Key factor #11 Carbon Farming and Adaptation to Climate Change

Climate Change is expected to mean the following for Australian landscapes:

1. General increases in temperatures – hotter summers, warmer winters
2. Less rainfall particularly in the south during winter and spring
3. Increased frequency of dry seasons
4. Increased evo-transpiration
5. Greater frequency and intensity of extreme weather events
6. Reduced flows in inland waterways.

The Carbon Coalition contends that increasing soil carbon levels and the processes required to do this are an effective strategy for adapting to and compensating for these conditions.

Increasing soil carbon levels in the 450m Ha of agricultural soils in Australia and the 5.5bn Ha of agricultural soils in the world is also an effective strategy for absorbing excess CO2 from the atmosphere and reducing the severity of Climate Change.

What is Soil Carbon?

Soil Carbon is one of the many resting places of Carbon as it cycles throughout the biosphere (the liveable area on the planet). Carbon is the basic chemical building block of all life on Earth. It also resides in mineral form in rock formations and in fossil fuels, coal and oil as well as in the ocean. The amount of Carbon on Earth is fixed. So the many processes that use it need to access a supply of it and have somewhere to get rid of it. The result is a cycle as Carbon moves between the oceans, rocks, soil, and atmosphere.

There are 33,000 Gigatonnes (Gt) of carbon stored in the oceans, 2500 Gt/C in soil, 750gt/C in the atmosphere, and 650 Gt/C in forests, grasslands, and other vegetation. (The “Greenhouse” effect is caused by the cycle getting out of balance, resulting in the atmosphere housing more on a rolling basis than it was designed to hold in order to manage stable weather patterns.)

Photosynthesis is a process that cycles Carbon out of the air and into plants, to be eaten by animals and humans as well as being deposited in soils. Photosynthesis is the only process that can take CO2 out of the atmosphere. It separates the C atom from the O atoms, releasing the Oxygen and incorporates the C in the plant, or transfers it to the soil where it becomes humus or other forms of Carbon. Some of it is released into the air if plants die and oxidize or dry out, or rot, releasing C in the form of methane.

Soil Carbon takes two main forms: 1. All the decomposed bodies of microbes such as bacteria, fungus, nematodes and root systems that die when plants are grazed as well as other decomposed plant residues. These forms of Carbon can be cycled quickly, within weeks. 2. The Carbon which is incorporated into the soil itself, such as humus. In these forms it can remain stable for thousands of years.

Total Organic Carbon is the amount of C stored in the soil of whatever type, source, or location. It can be measured very accurately. While soil carbon is subject to “flux” – different amounts can be measured according to time of day, time of year, and weather conditions – averaging techniques make assessing the amount of increase or decrease in soil C percentage possible.

A nation’s most precious resource

“The soil organic carbon (SOC) pool is an important indicator of soil quality, and has numerous direct and indirect impacts on it. For example, increase in SOC pool in degraded soils improves soil structure and tilth, reduces soil erosion, increases plant available water capacity, stores plant nutrients, provides energy for soil fauna, purifies water, denatures pollutants, increases soil biodiversity, improves crop/biomass yields, and moderates climate. It makes soil a living ecosystem. Indeed it is a nation’s most precious resource.”

Dr Rattan Lal, “Farming Carbon”, Soil & Tillage Research 96 (2007) Dr Lal is Director, Carbon Management and Sequestration Center, Ohio State University, Columbus, Ohio; Professor of Soil Science, College of Food, Agricultural, and Environmental Sciences, School of Natural Resources, Ohio State University; Liebig Applied Soil Science Award, World Congress of Soil Science 2006; President, American Soil Science Society

The Benefits of Soil Carbon

Soil carbon improves the fertility and health of soil which is the source of life.

Soil carbon increases soil’s ability to transfer nutrients to plants, for greater productivity which can improve farmers’ incomes.

Soil carbon increases soil’s water-holding capacity, holding the water until it can be used by the plants rather than letting it run off into waterways.

Soil carbon increases soil stability which means greater resistance to erosion, which in turn means cleaner waterways.

Soil carbon effect on soil’s ability to hold water reduces recharge to groundwater and can reduce or eliminate salination

Soil carbon also has a direct relationship with biodiversity: soil organic matter contributes to the health of soil microbial ‘wildlife’ and micro-flora which are the very start of the food chain. Greater diversity at this level translates into greater diversity above and below the ground.

