Friday, November 20, 2009

Cornfield vs. Pasture

Greg asked me if its possible to grow field crops without animal input and still build soil.

Regardless of input, I know of no one who has developed a way to grow field/row crops and build soil. The best integrated systems just maintain topsoil.

These pictures illustrate why row crops always damage the soil, whereas a stocked and well-managed pasture builds soil.


Image source: Seaburst.com

When we raise crops, we expose long rows of soil. We struggle to keep these free of "weeds" whose natural job is to secure the soil. We can't stop wind and water (rain), which inevitably course through these furrows carrying soil away from the field. The roots of these crops reach shallowly, so they don't trap rainfall efficiently. If managed very intensively with manure, rotation with leguminous cover crops, and mulch with compost, at best we can replace the soil lost each time we plant with row crops.

In contrast, a pasture looks like this:

Image source: Rebelwoodsranch.com

The soil accumulates year after year because the tight root structure and full cover of grasses and "weeds" protects it from wind and water erosion. The roots themselves draw the water (rain) into the soil. The grass constantly takes carbon dioxide out of the atmosphere, converting it into carbohydrates, stored in the root system. Ruminants are an essential part of perennial grass land ecosystems, providing many services to the grass including fertilization with nitrogen. The grass feeds the soil, the soil feeds the grass, the grass feeds the ruminants and the ruminants feed the grass.

In short, a field of row crops requires a constant battle against natural processes, and its very structure involves us in a largely unsuccessful battle to preserve the soil.

It reminds me of a passage in the Tao Te Ching (Chapter 29):

Does anyone want to take the world and do what he wants with it?
I do not see how he can succeed.
The world is a sacred vessel, which must not be tampered with or grabbed after.
To tamper with it is to spoil it, and to grasp it is to lose it.

14 comments:

Charles R. said...

Good post, Don.

Who woulda thunk that us (grass-fed) meat-eaters would end up being the more informed environmentalists?

Jim Purdy said...

Interesting contrasting pictures, and very good explanations. Thanks!

Greg said...

Don, thanks for blog post response, it was very informative for me. You are making a very convincing case that farming with exposed topsoil is fundamentally flawed.

It seems we should assume that the plants we eat come from these sources, even if they are organic, and that it is more destructive to the environment to eat grain fed meat, but good for the environment to eat pasture raised meat.

I am still wondering, though, if there is a different way to raise plants for human consumption (permaculture?) with or without animals in a way that builds soil.

Don said...

Greg,

I think your question refers to horticulture rather than agriculture. So long as you return to the soil more organic matter than the plants remove, and you protect it from wind and water erosion, you can grow plants (vegetables and fruits) and increase topsoil. I think permaculture techniques aim at this but I don't know of data showing them effective at increasing topsoil.

Andy said...

Erosion is one thing, but another thing is how agriculture depletes the soil from nutrients. Then they use fertilizers made from oil. This can't be too environmentally friendly and energy effective. You need to drill the oil, transport it, create the fertilizer from it, transport again etc. In the end the ratio of energy used to energy returned gets pretty bad.

Is a pasture self-sustainable? I mean, the grass uses nutrients to grow, which are then eaten by cows. So over time, they would need some fertilizing too? Or they just change pasture land and let the old place recover?

Don said...

Andy,

So long as animals graze on the pasture, it is self-sustaining. The animals urinate and defecate, which feeds the grass with nitrogen, minerals, etc.. They die and their bones etc. go back into the soil (or humans can return the bone meal to the soil). The grass feeds the animals and the animals feed the grass. Also, remember that pasture also includes many animals besides ruminants all of which play roles in nourishing the soil (worms, insects, birds, rodents, etc.).

Remember, pastures a.k.a. savannahs/grasslands arose spontaneously in nature without any human intervention, through the spontaneous coevolution of many species. The integration almost boggles the mind.

simonmoakes said...

There is a great book by Graham Harvey - The Carbon Fields about the benefits of restoring arable land to grassland around the world, and the health advantages of eating pasture-fed meat and dairy (maybe not too much dairy on paleo), but a correct ratio of Omega 3 and 6. Article published last year in the UK, linked to the book:
http://www.guardian.co.uk/environment/2008/nov/05/cereal-crop-farming-wheat-prices

Santiago said...

