chickpea as a crop. The text covers basic plant growth habit, crop production, field selection, seedbed preparation, fertilization, inoculation, seeding, weed control, diseases, insects, rotational benefits and harvesting.

Chickpea (Cicer arietinum L.) originated in what is now southeastern Turkey and Syria and was domesticated about 9,000 B.C. It is an annual grain legume or “pulse” crop sold in human food markets.

Chickpea is classified as kabuli or desi type, based primarily on seed color and shape. Kabuli chickpea, sometimes called garbanzo bean, has a white to cream-colored seed coat with a “rams’s head” shape and ranges in size from small to large (greater than 100 to less than 50 seeds per ounce). Desi chickpea has a pigmented (tan to black) seed coat and small angular seeds.

Before selecting a cultivar, contact potential buyers to ensure it is accepted in the market you are targeting.

Chickpea is a high-value crop adapted to deep soils in the semiarid northern Great Plains. However, disease risks are high, and Ascochyta blight can cause devastating financial losses for growers. Thus, this crop is recommended only for producers who are willing to scout diligently and actively manage disease pressure throughout the entire growing season.

Price Uncertainty

Producers of alternative crops such as chickpea face price volatility in addition to production uncertainty. Chickpea is a high-risk/high-cost crop with potentially high financial rewards. Price uncertainty is a particular challenge with chickpea because it is a small-acreage crop and acres planted can fluctuate dramatically. Harvested acres in North Dakota from 2010 to 2019 are presented in Figure 3.

Figure 3. Chickpea harvested acres showing large (kabuli) and small-seeded (desi) chickpea varieties planted from 2010 to 2019 in North Dakota (2019 planting intention is at the beginning of the season).

Source: North Dakota Agricultural Statistics Service.

Before planting chickpea, knowing where the crop is going to be sold is essential. Because chickpea is a specialty crop, bringing harvested chickpea to the local elevator may not be possible. Therefore, you need to know where to sell and deliver the crop, as well as what the buyer wants.

  • Does the buyer want a specific variety? If yes, buy certified seed because the buyer may require documentation of the seed source, especially if it is a Plant Variety Protected (PVP) variety.
  • What are the quality specifications? In the food-grade market, split seeds, cracked seed coasts, discoloration and greens (immature seeds) can result in steep discounts. Buyers of kabuli types prefer a light and creamy seed color. For these reasons, food-grade chickpea demands careful harvesting, handling and storage to sell for the highest price.

Chickpeas predominantly are used for human food products but also can be used in animal feed. Chickpeas have a wide variety of food uses, including salads, hummus and cooked in stews or curry. Chickpea flour is used as batter for deep-fried meats and vegetables or an ingredient to make flat breads and desserts. Chickpea dishes are widespread in South Asia, the Middle East and Mexico.

Because chickpeas predominantly are used for human food, crop quality and consistency are very important. Price premiums are paid for large-sized seeds, but price discounts often apply for damaged, broken or discolored seeds. Tests for restricted-use crop chemicals often are conducted and a buyer may reject the production if amounts are above the maximum residual levels, or MRLs.

Approximately 65% of the U.S. production of chickpea is used domestically. Major export destinations include India, Europe and the Middle East.


Drought Tolerance

Under drought stress conditions, maturity requirements for chickpea are similar to or slightly longer than for spring wheat. However, chickpea has an indeterminate growth habit, which can extend maturity greatly if cool or wet late-summer conditions persist. Chickpea roots deeper than dry pea or lentil and is more drought tolerant because it can tap into stored subsoil moisture, when available.


Flowering time of chickpea is influenced by photoperiod. Some varieties are highly photoperiod sensitive, while some are not. Some varieties have intermediate response. Fewer degree days are required for flowering in photoperiod-insensitive varieties.


Cool growing season temperatures and early fall frost can prevent chickpea from fully maturing. Chickpea tolerance to frost is similar to spring cereal grains. Chickpea tolerates high temperatures during flowering, unlike dry pea.

Growing Season

Chickpea matures later than dry pea or lentil and prefers a longer, warmer growing season. Desi chickpea typically flowers one day to one week earlier than kabuli, depending on the variety. Large-seeded kabuli varieties generally mature one to two weeks later than desi types, which have been bred for earlier maturity. Average maturity will depend on the variety and climatic conditions, and ranges from 100 to 130 days.

If seeding chickpea in early May, plan to harvest by mid-September. Under cool, wet late-summer conditions, maturity can be delayed substantially due to chickpea’s indeterminate growth habit, and producers must manage to meet market specifications for green seed content (less than 0.5% to receive U.S. No. 1 grade, USA Dry Pea and Lentil Council).

In a year with abundant fall precipitation, chickpea might never fully mature. Under such conditions, a producer should gauge when the crop has fully mature pods from the bottom of the canopy up to the top 25% of the canopy, and then swath or desiccate.


Variety evaluations for North Dakota appear in Table 7.

Chickpea yields range widely in North Dakota. Although some varieties possess some level of Ascochyta tolerance, many varieties have very low levels of tolerance. Even though the desi chickpea market price typically is less than that for large kabuli types, the increased yield potential and lower production costs might result in equal or greater net returns.

Table 7. Chickpea seed yield, at various Research Extension Centers in North Dakota, 2016-2018.

1 C = compound, S = Simple (see photos below)
2 DAP = Days after planting.

Chickpea with compound leaf. (C. Keene, NDSU)

Chickpea with simple leaf. (C. Keene, NDSU)

Plant Growth Habit

Chickpea has hypogeal emergence in which the cotyledons remain below the soil surface and emerge by elongating epicotyl. This allows the seedling to tolerate late spring frost and have the ability to regrow from the below-ground buds, if the top growth is damaged.

Most chickpea varieties have compound leaves that exhibit a fernlike appearance however, a few kabuli types have simple leaves. The chickpea plant is erect, with primary and secondary branching resembling a small bush, reaching a height of 8 to 24 inches.

On average, the plant produces a new node every three to four days, and flowers approximately 50 days after plant emergence, at about the 13- or 14-node stage. The plant flowers profusely and has an indeterminate growth habit, continuing to flower and set pods as long as climatic conditions allow.

Kabuli and desi chickpea types can be identified easily by flower color: Kabuli types have white flowers, indicating the absence of pigmentation, while desi types having purple flowers. The pods are oval shaped, borne singly, and contain one or two seeds. Plant height ranges from 10 to 22 inches, while kabuli types often are slightly taller than desi types.

Flowering desi chickpea variety with compound leaves. (T.R. Stefaniak, NDSU)

Growth stages for chickpea are divided between vegetative and reproductive phases (Table 8). However, because the plant is indeterminate, new leaves continue to develop after flowering begins.

Table 8. Growth stages of chickpea.

Growth Stages
Vegetative Growth Stages
VE Seedling emergence
V1 First multifoliolate leaf fully expanded
V2 Second multifoliolate leaf fully expanded
V3 Third multifoliolate leaf fully expanded
V4 Fouth multifoliolate leaf fully expanded
Vn nth multifoliolate leaf fully expanded
Reproductive Growth Stages
R1 Early bloom, one flower open
R2 Full bloom, most flowers on the plant open
R3 Early pod, pods visible on lower portions of the plant
R4 Pods have reached their full size but still are flat
R5 Early seed, seed in any single pod fills the pod cavity
R6 Full seed, seeds fill the pod cavity
Physiological Maturity
R7 Leaves start to yellow and 50% of the pods are yellow
R8 90% of the pods are mature color (gold to brown)

Cultural Practices – Crop Production

For optimum yield potential and success in chickpea production, give attention to field selection, seeding, inoculation, disease control, weed management, insect pest management, harvesting and crop rotation. Disease management is critical to success.

Crop Rotation

Chickpea, like other annual legumes in a rotation, offers several cropping advantages for the producer. Cereal crop yields often increase when planted after legumes due to the following:

  • Cereal pest life cycles are disrupted.
  • Alternative herbicides can be used to clean up grassy weeds.
  • The soil nitrogen supply is increased.

However, chickpea has a moderately deep rooting system (similar to spring wheat), which is effective at extracting subsoil moisture, and because little stubble remains after harvest to trap snow and minimize evaporation, available crop water can be limited following chickpea in dry areas.

Chickpea stubble is not recommended to be planted to winter cereals because seeding disturbance destroys scarce crop residues and soil moisture often is insufficient to allow good germination of the winter wheat crop.

Field Selection

Chickpea can be planted into small-grain stubble. Chickpea should not be planted in a field that was planted to dry pea or lentil last year. Ideally, the field should not have been planted to pulse crops for at least two years to minimize the risk of root rot.

