Carbon, land management, and soil and agricultural practices: strategies and results

March 7, 2016

Illustrating low carbon farming Soil-Association-Low-view-text-960Lately I’ve been reading Fred Pearce’s excellent book on Land-Grabbing: The New Fight Over Who Owns the Earth.  US-style industrial farming practices have spread along with the land-grabbing, with implications for carbon-processing space in the atmosphere that rival the loss of space and homes for the indigenous people and public worldwide, whose land has been stolen. More positive stories and results are captured in italics in the boxes below.

Carbon

Carbon emissions from fossil fuel burning represent less than 3% of the net annual flow of carbon into the atmosphere. The other 97% also results from combustion reactions—respiration, decay of organic compounds, and burning of biomass. These reactions emit carbon and yield energy.

The right hand bar below represents the flow out of the atmosphere. This is driven by the photosynthesis of green plants (including ocean phytoplankton). Photosynthesis is the reverse reaction: consuming solar energy, plants take in carbon, and store both carbon and energy in complex organic compounds.  The difference between the two flows is less than 3%. This makes the fossil-fuel contribution loom large in the ongoing accumulation of atmospheric carbon.

IPCC farming HofAug07fig2

The rest of the carbon cycle is also controlled or influenced by human decisions.  In addition to deforestation and use of fossil fuels, there is human influence over the growth, decay, and combustion of plants.  For thousands of years, long before we discovered fossil fuels, people have been burning and oxidizing carbon compounds that were formed by photosynthesis, cutting down and burning trees, or burning grass, brush, or crop residue.

Less obvious but more significant is the release of stable soil carbon to the atmosphere through plowing and other forms of soil exposure, whereby aerobic microbes rapidly oxidize or “burn” the carbon compounds. Today our soils still contain twice the carbon that the atmosphere does, and these historic and prehistoric losses of soil carbon to the atmosphere can only be guessed at.  Tillage continues worldwide; however, progressive farmers and graziers have accomplished some spectacular and rapid reversals of this soil carbon loss, at little additional cost. In some cases such shifts were a byproduct of their efforts to maintain or increase production while decreasing their dependence on fossil-fuel inputs such as fertilizers, chemicals, and tillage. Unlike vegetation (even trees), the carbon in soil organic matter is fairly stable, lasting more than a  generation on average.

Pasture cropping

Colin Seis, an innovative grain and sheep farmer near Gulgong in Australia, has doubled the organic carbon in his soil in little more than a decade. He didn’t set out to do this. In order to make his operation profitable, and to regenerate the fertility lost by a century of misguided farming practices, he began sowing cereal crops directly into perennial pasture, thus combining farming and intensive grazing while reducing herbicides and tillage. Profits increased because inputs decreased. Another thousand Australian farmers are following his lead, and the system is spreading to North America and Europe.

“The hardest thing to change is your head. Once you’ve done that, the rest is easy,” he says. “Don’t spend a cent,” he advises farmers. “Throw away your disc plow. Put your animals into large mobs and start moving them around.”

These approaches increase photosynthesis while slowing decay or respiration.  Such management  enhances and works with biospheric processes instead of going to war against them.  Documentation is relatively scarce, but it is increasing.  With good land management, photosynthesis can turn atmospheric carbon into valuable soil organic matter, using free solar energy.  Photosynthesis already captures far more energy than all the world’s mechanical power.  Meanwhile, unintentional soil loss is the USA’s biggest export, far surpassing even empty shipping containers, making much agricultural “production” really consumption.  US Farm policy has a particularly large effect on carbon, as it turns out, subsidizing short-season annual row crops such as corn and soybeans, and a style of agriculture that keeps mostly bare ground between plants and between crops. Nebraska and Iowa look impressively green in July and August, but much of the rest of the year they are brown, with few perennial plants growing.

global-carbon-storage_Ruesch-and-Gibbs-2008

Carrying capacity

On his small grassland farm in Virginia, Joel Salatin produces more pounds of beef, chicken, eggs, pork, lamb, and rabbit than most conventional farms or extension agents would consider possible. He does this with few outside inputs, and builds soil, organic matter and carbon, and increases fertility in the process.

Salatin’s methods are described in Michael Pollan’s book The Omnivore’s Dilemma. Salatin produces such quantity and quality by working with and enhancing the biospheric processes such as water cycling, nutrient cycling, solar energy flow, and synergy among species (rather than separation and confinement). By selling his products directly to his loyal customers, he makes a white-collar income from his 100+ acres of grass.

