Monday, January 21, 2008

Carbon Farming and Natural Resources

Carbon Farming is not a new practice. It is a new way to describe a collection of techniques which can increase soil organic carbon in agricultural land. Land management practices that encourage healthy, growing soil microbial communities and, in so doing, create soil organic carbon and strengthen the natural resource base, include the following:

100% groundcover 100% of the time - This is a Carbon Farmer’s goal. Soil
covered by plants cannot be blown or washed away. It is cooler and more attractive to microbes than if it was exposed to the sun. Therefore overgrazing, (or “flogging the land”, in Australian parlance) and burning grasses and stubble and ploughing are anti-carbon actions. In fact, they release tonnes of carbon into the atmosphere. These practices, along with clearing native
vegetation, have put Agriculture in 2nd place, behind coal-burning power stations, as the biggest source of Australia’s Greenhouse Gas emissions.

Grazing management – Stock are concentrated in small paddocks for short periods (days) so that they graze evenly and at the same time till the soil with their hooves, stomping old grass and manure into it. The plants are then left to grow a full head of foliage so that their roots go down as far as possible into the soil. When they are grazed, the roots die back upwards in proportion to how much of the foliage was eaten. Overgrazing can cause the roots to shrink so short they struggle to get started again. So short grazing periods and long periods of rest are best.

No till cropping – Ploughing disturbs the microbes and dries out the soil. It also releases tonnes of CO2 per hectare. No till techniques sow the seed in the top soil without tearing off the existing foliage or applying herbicides which are also bad for microbes. There are several no till techniques, including “Pasture Cropping” and “Advanced Sowing”. The one direct drillsthe seed into pasture while the other slices a line through the pasture and inserts the
seed. The crop grows up above the pasture and can be harvested or grazed. The pasture usually thickens and grows more vigorously after such treatment.

Mulching – This takes two forms: 1. Covering bare earth with hay or dead vegetation. This protects the soil from the sun, cools it, and attracts soil-producing microbes. It also holds water where it can be used instead of letting it run off immediately. 2. Cutting down and dessicating tall, dead plants and thistles to form a layer of litter on the soil and allow the sun to penetrate and foster plant growth. Gardeners know the value of mulching.

Water management systems – Water is essential to the carbon growing process. Several systems have emerged for maximising us of water that falls on a farm. Two names are prominent: Natural Sequence Farming (NSF) and Yeoman’s Keyline System. NSF slows the flow of water through the landscape by returning eroded gulleys and creeks to swampy meadows and chains of ponds that they were when white settlers arrived. The water stays long enough to make more grass and plants grow, rather than rushing down widening gullies carrying the topsoil away. NSF is based on the natural topography of the land. So is Keyline Planning. It uses the shape of the land to determine the layout and position of farm dams, irrigation areas, roads, fences, farm buildings and tree lines. Both methods increase soil fertility and carbon.

Biodynamics – This is a method of treating soil, based on the theories of mystic and theorist Rudolf Steiner. He postulated that vital forces or energies flowed throughout the universe and that these can be harnessed to increase plant growth. Biodynamics adopts a homeopathic approach to preparing natural fertiliser and times activities to align with cycles of the moon and the stars. Many ordinary, sober farmers report great results with biodynamic preparations

Biological Farming – This is the umbrella term for the use of natural compounds to stimulate biological activity in the soil. These compounds range from compost teas (concocted after an analysis of the soil for deficiencies), worm juice (active enzymes created from worm castings), Biosolids (human effluent which needs to be plowed into the soil for hygene and odour reasons (not a favourite of carbon farmers), Nitrohumus (treated human effluent, needs no ploughing) etc.

Composting - This largely involves breaking down manure into a rich humus ready to spread on the fields. There is also a growing movement for recycling green wastes from cities for use on agricultural lands.

Trees – Trees scattered across grasslands (“Grassy woodlands”) provide shelter for stock and wildlife and also have the effect of causing the soil adjacent to be richer in carbon. They can also assist in the management of water movement. And they contribute directly to increase yields and productivity in both livestock and crops, with reported increases of between 20% and 40%. (Footnote 11)


11 Gillespie, R. (2000) Economic Values of Native Vegetation, Background Paper Number 4, Native Vegetation Advisory Council, Sydney. Lockwood, M., Walpole, S.C. and Miles, C.A. (2000), Economics of remnant native vegetation conservation on private property, LWRRDC Research Report 2/00, LWWRDC, Canberra. Miles, C.A., Lockwood, M. Walpole, S., Buckley, E.(1998) Assessment of the on-farm economic values of remnant native vegetation. Johnstone Centre Report No. 107. Johnstone Centre, Albury. Walpole, S.C. (1999), Assessment of the economic and ecological impacts of remnant vegetation on pasture productivity, Pacific Conservation Biology, 5: 28-35.

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