| ASSUME | |||||||||
| Fixed Bulk Density = 1.49 g/cm3 | |||||||||
| 1 ha 0-6" or 0-15 cm = 2241653 kg | |||||||||
| 1 ha 0-12" or 1-30 cm = 4483306 kg | |||||||||
| Percent Organic Carbon = (Organic Matter-0.35)/1.80 Ranney, 1969 | |||||||||
| 60%of C in organic matter converted to CO2 (Brady and Weil, 1996, page 377, Prentice-Hall) | |||||||||
| Mass of Earths Atmosphere 5.0 E18 kg (Wild, Soils and the Environment, 1993, Cambridge University Press) | |||||||||
| No loss of CO2 from atmosphere | |||||||||
| 3% OM = (3-0.35)/1.80 = 1.47% Organic Carbon lost | |||||||||
| 0.0147 * 2241653 = 32952 kg Carbon lost/ha 6 " deep | |||||||||
| 0.0147 * 4483306 = 65904 kg Carbon lost/ha 1 foot deep | C= 12, CO2 = 44 (32+12) | ||||||||
| 1GT = 1.0E9 ton | 44/12= 3.67 | ||||||||
| 1GT = 1.0E12 kg | |||||||||
| Depth of Soil," | Carbon lost, kg/ha | Cultivated ha, World | Total C lost, kg/total cultivated area | Total CO2 lost, kg | GT | ||||
| 6 | 32952.30 | 1350023000 | 4.449E+13 | *3.67 | 1.631E+14 | 1.631E+02 | |||
| 12 | 65904.60 | 1350023000 | 8.897E+13 | *3.67 | 3.262E+14 | 3.262E+02 | |||
| 60% of C converted to CO2 (e.g., 3.32 E 14 * 0.60) | |||||||||
| 6 | 9.787E+13 | 1.664E14*.60 | |||||||
| 12 | 1.9574E+14 | 3.329E14*.60 | |||||||
| 340 - 260 ppm = 80 ppm change in CO2/10000 = 0.008% change | |||||||||
| 5.0 E18 kg * 0.00008 = 4.0 E14 kg increase of CO2 in the atmosphere | |||||||||
| 1.997E14 / 4.0 E 14 kg change in CO2 (due to OM) | |||||||||
| % change due to CO2 from Organic Matter Breakdown | |||||||||
| 6 | 0.245 | 9.98E13/4.00E14 | |||||||
| 12 | 0.489 | 1.99E14/4.00E14 | |||||||
| ppm increase over 150 years due to the 3% change in Organic Matter World Wide | |||||||||
| 6 | 19.574 | 80*.25 | |||||||
| 12 | 39.148 | 80*.49 | |||||||
| REFERENCES | |||||||||
| Ranney, R.W. 1969. An organic carbon-organic matter conversion equation for Pennsylvania surface soils. Soil Sci. Soc. Am. Proc. 33:809-811. | |||||||||
| Wallace, Arthur, Garn A. Wallace and Jong W. Cha. 1990. Soil organic matter and the global carbon cycle. J. Plant Nutr. 13:459-466. | |||||||||
| chem.bu.edu/generalchemistry/101-fall-94/9a.html | |||||||||
| www.owlnet.rice.edu/~monat/airweight.html | |||||||||
| Brimblecombe, P. 1986. Air Composition and Chemistry. ______ press | |||||||||