Predatory attacks would stampede the grazers; the stampede would open up the soil, the herd’s droppings would act as fertilizer. Well, it all worked well enough in prehistory!
– a commenter
Been thinking how to grow a prairie. I am facing a steep learning curve. There are people who know, and the Prairie Ecologist‘s blog is a very good place to start. And Gabe Brown, a farmer in North Dakota, sows “prairie mimics” of 10 or more different species, eventually harvesting the seeds and letting the grassy, leguminous understory turn the field to pasture.
While I was reflecting on the role of the large herbivores in prairies’ ongoing fertility, it brought to mind something from my post on the wonders of stable humus. Writing it, I had learned that
* for soil to grow, it must be alive;
* for it to stay alive, it must be covered;
* for it to stay covered, it must be disturbed.
Who “disturbs” the soils of the prairies? Small rodents like prairie dogs and meadow voles and mice. Rabbits. Various tiny soil critters. Weather and fire. And last but not least, the large ungulates like deer, elk/wapiti, pronghorn and bison. How exactly do these large mammals “disturb”? I took a look at their hooves.
The coevolution of hooves and grasslands
When scientists talk about this topic, they tell us that those odd horny appendages large herbivores walk on evolved because grasslands opened up new opportunities for fast running, and the ground was hard. But isn’t that only one part of the story?
I am thinking in terms of cooperative evolution. Insects coevolved with flowering plants; the flowers feed them nectar and pollen while the insects return the favor by pollinating. Squirrels eat acorns; in turn, they bury many and forget some, planting new oaks. Grasslands evolved increasingly more nutritious forage for the bison; in turn, the bison evolved appendages whose shape and heft provided the right kind of disturbance for the prairie to thrive.
Looking at the various hooves and their imprints, it struck me that they resemble chisels. They cut into the soil, churn it up, break up crusts and clumps, create pockets to hold moisture, trample old vegetation into the ground. What do humans call such work? Tilling. Cultivation.
Interesting, regarding chisels: the Rodale Institute has developed a crimper-roller that’s designed to trample green manures and old stalks into the ground. The tines work like chisels. Vineyards have available to them a smaller, even more chisel-like adjustable “eco-roll.” And Ames Lab at Iowa State University has produced an imprinter-roller that tries to imitate the hoofprints of passing buffalo, to be used in Colorado prairie restoration. Tries.
Too bad they made it as heavy as 8 buffalo — were they thinking they’d be stacked on top of each other, like a circus act? :/ Which brings me to the question of weight.
Say, how heavy was the aurochs?
The buffalo is the biggest herbivore of the North American grasslands. The more massive ones can weigh about a metric ton (2,200 lbs). The fabled aurochs that roamed the mixed forests and savannahs of the Near East, venerated and hunted by the town-building foragers at Çatal Hüyük, is said to have weighed around a ton as well.
If modern farmers had paid closer attention to what works for nature, they could have stayed within that weight and avoided the nasty soil compaction problems plaguing so many mechanized farms. (They have chisel plows 2 ft deep nowadays, desperate to break up the deep subsoil hardpan… what will they do next, dig up the whole field with a backhoe!?!)
The widely popular Allis-Chalmers Model B tractor that came out in 1937 weighed 2060 lbs, just under a metric ton. But the “biggering” meme did its evil work, so that today we have the Big Bud, a monster of a tractor weighing over 100,000 lbs (45 metric tons). And everything in between. Now that is beyond insane.
I took a peek at various county extension and land college sites; surely they would preach a return to smaller machines for compaction problems? Don’t hold your breath. They advocate “traffic management” despite knowing that the first pass of a heavy tractor over the land does the most damage.
