Replenish the soil

On this page..

  1. We really can feed the world
  2. No-till croplands grow fungi and trap carbon in the soil
  3. No-till is practised on a third of US croplands! NOT A FRINGE THEORY!
  4. No-till can use biochar as the ultimate soil repair kit
  5. Rotate cows to create a ‘carbon pump’ into the soil and bring pastures back to life
  6. Grass-fed beef can replace grain fed beef and give America more meat than it currently has!
  7. Pastures can store all our CO2 emissions!
  8. Rotate cows and crops!
  9. Take the pressure off soil with food from other sources

1. We really can feed the world

I am more convinced than ever that we can feed the world. Yes, we need to ‘replenish the soil’, bringing dead industrial soil back to life.  Under Threats we saw that yesterday’s deep tilling industrial agriculture kills the soil, and that the world is losing 100,000km2 of arable land a year!  How do we rescue our soils that are currently drying up and blowing away? The good news is with a little tinkering of the current croplands and livestock grazing systems, we can not only stop arable land blowing away, we can restore it — and save the world from climate change in one restorative move! Lastly, because this is my ‘feed the world’ summary page, we will look at non-soil food alternatives near the end of this list — both current and future.

2. No-till croplands grow fungi and trap carbon in the soil

Headings about crops are gold in honour of corn and wheat, the ultimate goal in no-till farming. This video explains how intensive no-till farming that traps roots and carbon in the soil can bring the soil back to life, raise incredible crops, and earn more money than traditional agriculture per acre.

3. No-till is practised on a third of US croplands! NOT A FRINGE THEORY!

 Harvesting a Thinopyrum intermedium breeding nursery at The Land Institute

The Land Institute has developed an intermediate wheatgrass (Thinopyrum intermedium) grain through its breeding program under Dr. Lee DeHaan, trademarked as Kernza® perennial grain. A perennial grain is a grain crop that lives and remains productive for two or more years. Rather than growing for only one season before harvest, like most grains and annual crops, perennial grains grow year after year. As the first perennial grain crop grown across the northern United States, Kernza is expected to dramatically change agriculture, making croplands multifunctional through the production of both food and ecosystem services.

Compare the size of annual wheat (left) with perennial, multi-year wheat (right).
4_Seasons_Roots.jpg

4. No-till can use Biochar as the ultimate soil repair kit

With nearly magical properties, biochar is so wonderful I have had to dedicate a whole page to it. Please take your time to watch the TED talks I list there. In summary:-

  • Biochar is agricultural and forestry waste that is cooked up in a low oxygen environment (and is not wood ash that you might get from slash and burn farming).
  • It is probably most economic to add to croplands and can help bring crop soil back to life economically.
  • When added to the soil, biochar reduces soil fertiliser requirements by actively sucking in nutrients, storing them for plants and stopping the rain washing nutrients out into rivers.
  • Biochar encourages microorganisms to grow and tiny fungi to multiply through the soil. It’s like the coral reef of the soil, providing a home and backbone for every tiny soil organism and fungi to grow. When the fungi die they release nitrogen into the soil, and then new fungi grows.
  • Normal compost degrades and evaporates the carbon back into the air, but biochar stores half of the carbon permanently in our soils (from centuries to even thousands of years).

In summary: both no-till farming and biochar can bring croplands back to life and increase carbon sequestration in the soil. But what about grazing, which makes up 26% of the (non-ice) surface of the earth!?

5. Rotate cows to create a ‘carbon pump’ into the soil and bring pastures back to life

Joel Salatin’s Polyface Farm (wiki) mimics the way cattle ‘mob, move, and mow’ in the wild to maximise grass health for maximum cattle health. Indeed, recent studies have shown that because we hunted so many of the world’s larger animals into hiding or even extinction, natural nutrient flows have been interrupted. Phosphorus flows are only a tiny fraction of what they were a few centuries ago.