Carbon is a major component of soil and catchment health.

Soil Carbon and Natural Resource Management

The greatest interaction between Humanity and Nature takes place in the field of Agriculture.

Farmers control around 65% of the terrestrial surface of the Earth. The land management approach they take has a profound effect on the natural resource base.

Traditional European farming practices were not sympathetic to conditions in the Southern Hemisphere and the result has been losses of productive resources. Eg. Australia is said to have lost at least 50% of its topsoil and that soil has lost 70% of its organic matter in 200 years.

There are two theories for restoring the natural resource base to health:

1. Remove stock and lock it up.
2. Move stock and build it up.

The first theory is popular with those who believe in the possibility of returning to an ‘arcadian past’ when everything was ‘native’ to the environment. But which past and which environment? Tim Flannery in The Future Eaters revealed that the first human invasion of the continent of Australia dramatically changed the flora and fauna by the farming techniques employed.

“Firestick farming” by Indigenous people burnt many species of plant to extinction and hunting saw the disappearance of the megafauna. However, some commentators claim that, prior to 1770, this race of farmers lived in a way that was more sympathetic to the landscape. But which landscape? They were not sympathetic to the landscape they found when they arrived 40,000 years before white settlers. However they lived in harmony with the landscape as they had changed it to suit their practices. They achieved a state of sustainability. But only after a period of disruption.

In following the pattern set by their Indigenous forerunners, White European settlers are still in the disruption stage of their occupation. And now they are seeking to achieve a state of sustainability. Returning to the state of balance that existed in 1770 is not possible. A new state of balance must be sought, that is sympathetic to the natural resource base.

Locking up land and removing stock can lead to ‘bare earth’ and desertification because it ignores the symbiotic relationship between plants and animals. Native grasslands – which covered vast areas of Australia in 1770 – need to be grazed and disturbed by stock, then given time to recover, in order for the mechanism of soil carbon manufacture to operate. Grasses left to go rank “oxidize” (emit Carbon) as they dry out and their shadows keep the sun away from new shoots. Consequently groundcover reduces. And deserts begin. (57)

Instead, a new sustainability which includes increased biodiversity and native species can be achieved by the change to Carbon Farming. Carbon Farmers report increases in species of insects, birds, marsupials, and lizards as well as increase numbers of species of native plants as they transition to the new way of farming.

Allan Savory, winner of the 2003 Banksia Environmental Award, discovered the symbiotic relationship between grazing animals and native grasses. The key to increasing soil carbon is biological activity in top soil. Soil carbon is created by insects and microbes living and dying. They do a lot of living and dying when there is a lot of root activity in the soil – vigorous growth and regular decaying of rootmass. Roots that are continually reaching down deep into the soil and then dying back and retreating. Their rotting remnants feed the microbes which produce the soil organic carbon. This activity is encourage when the plant is grazed, but not entirely, then disturbed and fertilized by the action of grazing animals, and then given a lengthy time to recover its foliage. With this recovery comes the recovery of rootmass and so the cycle goes on. Savory invented a grazing management system to encourage this activity. By “moving” the stock in concentrated groups relatively quickly through a large number of small paddocks, grazing management encourages the growth of plants, soil and soil carbon.

Grazing management is one of the fundamental techniques that make up a new approach to agricultural landscape management known as Carbon Farming.

Carbon Farming and Climate Change

Scientists now believe that Carbon Farming can reduce CO2 in the atmosphere fast enough to avert the very worst consequences of Global Warming. (58)


FOOTNOTES:

57. Allan Savory is a wildlife biologist and founding director of the Savory Center for Holistic Management in Albuquerque, New Mexico. The Zimbabwe-born scientist has won international acclaim for his innovative methods to reverse desertification, now being used successfully around the world. In 2003 he received the Australian Banksia International Award for the person or organization doing the most for the environment on a global scale. Allan’s book, Holistic Management: A New Framework for Decision Making, Island Press 1999, is today in use in a number of colleges and universities.
58. Lal, Dr. Rattan, “Farming Carbon”, Soil & Tillage Research, (6 (2007); “soil Science and the Carbon Civilization”, SSSAJ Vol 71 No. 5 Sept-Oct 2007; “Soil Carbon Sequestration Impacts on Global Climate Change and Food Security”, Science, Vol 304, 11 June, 2004. Dr Lal is President of the American Soil Science Society.