Soil/Carbon

Carbon Farming

 

"The nation that destroys its soil destroys itself" (Roosevelt 1937)

 

 Carbon is found many places on earth. It is the key element in all living things such as plants, animals and humans.  Carbon is found nearly everywhere on earth. It is found in the atmosphere in the gas carbon dioxide. It is also found in fossil fuels, stored in the ground. It can be found in certain kids of rock and shells of animals. Carbon is also part of the soil and is dissolved in the water such as oceans and lakes. The last place carbon is stored is in plants and trees.

 

How carbon moves between land, water and humans?

 

Land – Plants and trees use carbon dioxide from the atmosphere through photosynthesis. Plants store carbon as they grow, and release carbon and oxygen into the atmosphere through a process called respiration.  When the trees die they decompose and become part of the soil. After long periods of time some of this matter is compacted and transformed into fossil fuels such as oil and coal.

 

Carbon water cycle: Through a process called diffusion, gases containing carbon move between the ocean’s surface and the atmosphere.  So plants in the ocean must use carbon dioxide from the water for photosynthesis. Ocean animals eat these plants to get the carbon they store.  Ocean plants and animals release carbon dioxide back into the water through respiration. When ocean plants and animals die, they decompose in the water. The decomposing plants and animals either sink to the deep ocean and dissolve or settle on the ocean floor where they get buried by sediment. Some sea creatures can remove carbon gas from the ocean water and use it to make their shells. When these creatures die, their carbon –filled shells dissolve or settle on the ocean floor. Also, it takes a long time for rocks to form and wear down. This process also moves carbon in water. Finally water moving between the deep ocean and the surface also carries carbon. Some of the ocean’s carbon then moves from the surface to the atmosphere.

 

How do humans affect the carbon cycle?

Humans influence the carbon cycle through many activities. For instance, we extract fossil fuels fro the ground and burn them for energy so we can run cars, produce electricity, and manufacture goods.  Burning fossil fuels is called combustion. We also contribute to the carbon cycle through “deforestation. When we cut down or burn trees, they can no longer remove carbon dioxide fro the air through photosynthesis. When we burn wood, the carbon in them becomes carbon dioxide and enters the atmosphere. So extraction and combustion of fossil fuels, and deforestation, moves carbon stored in fuel and trees to the atmosphere.  We know that carbon dioxide is a greenhouse gas, so the addition of carbon to the atmosphere can contribute to global warming. It is important to understand the carbon cycle so we can see how human activities may lead to global warming. 

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Soil carbon and soil health

Soil carbon improves the physical properties of soil. It increases the cation (see glossary) exchange capacity (CEC) and water-holding capacity of sandy soil and it contributes to the structural stability of clay soils by helping to bind particles into aggregates. Soil organic matter, of which carbon is a major part, holds a great proportion of nutrients, cations and trace elements that are of importance to plant growth. It prevents nutrient leaching and is integral to the organic acids that make minerals available to plants. It also buffers soil from strong changes in pH. It is widely accepted that the carbon content of soil is a major factor in its overall health. (source http://en.wikipedia.org/wiki/Soil_carbon)

 

Most of the carbon on our planet is stored in plants and soil. Soil carbon is accumulated through the influence of plants and microbes. The reason why increasing soil carbon levels is such a hot topic is that only a 1% increase in soil carbon in 10% of the worlds farm land would absorb all the C02 overload.

 

Practices designed to keep carbon in the soil will benefit farmers, as well as the planet. Carbon adds organic matter, which helps soil retain nutrients and water. Soil carbon also improves the structure of soil, resulting in better drainage and aeration, or flow of gases, for roots. That means healthier plants and better yields for farmers. Previous overuse of inorganic fertilizers has damaged or killed many of the soil microbes over an extended period. The use of organic fertilizers helps return these microbes to the soil to assist with the breaking down of humus to release carbon back into the soil.

 

Sscientists are looking  at ways to sequester, or contain, carbon in the soil and plants. The key to doing this is plant production.


Facts about carbon soil

 

  • FACT: There is already enough CO2 in the atmosphere to drive the earth’s temperature through the critical 2°C level

  • FACT: “Clean Coal” cannot reduce the existing CO2 burden

  • FACT:  Wind and solar power cannot reduce existing CO2

  • FACT: Changing light bulbs cannot reduce existing CO2

  • FACT:  It would take 7 planet Earths covered in forests to absorb the existing burden of CO2

  • FACT: “Soil organic carbon is the largest reservoir in interaction with the atmosphere.” (United Nations Food & Agriculture Organisation) - Vegetation 650 gigatons, atmosphere 750 gigatons, soil 1500 gigatons

  • FACT: A 1% increase in soil carbon in 10% of the world’s farm land would absorb all the CO2 overload


 

 

Managing for catchment health

Much of the contemporary literature on soil carbon relates to its role, or potential, as an atmospheric carbon sink to offset climate change. Despite this emphasis, a much wider range of soil and catchment health aspects are improved as soil carbon is increased. These benefits are difficult to quantify due to the complexity of natural resource systems and the interpretation of what constitutes soil health; nonetheless, several benefits are proposed in the following points:

  1. Reduced erosion, sedimentation: increased soil aggregate stability means greater resistance to erosion; mass movement is less likely when soils are able to retain structural strength under greater moisture levels.
  2. Greater productivity: healthier and more productive soils can contribute to positive socio-economic circumstances.
  3. Cleaner waterways, nutrients and turbidity: nutrients and sediment tend to be retained by the soil rather than leach or wash off, and are so kept from waterways.
  4. Water balance: greater soil water holding capacity reduces overland flow and recharge to groundwater; the water saved and held by the soil remains available for use by plants.
  5. Climate change: Soils have the ability to retain carbon that may otherwise exist as atmospheric CO2 and contribute to greenhouse warming.
  6. Greater biodiversity: soil organic matter contributes to the health of soil flora and accordingly, the natural links with biodiversity in the greater biosphere. 

 

Learn more


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North East Downs Landcare Public Fund

Heritage Building Society

Account Number: 7485182

BSB: 638-080

Learn more

Farm Agronomy

Queensland Water and Landcarers

Condamine Catchment Management association

Condamine Alliance

Landcare Australia