The answer? Rather than trapping cows on the one patch of grass and letting them destroy that grass (and soil), let them move. Manage them in a multi-paddock system, even moving electric wires to guide them each day. This is Adaptive Multi-Paddock (AMP) grazing, aka, Managed Intensive Rotational Grazing (MIRG). The results are that pastures grow higher, with roots that penetrate deeper into the soil. When the cows move through again weeks later, they’re eating much better forage which is better for them. And as the cows mow the pastures down again, the plants go into shock and a corresponding amount of root systems die off below ground — becoming food for micro-fungi in the soil. The plants regrow faster in better soil. This cycle of letting the roots grow deeper into the soil acts like a carbon pump, injecting new root carbon into the soil every grazing cycle. Not only that, but the fungi growth also increases soil nitrogen and water retention. As the MIRG wiki says:-

Resting grazed lands allows the vegetation to renew energy reserves, rebuild shoot systems, and deepen root systems, with the result being long-term maximum biomass production.[6] MIRG is especially effective because grazers do better on the more tender younger plant stems. MIRG also leave parasites behind to die off minimizing or eliminating the need for de-wormers. Pasture systems alone can allow grazers to meet their energy requirements, and with the increased productivity of MIRG systems, the grazers obtain the majority of their nutritional needs without the supplemental feed sources that are required in continuous grazing systems.

How much carbon does this system trap? Science trends explains:-

However, soil analyses showed very high rates of soil C sequestration in the AMP grazing system at 3.59 Mg C ha−1. Overall, this level of CO2 entering the soil more than offset all of the GHGs produced, turning the system into a net C sink of -6.65 kg CO2-e kg CW-1. Carbon negative beef- the proof was in the soil.

Rotating the cows around works. Paddocks should be seen as on a big clock, only returning around to the same spot after 6 weeks. This heals the soil and feeds more cows,  increasing profits for the farm. Regular farms get about 80 cow-days per acre but Polyface farms rotation method gets 400 cow-days per acre using this method. In other words, he can grow about 4 times as many cattle on healthier land, without industrial fertiliser to force the grass to grow, or worse, industrial corn to shove into cattle that don’t really like eating corn in the first place.

Here is Joel Salatin at TED 2012

And here is Michael Pollan talking about Joel Salatin in 2010

Straight from the wiki:

“Salatin bases his farm’s ecosystem on the principle of watching animals’ activities in nature and emulating those conditions as closely as possible. Salatin grazes his cattle outdoors within small pastures enclosed by high-tech, electrified fencing that is easily and daily moved at 4pm to ensure that the animals always have fresh grass; grass has had time, about 100 days, to mature and grow tall, which increases levels of starch. Animal manure fertilizes the pastures and enables Polyface Farm to graze about four times as many cattle as on a conventional farm, thus also saving feed costs. The small size of the pastures forces the cattle to ‘mob stock’-to eat all the grass.

In addition his chickens are housed in portable coops that follow 4 days after the cattle, when flies in the manure are pupating; the chickens get 15% of their feed from this. The chickens while finding the pupae distribute the manure across the field.[3] Salatin’s pastures, barn, and farmhouse are located on land below a nearby pond that “feeds the farm” by using 15 miles of piping. Salatin also harvests 450 acres of woodlands and uses the lumber to construct farm buildings.[4] One of Salatin’s principles is that “plants and animals should be provided a habitat that allows them to express their physiological distinctiveness. Respecting and honoring the pigness of the pig is a foundation for societal health.”[5]

Portable coop

Media Attention

Polyface Farm was featured in the book The Omnivore’s Dilemma by Michael Pollan as exemplary sustainable agriculture, contrasting Polyface Farm favorably to factory farming. An excerpt of the book was published in the May/June 2006 of Mother Jones magazine. The farm is covered in the August/September 2008 issue of Mother Earth News. [6] Pollan’s book describes Polyface Farm’s method of exemplary sustainable agriculture as being built on the efficiencies that come from mimicking relationships found in nature and layering one farm enterprise over another on the same base of land. In effect, Joel is farming in time as well as in space—in four dimensions rather than three. He calls this intricate layering “stacking” and points out that “it is exactly the model God used in building nature.” The idea is not to slavishly imitate nature, but to model a natural ecosystem in all its diversity and interdependence, one where all the species “fully express their physiological distinctiveness.” [7]

The farm is also featured in the documentary film Food, Inc.[8]. Polyface Farm is a participant in Humane Farm Animal Care‘s Certified Humane Raised and Handled program.”