Seed size is a critical marketing factor for large kabuli types, and production in low-rainfall areas after a low-water-use crop such as flax can help ensure adequate water supply late in the growing season when seed size is determined.

Little information is available for chickpea production under irrigation in the northern Great Plains, but experience in southern Alberta and central Montana suggests it is a viable practice, provided Ascochyta blight is managed successfully. At Sidney, Mont., the average chickpea yield under irrigation was approximately 2,100 pounds per acre in 2017.

To select appropriate fields for chickpea, consider previous herbicide use, weed spectrum and pressure, interval since chickpea was last grown, and proximity to current and past chickpea fields. These considerations are critical to managing weeds and diseases and to reduce the potential for residual herbicide injury to the crop. See NDSU Extension publication W253, “North Dakota Weed Control Guide,” for more information.

Avoid fields that have a history of perennial weeds, such as Canada thistle and field bindweed. Many herbicides used in small-grain production can carry over and cause chickpea injury and yield loss. The rotational interval for chickpea depends on how long herbicides remain in the soil.

Factors that affect herbicide persistence include pH, moisture and temperature. Because western North Dakota has a dry climate and short growing season, herbicides generally degrade more slowly there than in warmer, wetter areas. Sulfonylurea herbicides (Ally, Ally Extra, Amber, Finesse, Glean, Peak and Rave) persist longer in high-pH soils. In areas with low rainfall and high soil pH (greater than 7.5), sulfonylurea herbicide residues may remain in the soil much longer than described on the label, and a soil bioassay should be conducted before planting chickpea.

For integrated disease management, start by selecting a field that has not had chickpea for at least three years and is at least three miles from previous year’s fields. However, even with these precautions, any chickpea field should be considered susceptible to Ascochyta blight during wet periods because long-distance spore transmission appears to occur. Fields that are well-drained are preferred because chickpea can be injured by waterlogged soil relatively quickly, compared with other nonlegume broadleaf or cereal crops.

Producer experience suggests that both types of chickpea can be seeded as early as other pulse crops (dry pea and lentil). Chickpea seed should be treated for soil- and seed-borne pathogens (See NDSU Extension publication PP622, “North Dakota Field Crop Plant Disease Management Guide.”) Using high-quality seed free of Ascochyta (less than 0.3%) also is essential, and seed treatment is recommended as part of an effective plan for integrated Ascochyta blight management.

Air drills and openers often need minor modifications and adjustments to avoid damaging seeds and facilitate metering of large-seeded kabuli varieties.

Chickpea typically is seeded in narrow row spacings of 6 to 12 inches. The target for established plant densities for kabuli and desi types is four plants per square foot (about 175,000 plants per acre). This usually requires planting four to five chickpea seeds per square foot. Depending on seed size, this often translates into seeding rates of 125 to 150 pounds per acre for large kabuli types and 80 to 100 pounds per acre for desi types.

Processors of kabuli types prefer large seeds and often pay a premium based on size. Breeders consider the ratios of large:medium:small seeds when making their selections because seed size has a genetic component.

However, row spacing, seeding rate and, ultimately, plant population also influence seed size. Producers should be careful not to exceed four established plants per square foot to ensure maximum seed size and enhance the marketability of kabuli-type chickpea.

Seeding depth recommendations are 1 inch below moist soil for small-seeded types and 2 inches below moist soil for large-seeded types. Chickpea can be seeded as deep as 4 inches to utilize available soil moisture for germination.

If the field requires rolling, the operation should be completed immediately after seeding or after the plants are well emerged but before the six-leaf stage of growth. Avoid rolling during plant emergence due to increased risk of injuring plants.

Symbiotic N-fixing Bacteria

A common requirement for efficient production of chickpea is inoculation with specific N-fixing bacteria. Chickpea requires an inoculant with the bacteria Mesorhizobium cicer. This species of rhizobium is unique to chickpea. The rhizobium used for field pea and lentil will not result in a symbiotic relationship and N fixation if used on chickpea.

Inoculants usually are available as a granulated product, applied similarly to an in-furrow fertilizer application, a liquid product, which is best applied to the seed and mixed and a powder, which requires a sticking agent and is mixed with the seed similar to what is required for the liquid products.

Seed-applied inoculant must be applied to the seed immediately prior to planting. Large populations of introduced rhizobia bacteria must survive in the harsh soil environment for two to three weeks to form nodules effectively on the roots of chickpea seedlings. In dryland cropping regions, peat-based granular inoculant is preferred because it is more reliable in dry seedbed conditions.

In acidic soils, use a granular inoculant instead of a liquid or powder formulation. In acidic conditions, the activity of the rhizobia is reduced, but the use of granular inoculant helps overcome this problem.

Inoculants are live bacteria, so they need to be handled and stored correctly. Avoid extreme heat or cold storing them in a cool, dark environment until needed is best. Seeding experts also recommend you do not pretreat seed and store it for more than one day.

Studies that have examined the value of inoculants to legume grain crops indicate that from 50% to 90% of the N used by chickpea during a season comes from N-fixation by the symbiotic N-fixing bacteria. Most studies that have examined N fertilization of chickpea found no value, and sometimes a yield reduction, from adding more than 10 pounds of N per acre to chickpea.

Avoid growing chickpea on soils with more than 60 pounds of N per acre residual N to the 2-foot depth because this resulted in lower yield than chickpea grown in soil with lower residual N.

Chickpea can achieve its yield potential on a wide range of soil pH from 5.3 to more than 7. Even at acid pH, yields might be maintained if a granular inoculant was used instead of a liquid or powder formulation. One problem with soil pH is the activity of the symbiotic bacteria, but the use of the granular inoculant solved that problem in a study that specifically looked at this issue.


Yield for a field in a given year is most dependent on the environment: rainfall, temperature and other factors. Within the environment, fertilizer rate is important. In a lower-yielding environment caused usually by too much water or not enough, nutrients are not as efficiently taken up, so rates relative to final yield are higher. In a high-yielding environment caused by close to ideal soil moisture and seasonal temperature, the efficiency of nutrient uptake is much higher, as is the release of nutrients from the soil and previous residues. The rates indicated in Table 9 are not related to yield goal but are appropriate for all yield environments.

A small amount of starter N increased early vegetative growth in one study and led to a slightly earlier maturity. You have little reason to apply more than 10 pounds of N per acre, usually contained in the P fertilizer source, to chickpea.

Phosphorus (P)

Desi-type chickpea have a lower demand for P, compared with the kabuli types. Kabuli chickpea growers often receive a premium for larger seed size, which is a consequence of greater P rates. Also, a small amount of P (about 10 pounds of P2O5 per acre) resulted in greater height of lowest pods due to increased early vegetative growth, which might be of benefit if the field has exposed rocks. Under all but the driest of soil environments, chickpea is relatively tolerant to up to 20 pounds of P2O5 per acre.

Potassium (K)

Chickpea has a similar low demand for K as field pea and lentil (Table 9).

Table 9. Phosphorus and potassium recommendations for desi- and kabuli-type chickpea.

Chickpea type Olsen P, pp, K soil test, ppm
0-3 4-7 8-11 12-15 16+ <100 >100
P2O5 rate to apply pounds per acre K2O rate to apply pounds per acre
Desi 40 30 20 10 0 30 0
Kabuli 60 40 30 20 10 30 0

Soil testing for soil sulfur is not diagnostic, so it should not be used in any consideration of S fertilization. In the past 20 years, our soils have become increasingly deficient in sulfur, except for our saline soil areas.

Although chickpea has the ability to support production of its own N nutrition through its relationship with N-fixing bacteria when inoculated, it has no means to support the production of S. Application of 10 pounds of S per acre as ammonium sulfate or another sulfate-containing fertilizer would supply enough S for a growing season, provided a heavy rain did not result in S leaching on sandy-textured soils.


No evidence indicates any micronutrient deficiency in chickpea in North Dakota.

Soluble Salts

Great variation in salt tolerance occurs among chickpea varieties. Generally, desi types are more tolerant to salts than the kabuli types. However, great variation occurs, even among varieties within type. More screening needs to be conductive to provide better grower guidance.

Determine soil salt (EC) levels, expressed as millimhos/centimeter, in areas that struggle to produce chickpea grain and plan to seed a more salt-tolerant crop there in the future. A comprehensive strategy to address salinity issues within fields helps expand future pulse crop options. For more information on addressing soil salinity, visit the NDSU Soil Health website (

Organic Production

Soil fertility is probably one of the minor management considerations for organic production of chickpea. Compost/composted manure would be a source of P, K and other nutrients for production of chickpea. The restriction would be to apply compost/manure the year prior to chickpea production so that too much N is not released during the early pulse growing season. Lacking access to compost/composted manure, buckwheat grown the year before and used as a green manure prior to seed set can make some P available to the chickpea.

