I've noticed a slow evolution in paleo-environmentalist dogma regarding land management in general and grazing in particular. Stewart Brand could add this to his list of environmental heresies.

Over the next ten years, I predict, the mainstream of the environmental movement will reverse its opinion and activism in four major areas: population growth, urbanization, genetically engineered organisms, and nuclear power.

Reversals of this sort have occurred before. Wildfire went from universal menace in mid-20th century to honored natural force and forestry tool now, from “Only you can prevent forest fires!” to let-burn policies and prescribed fires for understory management.

Environmentalists still have only the dimmest glimmer of comprehension, so they get the specifics munged up and can't reason usefully from such faulty premises.

The result of conventional agricultural practices such as artificial fertilizing, ploughing, stubble burning, bare fallows, etc is to run down the organic matter in the soil, and it is this organic matter that is the source of stored soil carbon. The main advantages in direct global warming terms (sources/sinks) of restoring soil’s ability to store carbon are that it is immediate, massive and involves capturing excess CO2 from atmospheric circulation. There are additional huge benefits in terms of water retention, drought tolerance, biodiversity increase, cost decreases, etc as well. The immediacy is a result of using the natural biological process of photosynthesis — as the grasses and other plants grow they absorb C02 each and every day. The massive capacity is simple mathematics.

Well, no. Fertilizing and stubble burning doesn't necessarily run down the organic matter in the soil. Fertilizing properly, with proper nutrient balance and timing, hugely increases it. Stubble burning can increase it too, but it is an indirect effect on some soils resulting from PH change from the ashes produced. Ploughing stubble in might have even more direct benefit, but ploughing causes massive outgassing from the soil and so a net loss in soil organic matter. It's important to understand that every agronomic method can be done poorly, or done at the wrong time, or to excess etc. and so have negative impacts on soil carbon.

But the general idea that soil has the capacity to sequester massive amounts of carbon - enough to counteract fossil emissions - is valid. It's a matter of technique.

[Soil carbon can be restored] by actively mimicking nature and thereby allowing natural cycles to reinvigorate. Arid and semi-arid grazing lands co-evolved with massive herds of grazing animals that were kept bunched up by the presence of pack-hunting predators. When humans removed these predators and fenced in the animals we severely disrupted this natural behaviour leading directly to desertification and massive release of soil carbon into atmospheric circulation. The process that actually removes CO2 from atmospheric circulation is photosynthesis.

This is half sensible and half mythical. It is true that good grazing management leverages herd behavior for the benefit of the animals, and the grasses and forbs. But what is emulated by these practices is migration. On open range herds will move continually. They'll graze, trample and foul an area then move on to fresh pastures, and not return until the land has recovered. They can't do that if they are "set stocked" in a fenced area. However, if the fenced area is further divided into paddocks and the animals move from one to another in emulation of migration, the same thing happens on a smaller scale as with the massive wild herds of yore.

Graziers have known all of this forever. Nomadic herders simply move along with their herds. More settled herders use boys and dogs - same thing - to bunch the herd and move it when needed. But, the more arid and less productive the range the more land that is needed to support an animal. It becomes difficult to manage herds over such large areas. It would take a lot of boys and dogs, close association with the herd animals, training from birth in the way of the herd, and ringers - lead animals that are attached to the boys and dogs that will lead and instruct younger animals while maintaining good order.

That culture never developed in the new world - in Australia where the author of the referenced article is from, or the American west. They didn't have enough people and got sidetracked on a dead end extractive cultural system that simply let the animals fend for themselves for the most part, with yearly or seasonal round-ups to extract profit. They were cowboys and drovers, not farmers or shepherds. Though the conditions that nurtured that impoverished methodology were brief, the mythology proved to be durable. More's the pity. They continued with bad management methodology long past the time when it made any sense.

The problem got worse when sod busters came a cropping. They couldn't tolerate animals grazing their fields and the new invention of barbed wire made it possible for them to fence animals out of their fields for a price they could afford. Bit by bit more and more land was fenced off for cropping until finally the free range animals weren't fenced out, they were fenced in. But the cowboys didn't adapt. They had no grasp of the issues of land or animal management, and no inclination to acquire it. You don't even need a horse to manage grazing. Roping and riding are about as useful as flint knapping in the modern world.

Now, with a more technological focus steeped in knowledge of soil, grassland plants and grazing behaviors, and a few new technologies such as electric fences, it is possible to not only emulate natural grassland systems, but also improve on them. But it ain't ranching in the old sense and cowboys hate it. Practitioners call themselves grass farmers or graziers. Their objective is to be smarter than a cow, not tougher.