There are a few objections to Polyface farms, such as the cost of the meat and their chickens and pigs eating industrially grown corn, but I answer them here.

Allan Savory’s famous TED talk also recommends that we mimic what nature has been doing with cattle for millions of years, “mob, mow, and move”.

 

Page 12 of his PDF shows the following comparisons of neighbouring properties with the same rainfall and the same soils, with improperly managed grazing (or even banned grazing) on the left, and his managed grazing on the right.

Savory.pngSlate tried to debunk it, but there have been so many peer-reviewed replies and other studies confirming these results (including one I quote below from 2016) that I just cannot take the concerns of the Slate article seriously. Instead, objectors get 7 minutes of this.

There are other ways to ‘stack’ the natural cycles and how animals interact to get more food. White Oak pastures take it a step further, and grow grass fed beef which is then slaughtered on site, giving the farm lots of guts. The guts feed soldier fly larvae that then in turn feed more poultry which then also generate fertiliser for the grass. It’s brilliant!  Grass => cows => guts => larvae => chickens => fertiliser for grass.

6. Grass-fed beef can replace grain fed beef and give America more meat than it currently has!

The numbers are here.

7. World pastures can store all our CO2 emissions!

Let’s look at the USA first. As Teague et al summarise in the Journal of Soil and Water Conservation, 2016 (P162)

Conclusions

Soil is a depletable resource, but production of food for human consumption does not have to deplete the soil. Cropping and grazing practices that build SOC levels and soil microbial communities and functions, and that minimize soil erosion can result in soils being a net sink for GHGs rather than a major source of GHGs, as is currently the case. Effective soil management provides the greatest potential for achieving sustainable use of agricultural land under a rapidly changing climate. Ruminant livestock are an important tool for achieving sustainable agriculture. With appropriate grazing management, ruminant livestock can increase C sequestered in the soil to more than offset their GHG emissions, and can support and improve other essential ecosystem services for local populations. Affected ecosystem services include water infiltration, nutrient cycling, soil formation, C sequestration, biodiversity, and wildlife habitat. Our assessment suggests that increasing SOC globally within food production systems will reduce the C footprint of agriculture much more than reducing domesticated ruminant numbers in an effort to reduce enteric GHG emissions. The simultaneous increase in production of agricultural goods indicates that integrating livestock into mixed agricultural systems and grazing management to increase SOC, biodiversity, and soil quality would enhance resilience of soil and agroecosystems against climate change and extreme events

A primary challenge to the increasing global demand for food is how to increase the scale of adoption of land management practices documented to have a positive effect on soil health. It is essential that scientists partner with environmentally progressive managers at sufficiently large scales to convert experimental data on managed landscapes into sound environmental, social, and economic results that will provide regional and global benefits. Rather than reducing ruminants and encouraging destructive agricultural land use by providing price subsidies and other subsidies, rewarding regenerative agricultural practices that focus on increasing soil C and that lead to greater adoption by land managers is essential to creating a robust, resilient, and regenerative global food production system.

Figure 2.png

The bottom line? North America could sequester about 1.2 Gigatons of Carbon a year. Multiply by 3.67 to convert to CO2, and that’s 4.4 Gigatons of CO2, or 1/8th of the 36 Gigatons CO2 we release each year.

We need 8 times the pastureland to sequester all our CO2. The USA has 2.38 million km2 under permanent pastures in 2008. The world has 35. That’s 14 times the pastureland of the USA, or 1.8 times the land necessary to sequester all our CO2.

Note: this is a wild extrapolation on my part, a real back-of-the-envelope calculation. Global pastures will be very different to the North American pastures studied above. Various pasturelands and ecosystems operate differently and some can store more carbon, while others store less. Nevertheless, the potential to reverse climate change is there, in our soils! The Savory Institute says (Page 3 of PDF):-

This sequestration potential, when applied to up to 5 billion hectares of degraded grassland soils, could return 10 or more gigatons of excess atmospheric carbon to the terrestrial sink annually thereby lowering greenhouse gas concentrations to pre-industrial levels in a matter of decades. This while restoring agriculture productivity, providing jobs for thousands of people in rural communities, supplying high quality protein for millions, and enhancing wildlife habitat and water resources.