Evidence also indicates that chickpea may have a similar ability to mobilize low-available Ca-held P, as does buckwheat. In a high-pH soil in India, an application of about 150 pounds per acre of finely ground rock phosphate resulted in a chickpea yield increase. Normally, rock phosphate does not release P in alkaline pH, but in this study, P was released under chickpea production.

Weed control and control of pests in general will be major considerations for organic chickpea production in North Dakota.


Multiple diseases, including root rots, can affect chickpea. However, Ascochyta blight is easily the most yield-limiting disease of the chickpea, and this disease section will focus exclusively on Ascochyta. We cannot overstate how important active and engaged management of Ascochyta blight on chickpea is to produce a successful crop. In a season favorable for disease development, total crop failure can result if Ascochyta blight is not managed appropriately.

Ascochyta Blight is Different

Ascochyta blight is a disease caused by the fungal pathogen Ascochyta rabiei. While the disease “Ascochyta blight” also occurs on field pea and lentil, Ascochyta rabiei is specific to chickpea. In other words, Ascochyta blight on chickpea is different from Ascochyta blight on lentil and field pea.

The pathogen is specific to chickpea and does not infect pea or lentil. It also is very aggressive on chickpea, and more importantly, the pathogen in chickpea has developed resistance to QoI fungicides (FRAC 11, also called strobilurins) in our region and is at risk of developing resistance to other classes of fungicides.

Identifying Ascochyta Blight

Scouting for Ascochyta blight is critical proactive and preventive disease management is necessary because Ascochyta blight cannot be controlled once it reaches epidemic levels. The pathogen can infect all above-ground plant parts any time after chickpea emergence.

Ascochyta blight first appears as small gray specs that quickly turn into brown lesions with dark borders. Small, circular black dots (fungal reproductive structures called pycnidia) will appear in lesions, frequently arranged in concentric rings resembling a bull’s-eye.

Ascochyta blight lesion on chickpea. (S. Markell, NDSU)

Ascochyta can affect all above-ground plant parts, including stems, leaves, pods and seeds. The disease often appears first in places close to areas where previous chickpea crops were grown or in areas of higher humidity and longer dew periods, such as along shelterbelts or in low areas.

Ascochyta blight lesion on chickpea stem. (S. Markell, NDSU)

Disease Cycle

The pathogen causing Ascochyta blight can survive for up to four years in infected residue and seed. If infected seed is planted, the pathogen can grow along with the plant. Even a very low level of infected seed can facilitate an epidemic in a favorable environment.

Ascospores produced on the infected residue (or seed) are dispersed aerially and can travel for miles. Spores that travel through air or from infected seed cause the first infections on leaves, stems or other above-ground tissue. Consequently, a field that never has been planted to chickpea, is not near other chickpea fields and is planted with clean seed still is not immune to Ascochyta blight and must be scouted.

Ascochyta blight develops most rapidly in cool (59 to 77 F) and wet conditions. The small black pycnidia that appear in lesions produce a second spore type (conidia) that are dispersed easily by rain splash and cause new infections within the field. If multiple infection cycles occur, an epidemic can decimate a chickpea crop quickly.

An epidemic can occur particularly fast in a season with frequent rains, heavy dews and high humidity. Hot and dry conditions will slow or stop disease development, but once favorable conditions return, the epidemic will resume.

Managing Ascochyta Blight

Ascochyta blight must be managed with as many strategies as possible. Reliance on fungicides or genetics alone is likely to result in management failure and large economic losses.

No single management strategy can guarantee disease prevention, so use all available strategies to prevent or delay infection. Here are some strategies:

  • Plant clean seed. This is critical to ensure that high amounts of the pathogen will not be brought into the field at planting. Use seed treatments that are efficacious on Ascochyta.
  • Practice long crop rotations to help limit the inoculum already present in the field. This is particularly important in minimum and no-till systems.
  • Select resistant chickpea varieties. While selecting a variety completely resistant to Ascochyta blight is not possible, some varieties are less susceptible than others.

Fungicides also can be an effective tool to manage Ascochyta blight, but field scouting, application timing, fungicide selection and fungicide rotation are critical for success. See NDSU Extension publication PP622, “North Dakota Field Crop Plant Disease Management Guide,” for more information. Multiple fungicide applications likely will be needed to manage the disease in a growing season.

At the time of this printing, QoI fungicides (FRAC 11: also called strobilurns) are not effective on Ascochyta blight in North Dakota because the pathogen population has developed resistance to them. This includes products such as Headline and Quadris, which are compounds in many premixed products.

However, at the time of this printing, DMI fungicides (FRAC 3: also called triazoles) and SDHI fungicides (FRAC 7) can be used to manage the disease, but the pathogen population could develop resistance to them in the future. Other chemicals, such as chlorothalonil (FRAC M5), are less efficacious but can be useful in fungicide rotation strategies and are unlikely to be rendered ineffective by pathogen resistance development.

When preparing to manage Ascochyta blight with fungicides, consult the most up-to-date information on fungicide timing, efficacy and rotation strategy.

Weed Management

Chickpea is a poor competitor with weeds at all stages of growth. Slow seedling growth, in addition to a relatively sparse optimum plant population of three to four plants per square foot, results in an open crop canopy, which requires season-long weed management. Crop rotation and field selection are cultural methods that should be used as part of an integrated weed management program.

Cultural weed control begins with avoidance. Avoid fields where perennial and annual broadleaf weeds are a major problem, and be sure to control these weeds in the preceding crop. Kochia, Russian thistle, wild mustard and wild buckwheat are the most problematic annual weeds in chickpea and can cause major problems for direct harvesting.

Weeds can be managed with stale seedbed techniques, provided the grower is willing to risk yield loss due to delayed seeding. Stale seedbed techniques include delaying seeding and allowing weeds to emerge, then controlling them with tillage or a nonselective herbicide.

Generally, the first flush is the largest, and the earliest emerging weeds are the most competitive. Stale seedbed techniques are not foolproof because weeds will continue to emerge throughout the growing season, and warm-season annual weeds such as green foxtail (pigeon grass) may be favored by delayed seeding.

As of 2019, no herbicides are registered to be applied postemergence to control broadleaf weeds in chickpea. Group 1 herbicides can be used to control grass weeds. Controlling emerged weeds with a good burn-down before planting chickpea and using pre-emergent (PRE) herbicides to extend control as long as possible into the growing season are important.

Chickpea is a small, short plant, slow to canopy, and the canopy may not fully close. Without good weed control, yield loss can be substantial.

Several soil-applied herbicides are labeled for managing weeds in chickpea (Table 10). Troublesome broadleaf weeds such as kochia and Russian thistle can be controlled in no-till chickpea with sulfentrazone (Spartan Charge, Spartan Elite and BroadAxe XC) applied in the fall before chickpea is planted or as an early preplant application. NDSU research has shown that spring-applied sulfentrazone provided better season-long control, compared with fall applied.

NDSU research has shown that higher rates of sulfentrazone may be required to control wild buckwheat. Sulfentrazone can be applied from up to 30 days prior to planting to three days after planting.

A burn-down herbicide such as glyphosate may be tank mixed with sulfentrazone if emerged weeds are present. For optimum activity, sulfentrazone needs 0.5 inch of moisture soon after application to become activated in the soil.

Soil factors such as pH, texture and organic matter content affect sulfentrazone activity in soils. Growers should consult the label or a product representative carefully to determine optimum Spartan rates for their fields.

Flumioxazin (Valor) can be applied in the fall prior to planting chickpea. Flumioxazin has shown good residual control of several winter annual weeds as well as volunteer canola. Pendimethalin (Prowl) also can be applied fall or spring for broadleaf and grass control, but best results typically are achieved with the fall application.

In conventional tillage systems, trifluralin (Treflan), ethalfluralin (Sonalan) and pendimethalin (Prowl) incorporated preplant will control certain broadleaf weeds, plus foxtail and barnyard grass, but not wild oat or quackgrass. Imazethapyr (Pursuit) can be incorporated preplant or pre-emergence to control certain broadleaf and grass weeds. However, imazethapyr will not control ALS-resistant kochia, and the user assumes all risk of crop injury.

Several soil-applied herbicides are labeled for managing weeds in chickpea (Table 10). Troublesome broadleaf weeds such as kochia and Russian thistle can be controlled in no-till chickpea with sulfentrazone (Spartan Charge, Spartan Elite and BroadAxe XC) applied in the fall before chickpea is planted or as an early preplant application. NDSU research has shown that spring-applied sulfentrazone provided better season-long control, compared with fall applied.

