Monday, January 21, 2008

Soil Carbon and Natural Resource Management

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

Farmers control around 60% of the terrestrial surface of the Earth. The land management approach they take has a profound effect on the natural resource base. (Footnote 6) 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. (Footnote 7)

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. (Footnote 8) “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.

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. (Footnote 9 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. (Footnote 10) This activity is encouraged 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.



6. Mayeux, H., Foreword, Follette, Kimble, & Lal, The Potential for US Grazing Lands to Sequester Carbon and Mitigate the Greenhouse Effect, Lewis, 2001
7. Dr Christine Jones,, “Aggregate or aggravate? Creating Soil Carbon”, YLAD Living Soils Seminars: Eurongilly - 14 February, Young - 15 February 2006. ° Lal, R., “Soil Carbon Sequestration in Latin America”, in Carbon Sequestration in Sils of Latin America, Haworth, 2006. ° Percentage losses of organic carbon from Australian soils, already low in carbon compared to European soils for example, varied from 10–60 per cent over 10–80 years of cultivation. Russell JS and Williams CH (1982). Biogeochemical interactions of carbon, nitrogen, sulphur and phosphorus in Australian agro-ecosystems. In The Cycling of Carbon, Nitrogen, Sulphur and Phosphorus in Terrestrial and Aquatic Systems. (Eds LE Galbally and JR Freney) pp. 61–75 (Australian Academy of Science: Canberra). "More than 75 per cent of Australian farming soils have organic carbon contents less than 1.75 per cent, indicating a widespread need to improve soil organic matter concentrations." Dr Brian Tunstall, Environmental Research and Information Consortium, and formerly with CSIRO. James Porteous and Steve Davidson, “Saving the life of farmland soils”, ECOS, DEC/JAN 2007, CSIRO ° Brian Tunstall calculates that an average organic matter increase of 2 per cent to a depth of 30 cm, achievable in many clay soils, represents a sequestration of 35 tonnes of carbon or 128 tonnes of CO2 per hectare … and there are many hectares of farm land.. James Porteous and Steve Davidson, “Saving the life of farmland soils”, ECOS, DEC/JAN 2007, CSIRO ° Estimates of pre-clearing soil carbon levels in Australia range from < 10 t/ha to 30 cm depth in arid areas to > 250 t/ha to 30 cm depth in highland areas of the Southern Alps and Tasmania and coastal swamps. Adrian Webb (Editor), “PRE-CLEARING SOIL CARBON LEVELS IN AUSTRALIA”, National Carbon Accounting System Technical Report No. 12 Australian Greenhouse Office, March 2002
8. Flannery, T., The Future Eaters, Reed, 1994
9 . 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.
10. There are cities and towns and villages, whole societies living down under the soil. They are connected by highways and contain millions of creatures just trying to make a living, from one-celled bacteria, algae, fungi, and protozoa, to nematodes and tiny microscopic spiders, to earthworms, insects, and ants. Dr Jill Clapperton, “Managing the Soil as A Habitat,” Canadian
Rhizosphere Ecologist, South Australian No Till Farmers Association Conference, February 2007.

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