The incentives change. In managed grazing the incentive is to improve the productivity of the range - its stocking rate. That reduces the cost of fences and inputs relative to the benefits. Doing this well over time results in a monotonic increase in soil quality, especially soil organic matter. And that has atmospheric implications.

This simple picture says it all — if we allow the grasses to express themselves to the stage shown on the right they absorb CO2 from atmospheric circulation and turn it into plant material. We then manage our grazing animals to eat the grass down to the level somewhere between the middle 2 grass plants. At this point the reduced leaf mass is unable to support the large root mass, and so the plant sloughs off the now excess root material (carbon). The plant then commences to regrow but critically it regrows using carbon absorbed by photosynthesis, not the carbon it previously sloughed off. Repeat this process and you in essence "pump" CO2 out of the atmosphere and store it underground.

Yes, but for how long? Carbon in organic form is food for soil critters. The plant carbon pump may run faster, but the microbial digesters and emitters speed up too. The size of the working set increases, and so there is more carbon in the soil at any given time, but it's still in play and cycles back to the atmosphere rather than accumulating. It isn't durably sequestered. It's a tread mill you can never step off without losing what has been gained. That's good, but we can do better.

"terra preta" is probably the best example of just what we are talking about — a carbon rich, biologically active soil created as a result of appropriate human management. In the 5 billion hectares we want to bring attention to the results will not be as dramatic due to the lower rainfall and inherently poorer quality of the soils themselves, but the results will be significant and well worthwhile.

The basis of terra preta is chared carbon, not organic carbon. That form of carbon is durable. A thousand years later it's still there. But it is chemically active in myriad beneficial ways that hugely improves the fertility of soil and so its load of organic carbon. The size of the working set is increased and the char is durably sequestered. If you want to make good use of crop stubble or the slash from forest understory management that Brand spoke of way back at the beginning of this post, then turn it into biochar with low temperature pyrolysis and amend your grasslands with it.

It appears that the pre-industrial level of atmospheric carbon dioxide was 280ppm, and that globally we are now at 455ppm, and heading towards 550ppm. To get from 550ppm back to 280ppm, 270ppm must be removed. Globally, a 4.2% increase in SOM would potentially reverse the expected situation.

Well, I think current levels are still less than 390ppm, but the idea has legs. The soil can easily absorb all the carbon we need to send co2 levels plummeting. We could even drop them below historic levels if we get carried away. It isn't a quick fix, and it isn't a once off fix, it's a process that would have to be continued until we no longer needed to live off the land and gave up agriculture. It has the virtue of solving several problems at once though. We need to increase production of food and fiber, and we need to reduce GHGs. We need to make more effective use of inputs such as water and fertility. And we need to do it all on less rather than more land. Soil carbon management for both cultivated and grazed lands will do this.

Update:

Another angle.

Applying organic fertilizers, such as those resulting from composting, to agricultural land could increase the amount of carbon stored in these soils and contribute significantly to the reduction of greenhouse gas emissions, according to new research published in a special issue of Waste Management & Research (Special issue published today by SAGE). . .

“An increase of just 0.15% in organic carbon in arable soils in a country like Italy would effectively imply the sequestration of the same amount of carbon within soil that is currently released into the atmosphere in a period of one year through the use of fossil fuels,” . . .

Composting can contribute in a positive way to the twin objectives of restoring soil quality and sequestering carbon in soils. Applications of organic matter (in the form of organic fertilizers) can lead either to a build-up of soil organic carbon over time, or a reduction in the rate at which organic matter is depleted from soils. In either case, the overall quantity of organic matter in soils will be higher than using no organic fertilizer. . .

Their results suggest that soils where manure was added have soil organic carbon levels 1.34% higher than un-amended soils, and 1.13% higher than soils amended with chemical fertilizers, over a 50-year period. “This is clearly significant given the evaluations reported above regarding carbon being lost from soils, and the increasing amount of carbon dioxide in the atmosphere,” they say.

It's better to return organic matter to the fields it came from than to use it in some other way, so long as it isn't contaminated with heavy metals and such. It's interesting to note that in the example from Italy used above that carbon emissions could be negated every year for 50 years while increasing SOM less than 2%. The soil's carbon capacity is immense.

These folks are thinking of waste management. The idea that their crap isn't a problem to get rid of so much as a solution to emissions problems must be exciting for them, especially if they can get paid for doing it - credits and subsidies and such.