NDSU research has shown that higher rates of sulfentrazone may be required to control wild buckwheat. Sulfentrazone can be applied from up to 30 days prior to planting to three days after planting.

A burn-down herbicide such as glyphosate may be tank mixed with sulfentrazone if emerged weeds are present. For optimum activity, sulfentrazone needs 0.5 inch of moisture soon after application to become activated in the soil.

Soil factors such as pH, texture and organic matter content affect sulfentrazone activity in soils. Growers should consult the label or a product representative carefully to determine optimum Spartan rates for their fields.

Flumioxazin (Valor) can be applied in the fall prior to planting chickpea. Flumioxazin has shown good residual control of several winter annual weeds as well as volunteer canola. Pendimethalin (Prowl) also can be applied fall or spring for broadleaf and grass control, but best results typically are achieved with the fall application.

In conventional tillage systems, trifluralin (Treflan), ethalfluralin (Sonalan) and pendimethalin (Prowl) incorporated preplant will control certain broadleaf weeds, plus foxtail and barnyard grass, but not wild oat or quackgrass. Imazethapyr (Pursuit) can be incorporated preplant or pre-emergence to control certain broadleaf and grass weeds. However, imazethapyr will not control ALS-resistant kochia, and the user assumes all risk of crop injury.

Table 10. Chickpea herbicides for North Dakota.

Grass and some broadleaf weeds

Poor wild oat and no wild mustard control

1.5 to 2 pt. EC
5.5 to 7.5 lb. 10G (0.55 to 0.75 lb.)

Insect Pests

The NDSU Extension publication E1877, “Pulse Crop Insect Diagnostic Series: Field Pea, Lentil and Chickpea,” summarizes integrated pest management for insect pests of pulse crops, including identification, crop damage, monitoring or scouting tips, economic threshold, cultural control, host plant resistance, biological control and chemical control.

Chickpea stems, leaves and seedpods are covered with small hairlike glandular structures that secret malic and oxalic acids, which deter insect pests. Researchers have observed that some grasshopper species are reluctant to feed on chickpea.

Researchers also have noted that chickpea fields infested with mustard will suffer some cabbage looper feeding injury on chickpea plants adjacent to mustard plants. Cutworms and wireworms occasionally damage chickpea stands as well.

For information about insects in chickpea, see the pea insect section.

Insecticides registered for insect pest management in chickpea are listed in the current issue of the NDSU Extension publication E1143, “North Dakota Field Crop Insect Management Guide.” Pesticide applicators must read, understand and follower all label directions.


Factors That Affect Ripening

Chickpea has an indeterminate growth habit, which means the growth cycle extends as long as moisture is available. This growth pattern can be problematic in fields with uneven topography, where soil water varies throughout the field, or where seeding problems caused uneven emergence.

Herbicide injury, disease and predation by deer also commonly affect maturity and can result in uneven field ripening, sometimes causing green pods to persist until the first fall frost.

Green pods that are frozen or desiccated will remain green and become an important downgrading factor. Less than 1% of green seeds are allowed for the top U.S. commercial grade. Growers should cut around portions of the field with high green seed counts to avoid ruining the whole lot. To maintain a timely harvest for seed quality, some producers have combined different parts of the same kabuli chickpea field on three different dates.

Plants are physiologically mature when seeds begin to change color inside the uppermost pods. Producers have the option to direct combine or swath the crop when the pods are straw yellow.

Most chickpea is sold as a high-quality human food product. While seed size is a major factor in economic returns for the kabuli type, seed color is the single most important factor in determining marketability of the crop. If the seed coats are dark or discolored, the crop will not be accepted by food processors.

Harvesting decisions such as timing and harvesting methods are the major factors determining if you will harvest seeds with the light yellow to cream color demanded by processors. Delayed harvest can result in weathered seed that is not marketable.

Chickpea seed has a thin seed coat that is very susceptible to cracking, which can reduce germination. Combine cylinder speeds should be as low as possible to avoid cracking the seed coat.

Harvest Methods

Chickpea normally has low shattering potential, although pod drop has occurred in some instances when harvesting was delayed. Pod shattering can occur with unusually hot late August and early September temperatures.

The lowest pods typically are 4 inches off the ground, making direct harvesting possible but requiring an experienced combine operator. In some regions, swathing and combining are advantageous due to the fact that delayed harvests can result in darkening of the seed coat.

Most growers desiccate chickpea prior to harvest to facilitate even dry-down. Many varieties are indeterminate and will keep growing as long as they can. In some cases, mature seed is at risk of shattering at the bottom of the plant, while green plant tissue with immature pods persists at the top. Therefore, the decision about when to desiccate needs to balance harvestable yield and quality with the risk of shattering.

Several chemical desiccants are labeled for chickpea in North Dakota (Table 11). If producers prefer desiccation to swathing, they should be aware that a crop intended for seed should not be desiccated with Glyphosate or Sharpen because germination can be affected negatively.

Monitoring seed color is very important to determine proper harvest timing and management. Chickpea can be harvested at 18% moisture but requires that the crop ripen uniformly, which is rare.

Table 11. Preharvest herbicides for chickpea in North Dakota.

1.2 to 2 pt. 2SL
0.8 to 1.3 pt. 3SL
(0.3 to 0.5 lb.)

Prior to harvest greater than 80% yellow/brown pods and less than 40% green chickpea leaves

Paraquat = 7 days.
Sharpen = 2 days.

Minimizing Seed Damage

Combine speeds, cylinders, sieves and air must be adjusted to prevent seed breakage. Chickpea seeds have a characteristic, protruding beaklike structure that must not be damaged. Seed damage can be minimized by the use of conveyor belts or by keeping augers as full as possible and operating at slower speeds.

Chickpea can be stored at 15% moisture. Minimizing the number of times chickpea is handled reduces the number of cracked or damaged seeds, which are significant dockage factors.

How much Nitrogen?

The main thrust of our disagreement was over the issue of the source of nitrogen for growing crops that are going to feed the world. Tom quoted Norman Borlaug as saying that organic would not be able to feed the world, and tried to address it with the ISU brochure. But as I pointed out, Tom cut off the quote, avoiding a key phrase that indicates he is talking about nitrogen production. Here is the full quote:

That’s ridiculous. This shouldn’t even be a debate. Even if you could use all the organic material that you have–the animal manures, the human waste, the plant residues–and get them back on the soil, you couldn’t feed more than 4 billion people. In addition, if all agriculture were organic, you would have to increase cropland area dramatically, spreading out into marginal areas and cutting down millions of acres of forests. At the present time, approximately 80 million tons of nitrogen nutrients are utilized each year. If you tried to produce this nitrogen organically, you would require an additional 5 or 6 billion head of cattle to supply the manure. How much wild land would you have to sacrifice just to produce the forage for these cows? There’s a lot of nonsense going on here.

This key phrase underscores the perennial problem of switching from fertilizers to an organic-only approach. The first question is where you are going to get the nitrogen that plants need to grow? It takes a lot of energy to pull nitrogen out of the air and break its triple-bonds to turn it into a form that plants can use. This is a major energy cost for conventional farming, but it also secures its higher yield. The only way that organic agriculture can get nitrogen is by harvesting it from other living things in one way or another. Nitrogen can be “fixed” from the atmosphere by legumes, which can be grown as a “cover crop” that is planted after the fall harvest, or in the spring to cover the land in an off-year and gather nitrogen that will be plowed into the soil. You can also plant a “catch” cover crop with a grain such as barley or oats, intended to capture excess nitrogen during the winter, which can be plowed into the soil in he spring. Or, you can gather nitrogen in the form of animal manure – which comes from previously-grown crops, and thus, previous sources of nitrogen. You could also go for fish slurry – and harvest your nitrogen from the ocean, or weirder still, argue over naturally-occurring deposits of Chilean nitrate (PDF) and their status in organic agriculture. In any case, the nitrogen has to come from somewhere. Ironically it would seem, nitrogen from human waste is not allowed. The ISU research that Tom was enthusiastic about was a little fuzzy on where the nitrogen was coming from:

The organic plots receive local compost made from a mixture of corn stover and manure.