Comment: That 50 billion hectares is 50 million square km, more than the 35 million square km total permanent pastures in 2008 because Allan Savory is reversing desertification back to life and creating more pasturelands.

Only a few years ago the idea of adding more cattle to land to fix desertification was a heresy. But as the wiki shows, recent years have seen growing support in the peer-reviewed literature as more scientists confirm these claims.

 

8. Rotate cows and crops!

Do you remember from history how in the later middle ages we used to let fields lie fallow to build up nitrogen in the soil? Then we learned to plant nitrogen-fixing crops in between growing our desired crops, and this is crop rotation. But what about rotating cows and crops? What about sending cows through after harvest to munch on the stubble? Cam McKellar explained to Landine (October 2004) that he:-

  • Used electric fencing to gradually move cattle through sorghum and corn stubble after harvesting
  • “We’ve flown barley over the corn and sorghum before and that keeps something growing in the soil to keep a house going for the microbiology, the cattle go through they eat that out,” he said.  “They then with the hoof action are breaking up that stubble which is very hard to do so otherwise and then as quickly as possible we’re getting another crop in it.”
  • 300 cattle add 4 tonnes of wet manure a day
  • Makes the soil softer, eliminates deep soil tilling which is a “brushfire for the soil” and kills microbiology
  • Worms grow
  • After just a few years it has reduced his chemical inputs by 1/3rd
  • Aiming for higher: “”If I can cut my fertiliser and chemical man by 90% that’ll be a push in the right direction which hopefully will cut my fuel, which hopefully will cut my seed, which hopefully will give the bank man a bit of a shock too,” Mr McKellar said.”
  • Regarding crown rot disease: “”We believe part of the story involved fungus, soil beneficial fungi that live in the soil,” farmer John Kirkegaard said. “These fungi can help to compete and reduce the level of crown rot in the soil,” he said. “We’ve found these beneficial fungi trichoderma they’re called, we found higher levels of trichoderma in soils following break crops of canola compared to other break crops like chick pea and this was associated with lower levels of crown rot and higher yields in wheat following canola. “We believe that maybe part of the reason the disease levels were lower and we’re now really trying to see if there’s any opportunities to increase the level of trichoderma in the system.”  (Eclipse note: biochar produces extra fungi and so could help in the war against crown rot disease).

In this 2014 TED talk, Thomas Rippel shows how biochar can be composted with cow dung to produce all the fertiliser we need.

Radio National also investigated an Australian ‘green cow’ movement where cows were allowed to intensively graze certain patches of field, fertilise it, and then move on to graze the next patch of field: while increasing soil biodiversity and health and this having spin-off effects through the local kangaroo and bird populations.

Other References

Wiki on Soil erosionWiki on Soil conservation, Regenerative Agriculture.
Australian Academy of Science — Feeding the future – sustainable agriculture
News: Positive agriculture news at Worldchanging and enter “agriculture” in the search field

9. Take the pressure off soil with food from other sources!

Giant 3d kelp-farms could feed the world and save the oceans

Australia’s CSIRO made fish-free feedstock for fish farms, saving the oceans from ‘by catch’ trawlers

Eating insects gets 10 times more protein than meat from the same vegetation

We can green the deserts and grow food and energy and cities out there!

Sci-Fi speculative future that may just happen: “cultured meats” might feed the world without killing a single animal?

Stem cell driven, vat-grown cultured meats might one day give us all the meat we could ever eat. The technology is still vastly too expensive, but is coming down in price, especially as our ability to develop better feedstocks improves. (EG: Will they find a way to economically extract the tiny fraction of protein out of the giant kelp farms I mentioned above, and use that as a feedstock for all our meat? Will the oceans replace grazing, allowing us to return grazing lands to forestry, parkland, more no-till cropland or some other use?)

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