And so it occurred to me that they are caught between the rock and the hard place. If they urged lighter machines, they would be biting the hand that feeds them — all those who profit by selling these huge tractors and implements and give out grants. But worse yet, they would be admitting that the whole biggering paradigm of the last 50 years has been mistaken, and terribly detrimental to soil. In addition, moving to smaller machines would mean moving to smaller farms; only megamachines make megafarms possible. Which in turn would open a giant can of worms: having to address the political economy of food which is biased against smaller producers, and the necessity for land reform. Ouch.
If nature tills the soil (and by the way, in forested environments the wild pig is nothing if not a super tiller), then those much maligned neolithic farmers were not doing anything nature does not do in disturbing the ground to grow plants. The ard (aka scratch plow, basically a pointed stick embellished over time), creates a shallow disturbance where seeds can be sowed.
The benighted moldboard plow was not invented until about 300 BC in China, and 1,000 AD in Europe. So perhaps it was not the disturbance per se that damaged/ruined the soil of the Near East, but something else… and that made me wonder if the whole emphasis on no-till among organic gardeners and farmers has been misbegotten. Given the fact that I turned parts of my Colorado garden soil into a hardpan within a couple of years of no-till despite all the organic matter and mulch I applied, this has been an exciting thought. Gasp. Was Ruth Stout wrong?!
I used to swear by no-till, cringing whenever I had to fluff the soil to put the seeds in, and depriving myself of the joy of burying my hands in the dark crumb. Feeling increasingly hoodwinked, I turned to one of my favorite farmers for enlightenment. Gene Logsdon has written eloquently about his problems with no-till here, here, here and here; you gotta read it to understand the pain. And one does not have to look far on the web to see the extent of the cover up.
As it turns out, no-till farming is not quite no-till. Not only has the chemical industry jumped on the bandwagon, inducing farmers to douse fields with herbicide, but no-till farmers till aplenty — they twist the words, and have invested in all manner of huge machines that churn the land over and over, deeper and deeper, during the growing season, while not being, you know, technically speaking, moldboard plows.
Neolithic soil murder — whodunnit?
So the question offers itself: if intermittent, lightweight, shallow surface tilling is in principle beneficial to the land, imitating the good work of the ungulates, then what killed those Near East soils? Well, deforestation, and in lower Mesopotamia, salinization ruined a lot. But in the grasslands, it was not soil disturbance per se but too much of it. As nature jumped in to cover those bare fields with “weeds,” the farmers fought back with more and more tilling, resulting in more and more bare, carbon-depleted soil, until the soil died and blew away.
Doink. I fell for the all or nothing fallacy, again. If much tilling harms the soil, then no tilling AT ALL must be the answer, right? Wrong.
Last missing piece
All the same, I wondered what might counteract soil erosion in the tween times when even modest tilling renders soil temporarily bare. The answers came readily. Untilled buffer zones such as hedges moderate run-off. But the key to keeping soil in place are soil glues. These are sticky substances that only recently began to receive attention. It is the glues that keep soil crumbly. The crumb in turn forms spaces that readily receive rain, letting it pass into the subsoil and the aquifer. And it’s the glues that hold the soil together in the face of water and wind. (That’s an amazing short video!) And glues abound in living soils.
Earth, water, air, fire
Churning the top layer of the soil invites the alchemical marriage of the four elements — earth, water, air, sun’s fire — and in uniting the above and the below, green life comes forth in profusion.
Anyone can see this in a potted plant. After a while, the soil compacts, water is slow to be absorbed, and the plant — if sturdy — survives in a lackluster sort of fashion. But take a chopstick and dig around a bit, add a few spoonfuls of fresh soil. Water will quickly sink into the fluffed soil bringing with it needed oxygen and other gases, the soil will warm and dry quicker, avoiding water-logging, and the aeration and sunlight will neutralize molds. The plant will spring to life.
Here’s how nature does it:
* for soil to grow, it must be alive;
* for it to stay alive, it must be covered by plants;
* for it to stay covered by plants, it must be tilled.
The Earth is a garden after all. Where are your hoof shoes? Come dance on the land!