Nitrogen Cycle, from
Where did this manure come from? How many acres of land were required to produce this manure, and where did the nitrogen come from to produce it? These are questions that are not detailed, and it shows one layer to the complexity of long-term sustainability. Tom responded to defend organic agriculture with a paper that estimated that with cover crops alone (PDF), the world could produce enough nitrogen to replace all synthetic fertilizers. The Badgley et al. paper had many assumptions, but also some good information. Their basic approach was to estimate how much available nitrogen can be produced on all the non-forage croplands in the world. Essentially, how much can we gain by planting legume cover crops? But this is where the incompleteness of the paper began to unravel.
The paper assumed that none of the croplands currently in production were being planted with cover crops already. So the acreage of non-cover-cropped lands was overestimated. Next, it also assumed that legume cover crops would actually grow on all of these acres. Statistics about current practices are very hard to find, and the one that I could find (PDF), for New York vegetable growers (not grain), said that 50% of their acres had cover crops, and 20% of those were legumes fixing nitrogen. As I have learned, besides the timing of planting and the weather, certain cover crops can make pest problems worse, and if you follow a legume crop with a legume cover crop, you can have issues with rotting. Before you can estimate whether cover crops can provide enough nitrogen to replace fertilizers, you first have to estimate what can be practically achieved in actual cropping systems. Even the Rodale research did not plant legume cover crops every year.
I then had a thought. If you are going to plant a legume cover crop (as with any cover crop), you are going to need seeds. Those seeds have to come from somewhere, and will take up a certain amount of acreage to produce. Out of curiosity, I thought I would calculate how many acres of farmland would be required to grow the seeds necessary to cover the world’s croplands in hairy vetch, a common and highly regarded legume cover crop. The results were stark.
The Badgley paper estimated the total available croplands as 1362 M hectares (Table 4), and if all were planted with legume cover crops, it would produce 140 Million Megagrams of Nitrogen (or 140 Teragrams). The paper reports that the world uses 82 M Mg of Nitrogen (82 Tg), which means that according to these numbers, to exactly replace the amount of nitrogen being used by farms today, you would need 1362 * 82 / 140 = 798 M hectares of legume cover crops – so about 800 million hectares. How much seed would you need to plant that?
Hairy Vetch. Photo by neckonomania
The recommended seeding rates for hairy vetch are 30 pounds per acre. The only source I was able to find about seed production of hairy vetch reported that you can only get 200-540 pounds per acre of seed (PDF). This means that for every acre of cover crop, you would need 1/6 to 1/18 of an acre to produce the seed you would need. (You also need to produce the seed for the seed crop – making it slightly higher). Without knowing the true average for seed production, I just averaged the high and low-end of the range to arrive at 1/12 of an acre of seed fields to produce enough hairy vetch for one acre of cover crop. To plant 800 million hectares of hairy vetch cover crops, we need about 67 million hectares (or 164 M acres) of hairy vetch seed production to supply it. For seeds to plant the seed fields, add another 6 million hectares to give you 73 million hectares of land.
For perspective, I looked up the total cropland of my awesomely-productive home state of California, which according to the USDA, has 4 million hectares under cultivation. This means that we would need almost 20 California’s of cropland to grow enough hairy vetch seed to plant these 800 million acres, and if you converted all Californian farmland into seed production (goodbye meat, dairy, etc) you still only have 10 M hectares, and you would need the farmland of 7 Californias.
Where are we going to find this extra land? Or should we decrease the total cropland area in the world by five and a half percent? (73 / 1362 = 5.4%) This is the opposite of feeding the world, and it presents a real challenge for cover crops. But not the last challenge, either.
Another detail worth noting is that the yields of these organic plots can have higher total nitrogen applied when compared to conventional plots. In this paper (PDF) on nitrogen rates and leaching, also from Rodale, almost twice as much nitrogen was applied every year in the organic plots relative to conventional, in order to maintain their yields (Table 4). This translates, as admitted in the paper, into greater rates of nitrogen leaching into the surrounding environment. Nitrogen in the soil is a very mobile nutrient – it washes out easily. Nitrogen runoff from farmlands contributes to water pollution, leading to things such as the Dead Zone in the Gulf of Mexico. It turns out that according to more Rodale research (PDF), not only do organic farms leach just as much nitrogen as conventional farms, but farms with legume cover crops leach even more. 20% of the applied nitrogen leaches out of organic manure and conventional systems, while 32% of the nitrogen applied to legume cover-crop systems leaches out. There is a lot of research on nitrogen leaching and cover crops, including some that don’t sound so bad for leaching, but there is a shortage of good long-term leaching studies. There is also evidence that the cover crop can harm the yield of the following crop. Not only does the amount of nitrogen applied to maintain yields call into question the sustainability of these sources of nitrogen, but also the environmental sustainability of the downstream effects of legume cover crops as a silver-bullet solution to the world’s nitrogen needs.
So even post-mortem, Norm still beats Tom in an argument. Cover crops in an organic system have a long way to go to get to “feeding the world.” This is not to say there isn’t potential in cover crops – because there is. But one thing we must not slip into is silver-bullet thinking – nor excluding a tool from a toolbox because someone calls it a silver bullet.


The liter­a­ture sug­gests there is about a 1 % risk per year of a 10 % global agri­cul­tural short­fall due to catas­tro­phes such as a large vol­canic erup­tion, a medium as­ter­oid or comet im­pact, re­gional nu­clear war, abrupt cli­mate change, and ex­treme weather caus­ing mul­ti­ple bread­bas­ket failures. This short­fall has an ex­pected mor­tal­ity of about 500 mil­lion peo­ple. To pre­vent such mass star­va­tion, al­ter­nate foods can be de­ployed that uti­lize stored bio­mass. This study de­vel­oped a model with liter­a­ture val­ues for vari­ables and, where no val­ues ex­isted, used large er­ror bounds to rec­og­nize un­cer­tainty. Then Monte Carlo anal­y­sis was performed on three in­ter­ven­tions: plan­ning, re­search, and de­vel­op­ment. The re­sults show that even the up­per bound of USD 400 per life saved by these in­ter­ven­tions is far lower than what is typ­i­cally paid to save a life in a less-de­vel­oped coun­try. Fur­ther­more, ev­ery day of de­lay on the im­ple­men­ta­tion of these in­ter­ven­tions costs 100–40,000 ex­pected lives (num­ber of lives saved mul­ti­plied by the prob­a­bil­ity that al­ter­nate foods would be re­quired). Th­ese in­ter­ven­tions plus train­ing would save 1–300 mil­lion ex­pected lives. In gen­eral, these solu­tions would re­duce the pos­si­bil­ity of civ­i­liza­tion col­lapse, could as­sist in pro­vid­ing food out­side of catas­trophic situ­a­tions, and would re­sult in billions of dol­lars per year of re­turn.

Friday, October 4, 2013

New Car!

Although this post is a bit late to the punch, as of the beginning of August I now have a car instead of the moped I've been using to get around town.

It's a Honda Civic LX, 2013 model, silver in color, and I love it. I've gotten progressively more and more tired of riding around Hilo in the rain, and have been thinking it'd be nice to be able to explore some more around the island.

To be clear, I haven't actually bought it, I'm just leasing it through the beginning of 2015 (which works out well since I expect to be attending graduate school somewhere else by the time 2015 rolls around).

It's got all kinds of nice features, like keeping me dry as I'm going about town. And air conditioning! And I can directly attach my phone with all my music on it to the sound system via auxiliary cable. very nice. Oh, and great gas mileage – I get about 27 miles to the gallon, which is pretty good considering nearly all of my driving is in the extremely hilly city of Hilo.

For those of you curious what it looks like, have some pictures:

Waiting on amber: a note on regenerative agriculture and carbon farming

This post offers some further notes on the issue of carbon farming and regenerative agriculture, arising out of the discussion in this recent post of mine, particularly via the comments of Don Stewart. Don set me some onerous homework – a lengthy presentation by Elizabeth and Paul Kaiser of Singing Frogs farm in California, another lengthy presentation by David Johnson of New Mexico State University, and an interview with Australian soil scientist Christine Jones. Diligent student that I am, not only have I now completed these tasks but I’ve also read various other scientific papers and online resources bearing on the issue and am duly turning in my assignment. I hope it’ll provide some interest and a few points for discussion.

I started out with considerable sympathy towards carbon farming and regenerative agriculture, but with a degree of scepticism about some of the loftier claims made on its behalf by regenerative agriculture proponents (henceforth RAPs). And in fact that’s pretty much where I’ve ended up too, but with a somewhat clearer sense of where my grounds for scepticism lie. I hope we’ll see a shift towards more regenerative agriculture in the future. But if that’s going to happen, the RAPs will have to persuade a lot of people more inclined to scepticism than me about the virtues of their proposals – and if they’re going to do that, I think they’ll need to tighten up their arguments considerably. Anyway, in what follows I define what I understand regen-ag to be and then critically examine some of the claims about it.

