1. Part of Life Part of Agriculture
The Carbon Cycle
Part of Life
Part of Agriculture

2. Acknowledgments Don Reicosky -
Soil scientist with US Dept of Agriculture & Agriculture Research Service
His research provided the inspiration and information for these lessons.

3. Part of all living things (and some non-living stuff)
Carbon

4. Key Words
Photosynthesis
Respiration
Combustion

5. Important Summary Points
Carbon (as CO2) is accumulated…
Photosynthesis uses sunlight to make carbohydrate from CO2.
Carbon (as CO2) is released…
Respiration - carbon is oxidized for energy.
Combustion - carbon is burned
Weathering - rain (slightly acidic) weathers calcium carbonate rocks

6. Carbon Cycle Has Been In Balance for Millions of Years
But in the last century CO2 levels have been creeping up.
Why?

7. Carbon Cycle Has Been In Balance for Millions of Years
But in the last century CO2 levels have been creeping up.
Why? - (burning of fossil fuels).

8. Greenhouse gasses, organic matter and agriculture
Review of Greenhouse gasses
Greenhouse gasses, organic matter and agriculture
CO2 - the main greenhouse gas
Organic matter is mostly carbon
Good soil high in organic matter

9. The Greenhouse Effect Think of the inside of a car in the summer…
UV radiation from
the sun passes
through the glass,
warms up the seats,
and gets trapped
Heat (infrared) doesn’t
pass back out through glass easily

10. Greenhouse gasses
in the atmosphere
act like the glass in a greenhouse or car.

11. The Greenhouse Effect is a Good Thing
Because Mars has almost no
greenhouse gasses, heat from
the sun goes back into outer space. Average temperature = -10 °F

12. Venus has too much of a good thing…
High CO2 levels on Venus
trap too much heat.
Temperature is nearly 800 °F.
Even hotter than planet Mercury (350 °F), which is closer to the sun.

13. Major Greenhouse Gasses
Water vapor Does much to keep planet warm. We have no control over water vapor.
CO2 is the most significant greenhouse gas. Levels increasing because of fossil fuel burning. We should be concerned about this one.

14. Other Greenhouse Gasses
Methane - from wetlands, ruminants and commercial production times more potent than CO2. Levels going up slowly.
Nitrogen oxides (NOx or NxO) - formed during combustion from N2 that’s in air times more potent than CO2.
Chloroflurocarbons (CFC’s) - Foam insulation, refrigeration gas, used to be an aerosol propellant. Being phased out.
Ozone - formed from lightning, electrical arcs, and a reaction of gas vapors and sunlight.

15. This is why we need to work on
CO2.

16. Agriculture & the Carbon Cycle
Organic matter (mostly carbon) affects soil quality.
Crop residues create organic matter.
Manure adds organic matter.

17. How Farmers Can Help
Intensive tillage, burning fuels, use of equipment, adds CO2 to the atmosphere
No-till systems remove CO2. Images courtesy Don Reicosky

18. Why no-till systems are good
Organic matter stays put.
Earthworms thrive.
Root channels remain undisturbed.
Prevents soil from crusting.
Water holding capacity improves.
Nutrient exchange improved.
Crop residues stay on surface.
Soil compaction reduced.
Long term crop production improved.

19. Important Summary Points for
Greenhouse gasses like CO2 help keep the planet warm. This is good. But too much CO2 may lead to global warming.
Agriculture can remove CO2 from the atmosphere if no-till systems are used.
No-till systems also provide a multitude of advantages, and increase long-term crop production.

20. Carbon Sequestration and Carbon Credits
Soon power plants may have to pay for the carbon they emit.
Farmers may get compensated for the carbon they remove from the atmosphere.

21. Remember our carbon cycle
CO2
Photosynthesis
(CO2 + Sunlight)
1/2 ton per acre
Intensive Tillage

22. With no-till, plants put CO2 into the soil and it stays put
Photosynthesis
(CO2 + Sunlight)
CO2
No-till systems

23. Should Farmers Be Paid for For the Carbon They Put Back into the Soil
Should Farmers Be Paid for For the Carbon They Put Back into the Soil? Maybe

24. Here’s an Imaginary Example
Power Plant must reduce carbon
emissions or pay $1,000/day
in penalties

25. So the Power Plant offers to buy carbon credits from a group of farmers.
$250,000

26. Here’s a Real Example
In 2002, Entergy paid $75,000 to Pacific Northwest Direct Seed Association.
This deal was arranged to save (sequester) 3,000 tons of CO2 per year.
6,470 no till acres.

27. No-till really helps - here are some other methods
Deep ocean injection
(being researched).
Oil and gas reservoirs
(use CO2 to push out oil or gas).
Un-mineable coal seams
(replace methane with CO2).
Saline formations
(adsorb CO2 onto salt).
Store as minerals
(magnesium carbonate).

28. Carbon Sequestration Summary Points
We can help the fossil carbon cycle…
By managing the biological carbon cycle.

29. Agriculture’s role in the carbon cycle.
Conservation Agriculture
(Direct Seeding or No-Till farming)
CO2
CO2
Making Soil Out of Oil O2
Agriculture’s role in the carbon cycle.
CO2
combustion
photosynthesis
CO2 O2 O2
respiration
CO2
Credit :
Jim Kinsella,
1998