I'll strongly recommend you the ideas of Allan Savory, wrt to grassland management and restoration, based on historical patterns of herd behaviour.

There's a preview of his best known book at google books here: http://books.google.com/books?id=MPx0jrDqDo4C&printsec=frontcover&source=gbs_v2_summary_r&cad=0#v=onepage&q=&f=false

These links maybe of interest, also:

http://www.greenuniversity.net/Ideas_to_Change_the_World/AllanSavory.htm

http://www.holisticmanagement.org/n9/about/carbon.php

http://www.holisticmanagement.org/n9/Results/data_and_docum.php

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SOMA said...

In response to your sentence: "Regardless of input, I know of no one who has developed a way to grow field/row crops and build soil. The best integrated systems just maintain topsoil."

You should look up some of Masanobu Fukuoka's literature. A brief explanation of his methods is here: http://www.permaculture.com/node/140

He did in fact build much topsoil using methods he discovered (or rather, not using methods that have guided traditional/conventional/organic agriculture for many years). He did this with very little input and labor, and lived to be 95 years old. He was a rice/barley farmer with orchards of apple and citrus, among many other bumper crops. He did no weeding, he never plowed his soil, he seeded all plants directly, and he never fought disease or pests with human effort. He preferred to let natural selection build his land, and he was able to get yields as good as or better than traditional/conventional rice farmers all over Japan. His book "One Straw Revolution," is a nearly complete layout of his philosophies, not only on farming, but on the nature of life and the world at large. It is truly a revolutionary work which deserves to be acknowledged. His books are still available, and if you e-mail me (david.rafael.bonilla@gmail.com) I can send you "One Straw Revolution" as well as his more detailed account of his "natural" or "do nothing" farming methods.

Don said...

SOMA,

Already read One Straw Revolution many years ago, along with his other book, the title of which I don't presently remember (Natural Farming?).

Not sure how much soil he built, compared to the Salatin system. His method worked because he allowed the land to return to a native grassland ecosystem. By allowing weeds to grow he stopped erosion. So Fukuoka did not practice row-cropping methods. Much better than row cropping and it does allow cultivation of cereals without the attendant land erosion. I don't remember if he returned human waste to the soil, which I think is necessary to complete the cycle, in absence of ruminants. Again, I don't know how it compares to Salatin's system in soil production, but I would guess it works more slowly due to the absence of the invigorating effects that ruminants have on grassland due to their walking around and depositing urine and feces. Thanks for reminding me of his work.

SOMA said...

Thank you for your reply. It is very true that his methods never implied "orderly" row cropping. I feel I can refresh your memory on his work because I read his books only a year ago.

1. He claims in "One Straw" that he built at least a foot of topsoil over 30 years as a result of not plowing the soil combined with mulching the rice straw (nature mulches, but never composts)

2. He did not return human waste to the fields, but did compost it, and used it in his smaller gardens. The only fertilizers in his fields were his leguminous ground covers (which applied to the orchards as well) and the ducks' wastes that he introduced into his patties at certain times.

3. You are probably right about Salatin's method being quicker in building top soil. Grain production, even Natural Farming, cannot compete with responsible animal husbandry in terms of speed of topsoil production. But as Fukuoaka would say, it is important to "have the mind of a child" when it comes to these things. Provided the fields are not plowed and left to proper management, the top soil will grow indefinitely.

As well, he says that before he would begin cultivation of difficult clay soils, he would dig bamboo under the soil to leave organic materials that would break down over 7-8 years time.

Thank you for posting this information freely for everyone to see. It is an inspiration to me and the friends I have shared it with.

On an unrelated note, I sent you an e-mail earlier this morning (forgive my impatience) asking about whether quinoa (not truly a grain) had a place in the paleo diet. If you could answer that question for me here I would much appreciate it.

-David

Don said...

David,

Sorry, I got your name wrong on the other comment. I don't consider quinoa a paleo food. The caloric return for harvesting quinoa seeds would fall well below harvesting tubers in a primitive circumstance. In addition, quinoa has saponins that damage gut wall integrity.

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