Defining regenerative agriculture and carbon farming

Doubtless there are numerous possible emphases, but the fundamental idea revolves around restoring or maintaining the biological life of the soil, in particular the fungal component. Working as symbionts to plants and other soil organisms, fungi are able to deliver nutrients to plants that are otherwise unavailable, and also to sequester carbon by absorbing carbon dioxide from the air and turning it into stable organic carbon compounds in the soil. In order to achieve this, it’s essential to avoid tillage, since this destroys the fungal hyphae in the soil, and to keep the soil covered with living plants at all times so that there’s a healthy rhizosphere (root zone) interacting with the soil food web. It can also be necessary to inoculate the soil with the right kinds of fungi – apparently, not just any fungi will do 1 .

So the three key characteristics of this kind of agriculture are zero tillage, continuous cover cropping and fungal inoculation. David Johnson states that a one-off ‘dusting’ of 400-500lbs of inoculant per acre (that’s 450-560kg per hectare for those of us still hanging on in there in Project Europe) is all that’s necessary to create the right initial conditions in the soil for many years to come.

Proponents of this kind of regenerative agriculture have variously claimed that it can:

  • Protect soil from erosion and depletion, and indeed actively build soil
  • Provide adequate crop nutrients with minimal external inputs
  • Produce high yields
  • Produce healthy crops that are weed and pest-free
  • Sequester human greenhouse gas emissions – possibly all of them
  • Earn greater financial returns for farmers
  • Improve human health

If all that turns out to be true, then this is fantastic news. But these are powerful claims, and it’s surely reasonable for them to be examined closely before we collectively hitch our wagon to regen-ag. So here, in each case I try to highlight things that seem to be more or less well established beyond reasonable doubt, and things that don’t seem so well established, at least to me. I’m not an agronomist or a soil scientist, so doubtless there are things that aren’t obvious to me which are obvious to others, though I have a sneaking feeling that a few of the non-obvious things are brushed aside a little too quickly in the Regen-Ag movement, perhaps because they don’t quite fit the narrative. And then there are one or two things I’d like to highlight that seem not well established at all. So we have green-amber-red: Small Farm Future’s traffic light guide to Regen-Ag.

I think it’s reasonably well established that no till, continuous cover-cropping protects soil from physical erosion better than tillage farming 2 , so we can start with a green light. It’s not an all or nothing thing, however. There are places with strongly erosive conditions where it’s a really, really bad idea to practice tillage agriculture from a soil protection point of view, and others with less erosive conditions where perhaps it’s only a slightly bad idea. Sensitivity to local context, and other pressures, is in order before deciding how much to censure tillage practices. Nevertheless, I think it can be agreed that tillage is best avoided whenever possible. Of course, the mainstream ‘no till’ approach involves using copious quantities of glyphosate, synthetic fertiliser and heavy, compacting machinery of the kind that the late, lamented Gene Logsdon subjected to gentle ridicule in various articles 3 . It’s tempting to say that’s a whole different ball game from Regen-Ag, but actually it isn’t entirely. Many farmers lauded for their Regen-Ag credentials like Gabe Brown and Gail Fuller routinely use glyphosate or other herbicides, even if at a lesser rate than conventional farmers 4 . I’m not inclined to criticise them for it, but it falls some way short of the desiderata for a healthy soil food web generally emphasised by the RAPs, without apparently receiving much discussion.

In terms of actually building soil, RAPs like Christine Jones and Elaine Ingham commonly critique the widespread notion that soil formation is a slow process, arguing that topsoil formation can be ‘breathtakingly rapid’ 5 . But it’s rarely stated how rapid. Many no till, regen systems I’ve seen involve importing compost in bulk. But that’s not soil building – it’s soil importing. So my question is, allowing for an initial ‘dusting’ of inoculate à la David Johnson, how quickly do soils under a regen-ag regimen typically ‘build’ with no subsequent imports or amendments, with crops being removed from them for human consumption all the while? Until that question is satisfactorily answered, I think the ‘building’ claim stays on amber.

The Kaiser’s Singing Frogs farm seems to involve importing quite a lot of compost, even if it’s used only as a soil amendment that helps stimulate the soil food web. In addition to the compost applied to their growing beds, they raise most of their plants initially as transplants in the greenhouse, which presumably also involves importing a lot of substrate. This is how most small market gardens operate, including mine (we import woodchip and some substrate). In our present economy, flush with fertility and fossil fuels, it’s a rational thing to do. But you do have to pay close attention to where the compost or substrate comes from, and how feasible it would be to scale its supply up across the farm sector as a whole, before concluding that soil-building of this sort has global replicability. Historically, in low energy situations the choice was essentially between tillage farming or diligent and extremely labour-intensive cycling of nutrients locally. As we confront the possibility of a lower energy future, it seems unlikely that farming systems based on importing compost in bulk will figure heavily.

There seem to be two ideas here. First, that once the soil food web is in good heart, there are enough nitrogen-fixing bacteria in the soil to give the crops all the nitrogen they need in better forms than synthetic fertiliser, which ultimately has a destructive effect on the soil food web and on the ability of plants to take up nutrients 5 . And second, that the overall metabolism of the soil food web makes the other nutrients needed by the crop more available than in soils compromised by conventional practices.

The first point seems plausible to me, but not definitively established. I think more quantitative evidence is required, which I didn’t find in my various readings of the RAPs. Much as I share the dislike of the RAPs for synthetic fertiliser (and I’ve never used it myself), about 40% of the current global food supply is based on the application of synthetic nitrogen compounds – this was a major limiting factor in 19 th and early 20 th century agriculture, and it seems doubtful that human populations would have reached their current level without the invention of the Haber-Bosch process 6 . Undoubtedly, there are downsides to synthetic fertiliser. The RAPs may be right that ultimately it’s destructive of soil health. And we may be able to do without it – either by careful cycling of organic nutrients, or by the kind of soil food web route advocated by the RAPs. Various people – including me – have asked whether it’s possible to feed the world through organic farming alone, and answered with a tentative yes. It certainly makes sense to start weaning ourselves off synthetic fertiliser whenever we can, but from a global food security viewpoint our current tentative yeses don’t seem quite enough for us to blithely ditch the synthetics quite yet. Generalised or anecdotal claims that crops will do better without synthetic fertiliser are all very well, but I think such claims have to stay on amber until more quantitative data is forthcoming.

In relation to other nutrients, I get that a thriving soil biota can pull in carbon, nitrogen and oxygen from the atmosphere, but all the other nutrients have to come from the soil. David Johnson talks about the “increase in the availability” of such nutrients in his version of Regen-Ag, which he calls “Biologically enhanced agricultural management” (BEAM) 7 . It’s plausible to me that a healthy soil biota makes these nutrients more available to crops than they’d otherwise be, but (unlike C, N and O) it can’t conjure them out of thin air. So if crops are being taken off, then it seems to me that ultimately these nutrients are being mined from the soil, unless they’re somehow getting put back too 8 . But since Dr Johnson also enthuses about retaining his modern lifestyle and jetting off to distant conferences, it doesn’t seem that he’s thinking of a smallholder-style world of careful nutrient cycling. So I wonder where these nutrients are coming from. Maybe the RAPs would argue that there are effectively limitless quantities of them in the soil if only they can be made more available by the soil biota – I’ve heard Elaine Ingham imply as much 9 . But again, I’d like to see more quantification of this point. By my calculations, for example, the 65 million of us in the UK need to consume about 24,000 tonnes of phosphorus annually, which would minimally involve stripping the phosphorus in its entirety out of about 24 million tonnes of soil every year, and that at an improbable 100% extraction rate. So for the moment I consider this another amber, at best.

Yet again, I’m struggling to find much quantification here. In Christine Jones’s article, various farmers practising regen-ag are mentioned who are “getting fantastic yields” 10 . Well, how fantastic? Wheat yields in the USA, for example, have averaged 46.7 bushels per acre nationally over the last five years 11 . How do the wheat yields of regen-ag farmers compare? I’m not seeing too many hard and fast figures in the literature.

