This program will discuss the results of work sponsored by NETF and NRCS and performed by CFRA staff from 2002 to 2007. What do farmers need to know to…
Bulk density ----------------- Soils vary in weight per given volume. Healthy, biologically active soils weigh around 1 tonne per cubic metre, whilst heavy clays that contain little or no organic matter (such as clays that might be used for brickmaking) weigh up to 1.8 tonnes per cubic metre. In general, healthy soils are more porous, have more air holes and contain more light weight organic matter than biologically degraded soils. For this example we have chosen to us a commonly occurring bulk density of 1.4 tonnes per cubic metre. % Change in Soil Organic Matter -------------------------------------------- Once the mass of a soil is calculated by multiplying volume by Bulk Density, it is possible to calculate the change in mass per % change in Soil Organic Matter (SOM). At any Bulk Density the change remains the same, regardless of whether the soil improves from 1% SOM to 2% or from 10% SOM to 11%. Soil Organic Matter contains approximately 58% elemental Carbon Converting Carbon Dioxide (CO2) to Carbon ------------------------------------------------------------ On the Periodic Table, carbon has a weight of 12 and oxygen 16. Carbon dioxide, which contains 2 x oxygen and 1 x carbon therefore weighs 44. To achieve a 1 unit move in carbon from carbon dioxide the conversion ratio is 44/12 or 3.67. For every tonne of carbon sequestered 3.67 tonnes of carbon dioxide must be removed from the atmosphere. The full maths for this slide ------------------------------------ 10,000 sq. metres x 33.55 cm = 3,355 cubic metres per hectare 3,355 cubic metre x 1.4 BD = 4,697 tonnes of soil per hectare to a depth of 33.5 cm A 1% change in this mass = 46.97 tonnes Which contains 46.97 x 58% = 27.24 tonnes of Carbon Captured Carbon 27.24 tonnes x 3.67 = 99.98 tonnes CO2