Background
The concentration of carbon dioxide (CO2) in the atmosphere has been increasing during the last few decades at an accelerated rate. Its contribution to increased atmospheric radiative forcing and its influence on decreasing upper atmospheric ozone levels have raised interest in evaluating its sources and sinks (Perdomo et al. 2009). Soil is considered to be the largest terrestrial organic carbon stock which currently contains as much as twice the amount of carbon as atmospheric CO2 and three times that of global above-ground vegetation (Powlson et al. 2011). This large carbon pool is greatly influenced by soil management (Baker et al. 2007). Agricultural soils are intensely managed and are subjected to different practices like tillage, addition of fertilizers, manure and variable cropping intensity (Ellert and Janzen 1999).Conservation tillage or notillage has been proposed as a means of increasing carbon sequestration in agricultural soils (Six et al. 2004).
Long term monitoring of soil carbon stocks on no-till-managed agricultural soils is a well-recognized practice aimed at evaluating the real impact of no tillage or conservation tillage on soil carbon sequestration (Six et al. 2004). Quantifying the loss of soil organic carbon upon tillage reversal on a long term non-tilled soil could therefore be a good measure of the loss of sequestered soil organic carbon. Measurement of change in soil carbon storage over time usually provides a good estimate of long term soil carbon losses following tillage but unfortunately this technique often fails to capture large but fleeting CO2 effluxes as a result of episodic tillage events (Ellert and Janzen, 1999). Moreover, soil carbon losses may be very high right after a tillage event and these additional carbon losses might disappear with time following tillage or consecutive tillage events in the following years (Fortin et al. 1996).
The government of Alberta has recently created Conservation Agriculture Protocols for Greenhouse Gas Offsets which allow large industrial emitters of greenhouse gases to offset their emissions by purchasing offset credits (Goddard et al. 2009). With this protocol, there is an Assurance Factor to account for “oneoff” tillage operations that a farmer might execute to control weeds or because of crop failure, etc. This Assurance Factor assumes that the rate of carbon loss from tillage of a conservation tillage soil is the same as the sequestration rate following conversion from conventional to conservation tillage. However, this assumption has not been tested. A big question is whether rates of carbon loss following tillage reversal are the same as rates of carbon sequestration when zero tillage management was established on conventionally tilled soil.
The government of Alberta has recently created Conservation Agriculture Protocols for Greenhouse Gas Offsets which allow large industrial emitters of greenhouse gases to offset their emissions by purchasing offset credits (Goddard et al. 2009). With this protocol, there is an Assurance Factor to account for “oneoff” tillage operations that a farmer might execute to control weeds or because of crop failure, etc. This Assurance Factor assumes that the rate of carbon loss from tillage of a conservation tillage soil is the same as the sequestration rate following conversion from conventional to conservation tillage. However, this assumption has not been tested. A big question is whether rates of carbon loss following tillage reversal are the same as rates of carbon sequestration when zero tillage management was established on conventionally tilled soil.
Research Objectives
1. Measurment of CO2 emission from two soil types with high and low level of organic matter in regards to tillage strategies
2. To study that if soil fertilization has significant effect on CO2 emissions from soil
3.To study CO2 emission trends in growing season
Expected Results
1. CO2 emissions are greater following tillage reversal from both Black Chernozemic and Gray Luvisolic soils managed under long term no-till.
2. Nitrogen fertilizer application stimulates higher CO2 emissions following tillage reversal on both of the aforementioned soil types.
3. Tillage reversal causes greater CO2 emissions from organic matter-rich Chernozemic soils than that from relatively organic matter poor Luvisolic soils.
2. Nitrogen fertilizer application stimulates higher CO2 emissions following tillage reversal on both of the aforementioned soil types.
3. Tillage reversal causes greater CO2 emissions from organic matter-rich Chernozemic soils than that from relatively organic matter poor Luvisolic soils.
Disclaimer: All datasets, events and parameters have been manipulated and/or randomly generated.