Let me unpack this point a little under these four heads:

  • Biomass and harvest index
  • Necessary yield
  • Competition and agronomic variation
  • Cropland-grassland balance

Biomass and harvest index: David Johnson presents figures for the most productive natural ecosystems which suggest they produce up to four times more biomass than agroecosystems despite all the fertilisation and irrigation lavished on the latter. From this he infers that “We’re doing something wrong” 12 . But the main purpose of agroecosystems isn’t to maximise the production of biomass, it’s to produce digestible human food – carbohydrates, proteins etc. Human crop breeding efforts have actively tried to reduce the amount of inedible biomass relative to the edible portion of the crop (ie. increase the harvest index). In this sense, Johnson’s comparison presents little useful information. Further, the high productivity natural ecosystems he identifies are all from hot and/or humid places (swamps, rainforests…even kelp beds). It’s not clear that the same is true of his agroecosystem figure, so I’m not sure he’s comparing like with like. Then Johnson presents data showing that his BEAM system produces way more biomass than even the natural ecosystems. He doesn’t always make it clear exactly what these high biomass BEAM plants are, but they generally seem to be cover crops which, by definition, are plants that are unusually good at quickly producing copious leafy biomass in the short-term. So it’s not necessarily surprising that they outperform the range of plants found in natural ecosystems and agroecosystems. High biomass production can be one important agricultural goal, but what’s ultimately of greatest interest is the yield of the edible portion of the crop. The table that Johnson really needs to present here is the yield of edible biomass or of metabolisable human nutrients in the various different regimens. It’s impossible to know if we’re ‘doing something wrong’ in crop yield terms until he does.

Necessary yield. Of course, yield isn’t everything. A lot of crops are fed inefficiently to livestock, or exported, or end up as food waste. Undoubtedly there’s some slack in the system, so it doesn’t necessarily matter if regen-ag yields are lower than conventionally-grown crops if they bring other benefits. As with enthusiasts for perennial grain crops, the RAPs seem to feel the need to claim that crop yields are as good or better than conventional crops, when this may not be necessary for their case, and potentially draws us into needlessly oppositional arguments. But ultimately it’s necessary for any agricultural system to yield enough to feed the people relying on it. What counts as enough isn’t an exactly quantifiable number, but it should be roughly quantifiable, and I’d like to see the RAPs roughly quantify it.

Competition and agronomic variation: at one point in his presentation, David Johnson likens our major crop plants to weeds and says “we’re good at growing weeds”. That’s exactly right. The basic characteristic of most of our major crop plants is that, like most weeds, they’re pioneer, short-lived (usually annual or biennial, sometimes short-lived perennial) plants that usually fare best in disturbed (ie. ploughed), highly fertile ground. As argued above, disturbed ground isn’t ideal for other reasons, so if we’re going to grow our standard crops in regen-ag systems, then essentially we’re going to have to ‘trick’ them into growing in circumstances they don’t particularly favour. In particular, we’re probably going to have to grow them through cover crops that may compete with them for water, light and some nutrients, even if they may donate other nutrients (like nitrogen). Therefore we might expect them to yield less. Generally, the way farmers bicrop cash crops with cover crops if they don’t use herbicide (which in fact most of them do) is to use some kind of inherent seasonal check to the latter (eg. flooding, extreme heat/drought, or extreme cold) or else by damaging them mechanically by some method that falls short of full tillage. But that’s not possible everywhere – for example, in the moist temperate zone where I live, cover crops can happily grow more or less year round and I’m not sure there are obvious ways that, for example, a cereal crop could be established directly into them with uniform success and good yields. This article about Kansas regen-ag farmer Gail Fuller says “Instead of trying to figure out the best way to terminate a cover crop or pasture, Fuller is looking for ways to knock it back for a few days to allow the cash crop to compete as a companion crop”. Where I live, I don’t think ‘knocking back’ a cover crop for a few days would be anything like enough to establish a successful cereal crop into it – which is why cover-cropping farmers here continue to use glyphosate routinely. My feeling is that further experimentation with cover cropping may eventually mitigate this problem, probably at the cost of some yield loss. But it doesn’t seem to me that humanity has really cracked this one yet. I think the RAPs need to discuss this issue more clearly, perhaps with an acknowledgment that – as with their ideal cover crop – it’s not yet cut and dried.

Cropland-grassland balance: many of these cash crop-cover crop trade-offs disappear when the focus shifts to farming ruminants on grass, because – notwithstanding many farmers’ taste for temporary perennial ryegrass – the cash crop in this instance is essentially a long-term cover crop, which therefore fits easily into the logic of regen-ag. Perhaps it’s no coincidence that the farmers who get star billing as regen-ag pioneers are often ranchers on extensive, semi-arid grassland who are restoring soil and vegetation in the aftermath of ill-advised intensive grazing or tillage. All credit to them, but in terms of global food production it would be stretching a point even to call this a sideshow. The problem with grass as a crop is that humans have to jump a trophic level in order to be able to consume it as beef, lamb etc. and – as the likes of George Monbiot tirelessly, and correctly, remind us – this is pretty inefficient energetically. The contribution of rangeland beef to global food intake is minimal. On this note, Gabe Brown is frequently cited as a regen-ag pioneer. I haven’t yet established exactly what Brown’s system is and what his yields are, though it seems he has long fallows in his grazing rotations. Makes sense…but then he has a lot of (presumably cheap) acres to play with. Maybe his yields stand up even so. If so, it hardly fits into a Boserup model of agricultural intensification. Gail Fuller says “with low grain prices my bottom line is better grazing cover crops and pastures than growing corn…Right now, I make more money grazing” 13 . Of course, that’s absolutely fine at the individual farm level (though maybe it raises a question mark or two about those ‘fantastic’ regen-ag yields). But at the global food system level, it probably wouldn’t be fine, and we need to address that too.

In summary, I’m open to the idea that regen-ag methods produce ‘fantastic’ yields, but I’d like to know what they are. If no-till, cover-cropping methods can match or surpass tillage plus added-fertility methods for crop yield (rather than biomass yield) then that indeed would be fantastic – but it would run counter to what we’ve learned historically about agricultural development. Even if they can’t match them, it may not matter if they can yield enough. But some good, global quantification is necessary. For the moment, there are many ambers here.

It seems plausible that a healthy soil biota, with fungal networks optimising nutrient transfer, will produce healthy crops – perhaps healthier than ones propped up by an agri-chem plus tillage approach. At the same time, as mentioned above, most of our crops are based on weedy, pioneer species that like to hoover up nutrients in disturbed soil, and they’ve been further bred to amplify these characteristics. So the idea that they’re happier in undisturbed fungal soils arguably requires demonstrating, rather than being assumed. I’d judge this assertion to be hovering on amber.

No doubt it’s true that healthy plants are more resistant to weeds and pests. This has long been the refrain of the organic movement, and I think it’s defensible so long as you don’t overplay the argument. Our crops, remember, are basically weeds, and the kind of soils they like to grow in will generally be to the liking of other weeds that humans don’t want. At Singing Frogs Farm, the Kaisers emphasise the use of mature transplants as a strategy to prevent weed ingress. That makes sense in the context of a small market garden, but it speaks of weed management, not a weed-free agronomy. It’s also labour and compost-intensive. It’s not necessarily applicable to broadscale farming – unless the argument is that we should minimise the latter and emphasise small-scale, labour-intensive farming. That, I think, is precisely what we should be doing. But we won’t have banished weeds, and we’ll have to scratch our heads to find the necessary inputs.

The pest issue mirrors the weed one. Different kinds of pests adapt to different kind of cropping regimens in different ways, and again it’s a matter of management rather than banishment. The Kaisers discuss the bird and insect problems they have and the crop covers they use to minimise these – so clearly they have pest problems. I find implausible the notion of a farm so tuned in to the natural world that none of its crop ends up in the stomachs of wild critters. Indeed, a farm tuned in to the natural world probably ought to be one in which some of its crop does end up in the stomachs of wild critters.

For me, it’s a red light on this claim.

It’s generally agreed that soils can act as a sink for carbon, and that soils containing a healthy food web are better at sequestering it – for example, through the fungal creation of chitin which holds it in a relatively immobile form. So I think we can probably award a green light to the basic claim that regenerative agriculture can sequester carbon. I say ‘probably’ because there are studies that contest the idea of carbon sequestration through no-till regimens 14 – it seems to be the case that the ‘regimen’ can be more important than the ‘no till’. Still, I think it would be fair to say that the balance of the literature suggests sequestration is at least a possibility.

Even so, I’d like to make four caveats.

First, I’d hope we can all agree that the best form of carbon sequestration is the one where humanity leaves the world’s hydrocarbons in their well sequestered present locations deep down in the earth. Carbon sequestered shallowly in soils by living organisms is always going to be more potentially mobile. You could argue that, in practice, humanity just isn’t going to leave all that energetically useful carbon where it currently lies in the rock, and that we therefore need to think about other mitigation strategies. Fair enough. But David Johnson’s insouciance about continuing to live our present high energy, fossil-fuelled lifestyle while mitigating its effects through shallow sequestration in living soils doesn’t inspire me with a great deal of confidence.

Second, no till farming doesn’t have it all its own way in terms of greenhouse gas emissions, because it’s typically associated with greater nitrous oxide emissions – and in some situations these outweigh the carbon sequestration gains: “increased N2O losses may result in a negative greenhouse gas balance for many poorly-drained fine-textured agricultural soils under no-till located in regions with a humid climate” 15 . That sounds like an apt summary of many of the soils where I live. Proof again, if it were needed, that in agriculture as in many other things there are no one-size-fits-all solutions.