The Farm Bill encourages the heavy use of fossil energy in agriculture by favoring high-yielding monocultures dependent on nitrogen extracted from the atmosphere by fossil fuels, plus herbicides and pesticides. This nitrogen (usually anhydrous ammonia) contributes to the “burning” of soil organic matter, compounding the debt.

Water

Among greenhouse gases, water vapor is the gorilla. While carbon dioxide may be the primary driver of global warming, there’s more water vapor than other greenhouse gases, and it traps lots more heat. Yet the world’s soils, even in their increasingly exposed and dried-out state, hold five times as much water as the atmosphere.

With the loss of sponge-like organic matter, soils lose much of their ability to absorb and retain water. At the soil particle level, it’s like the difference between a brick and a balloon. You can wet a brick, but you can put a liter in a balloon. For the difference over an acre, add lots and lots of zeroes.

Large-scale land clearing and tillage, along with the continued desertification of rangeland soils, lets an invisible Columbia River’s worth of water evaporate skyward from the soils of the American Southwest.

1 - soil graph

Estimated CO2e saving from adopting low carbon nutrient and manure management practices.

 

The Rafter F

After taking a course in the Holistic Management decision framework, Roger Bowe made big changes on his ranch in eastern New Mexico by transforming his grazing management. Instead of continuously grazing his herd over a wide area, he bunched them so as to intensify grazing and then give the plants an adequate recovery period. Careful monitoring of the soil surface conditions enabled him to adjust his grazing for best results. Over ten years, plant cover doubled, undesirable snakeweed declined by 90%, and pounds of beef produced per acre more than doubled. His costs decreased significantly, giving him more profit.

“The words water cycle, mineral cycle, energy flow, and succession became the words we used to describe the landscape,” Roger says. “This is like a foreign language to most ranchers and it is sure not what I was taught in school.”

With less bare soil, rain infiltrates better, less of it evaporates, and more is available to grow plants and recharge groundwater. A well on the property that ran dry in the 1950s came back with 10 feet of water in it. Roger says that during a heavy rain from a thunderstorm, his rangeland soils can absorb two inches of rainfall before it begins to flow across the surface. On similar land, managed in a more conventional way, rain began running off after only half an inch.

Legal protections prohibiting human use won’t fix this situation, at least not on a timescale that matters to us or our descendants. What has proven to get more water in the soil in these environments is intensive grazing, carefully managed for adequate recovery periods for vegetation, before grazing comes around again.

Rangeland plot-comparison3 - carbon

The opportunities

Reducing fossil fuel usage is key, and transforming both our energy systems and efficiency is a huge opportunity to create millions of good jobs, revitalize our economies, and move toward a positive future rather than merely try and avoid a negative one.

We will also need to look beyond technology to the way we manage land, to work in concert with natural processes for carbon cycling and water and carbon conservation—which support and sustain our life.  Transforming human land management is a tremendous opportunity that promises multiple, simultaneous benefits: more and better water for all, revitalization of rural economies, a more sustainable food system, and enhanced human and environmental health. Taking full advantage of this opportunity will involve new paradigms and a new politics.

If we regard nature as a kingdom or category separate from humanity, the human is often seen as a habitual criminal who can be counted on to vandalize nature for personal gain. Many prosperous developed countries have adopted a policing role intended to protect nature from the human criminal.

Zoetvlei

Near Vryburg, South Africa, rancher Sandy Speedy has been keeping records of rainfall and kilograms of beef produced since 1972. Using the Holistic Management framework, Speedy and his family have tripled the amount of beef they produce from an inch of rainfall—by managing grazing to increase soil cover, water infiltration, and soil moisture.

“The limiting factor is not rainfall, as we have been told, but management,” Sandy Speedy says.

The South African government has done away with agricultural subsidies, which Sandy says will be “better for the soil, for the water cycle in a country short of water, and for the agricultural community. It is an opportunity for sound agricultural management.”

Though it may be a necessary stage of development or a process of maturity, this cops and robbers game offers little opportunity for creating the kind of land management we need on our working landscapes. For this we need to move in the opposite direction—toward the results we need rather than just punishing what we don’t want. This means incentives and opportunity for the farmer, the villager, the grazier, the peasant to enhance these basic biospheric processes. By tying incentives to results, rather than practices, we could empower people to come up with their own creative, locally adapted, low-cost methods.

The land management we need, and that provides such an opportunity for addressing both desertification and global warming, brings with it a new paradigm, a new understanding of the foundation or center of gravity of what we regard as nature. This new understanding is at odds with the scarcity-based, zero-sum beliefs and behaviors of both industrial agriculture and protectionist strategies that would remove pastoralists from the land.