Third, there may be a limit on soil sequestration potential. Regen-ag heroes like Gabe Brown are lauded for taking on farms degraded by over-tillage and soil carbon loss and then building up the soil carbon stocks. But it seems to be the case that you can only build up the soil carbon for so long 16 – we’re talking years, or decades at most – before it reaches an equilibrium where there’s no agricultural benefit to increasing carbon (as the Kaisers have already found) and it gets harder to do so anyway. So there may be a fairly short time-frame in which the carbon sequestration benefits of regen-ag are operative. Experiments like David Johnson’s have also been undertaken under short time-frames so far. Some caution about how much we can extrapolate these findings long into the future is probably in order.

Fourth and finally, we come to the vexed question of how much of the carbon that humanity is adding to the atmosphere can be sequestered in soil. The scientific consensus seems to be something in the region between 7-16% of current emissions 17 – a useful amount, certainly, but not decisive enough to keep the climate change wolf from the door. RAPs like Christine Jones and David Johnson think that the potential is much greater, but frankly I’m doubtful of their claims. Jones appears to have something of a track record of questionable over-estimations of soil carbon sequestration potential of such proportions that it’s prompted even luminaries of the alternative farming movement such as Simon Fairlie and Rafter Sass Ferguson to distance themselves from her claims 18 .

Meanwhile, Johnson argues that since fossil fuel combustion is only responsible for about 3% of the carbon in the global carbon cycle, it’s better to focus mitigation efforts on the biotic side of the cycle. This strikes me as specious. True, there are large natural sources, sinks and fluxes of carbon which dwarf the anthropogenic ones, but these are well-established patterns that aren’t significantly responsible for the radiative forcing we’re now seeing as a result of adding new carbon to the cycle. And if I understand this right, this new carbon, this 3% (I think it’s possibly more than 3% if you consider all anthropogenic causes of radiative forcing), is being added every year. However we tend the soil, can we really expect the existing carbon cycle, its soils and vegetation, to take care of an additional 3% on top of its relatively stable totals on our behalf in each and every year for the foreseeable future so that we can continue flying around the world to go to soil carbon conferences? That’s a very large demand to place on Mother Nature. I suspect she has other plans. If the claim is that on the basis of a few short-term, small-scale, local experiments like Johnson’s we can be sure beyond reasonable doubt that all anthropogenic carbon emissions can be stably sequestered long-term in agricultural soils, then I fear I’m looking at amber turning to red.

This isn’t the first time it’s been claimed we can adopt agricultural practices that will sequester all anthropogenic carbon and banish our climate change woes. Those earlier claims were shown to be spurious 19 . The same outcome seems likely this time around.

I think the basis for this claim is that regen-ag farmers spend less on agri-chemical inputs, presumably without a concomitant decline in outputs. So it’s plausible that the current handful of regen-ag pioneers are making a bit more money just at the moment. But unfortunately markets don’t fix food commodity prices at levels determined by outmoded technical inputs – in fact, they barely fix food commodity prices at levels determined by inputs at all. If they did, I’d be a rich man. So if regen-ag proves itself and spreads, then absenting major structural change in the global political economy, no farmer is going to get wealthy from it, because commodity prices will adjust. In other words, it’ll play out the same way as every other technical innovation that’s enabled farmers to increase yields or reduce inputs without for the most part becoming notably better off. Even David Johnson concedes that farmers will need to be paid in order to adopt his BEAM approach. He says that we shouldn’t expect farmers to bear the brunt of society’s environmentally-damaging behaviours. I agree, though historically they generally have done. Of course, in the long run it’s not sound business sense for Homo sapiens Inc. to erode away all its agricultural soils, so at some level it must ultimately be true that it ‘pays’ to adopt regenerative practices. But in the short-run, while I’m sure some farmers have improved their incomes as a result of adopting regen-ag approaches, I’m not seeing a persuasive argument for how regen-ag will in itself improve farmer income. Another red light.

The main idea here – one debated under my earlier post – is that without a healthy soil biota to transport nutrients readily around, our crop plants are unable to access the range of nutrients (particularly the micro-nutrients) that they need for their full health, with negative consequences in turn for human health. I find this idea intuitively quite plausible, but intuition only takes one so far. Proponents of mainstream agriculture are fond of saying things like “nitrogen is nitrogen”, and to be honest I’ve not seen much evidence to refute them. Evidence of harm to human health from the proliferation of nitrates and other agro-chemicals in the environment is clear, so there are grounds for shifting away from it on that basis alone. But evidence of harm to human health from impaired soil food webs is more elusive. It seems to be the case that the nutrient density of our food is in decline, but it’s possible that this results from eating high-yielding modern crop varieties with poorer micro-nutrient uptake and from a poorer overall diet 20 , not because of the non-availability of micro-nutrients in the soil.

Christine Jones has this to say about the link between current agricultural practices and cancer:

“Not that long ago the cancer rate was around one in 100. Now we’re pretty close to one in two people being diagnosed with cancer. At the current rate of increase, it won’t be long before nearly every person will contract cancer during their lifetimes. Cancer is also the number one killer in dogs. Isn’t that telling us something about toxins in the food chain? We’re not only killing everything in the soil, we’re also killing ourselves — and our companion animals” 21

Let’s unpack these statements a little. In the UK 22 the current cancer ‘rate’ in the sense of new cases of malignant cancer occurring each year across the whole population is 1 in 182, but that translates into the expectation that indeed around one in two people will be diagnosed with cancer in the course of their lives 23 . If by a cancer ‘rate’ of 1 in 100 Jones means that ‘not that long ago’ only 1 in 100 people got cancer at any point in their lives (compared to the 1 in 2 today) I’d like to know how long ago that was. It would certainly be much longer ago than the 20 th century, and the problem is that when you go back that far there are lots of other causes of morbidity – infectious disease and accidents, for example – that confound the attempt to make inferences about cancer aetiologies from rate changes. The fact that cancer incidence in pre-modern populations was low doesn’t necessarily mean that carcinogenicity in those times was concomitantly low (though that might be the case).

The difficulties of inferring changing carcinogenicity from historic incidence rates are compounded by changing age structures. The population now has a larger proportion of older people than before, and since the incidence of cancer is strongly associated with age, a good deal of the increase in cancer rates is purely an artefact of the ageing population. Meanwhile, cancer incidence is currently reducing in many ‘developed’ countries 24 – though as a result of complex, multifactorial influences that push in different directions. So the straightforward answer to Jones’s question – isn’t the secular increase in cancer rates telling us something about toxins in the food chain? – is no, you just can’t infer that. That doesn’t mean she’s necessarily wrong. For all I know, it could be true that there’s a declining intake of micronutrients (or an increase in toxins – Jones seems a bit unclear on this point) with a positive effect on cancer incidence. Though if the finger of suspicion is pointing specifically at the decline of soil food webs, I’d observe that tillage agriculture has been the norm in many places for a long time, so the link between increased cancer incidence today and the destruction of soil food webs seems questionable. In any case, what’s clear is that the evidence Jones cites in support of her ‘toxins in the food chain’ view doesn’t in fact support it. There does seem to be evidence linking high dietary intakes of heavily processed food with raised cancer incidence 25 . Given current dietary patterns, adopting a diverse diet of fresh, unprocessed food may yield more health dividends than a switch to a regen-ag diet.

I’ve dwelt at some length on this rather abstruse cancer issue partly because I think it’s bad intellectual practice to justify an assertion in relation to evidence that doesn’t actually support it, and also because I think sloppiness of this order will easily torpedo the RAPs’ claims about the evidential base for regenerative agriculture more generally as they try to build wider support for regen-ag – and that would be a shame.

I think the health claims for regen-ag currently have to get red light status – though that may change in the future. I find it plausible that numerous aspects of our present food system may be associated with increased cancer incidence. It’s just that I haven’t (yet) seen any plausible evidence linking regen-ag practices to reduced cancer incidence.

I won’t try to summarise what I’ve said above. All in all, my traffic light assessment of the RAPs’ claims suggests to me a few greens, rather more reds, and a lot of ambers. There are numerous reasons why moving towards a regen-ag approach and sequestering some carbon in soils probably makes sense, but there’s a distinct lack of convincing empirical evidence to support many of the stronger claims made by the RAPs. For now, I feel like I’m waiting on amber.

Note: My thanks to Don Stewart for prompting this line of enquiry and to Clem Weidenbenner for an informative discussion.

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