Agriculture Management Effects on Soil Carbon Sequestration in Eastern Canada
A large amount of C is stored in soil organic matter. (SOM). Over most of the earth’s land surface, the quantity of C as SOM (1400–1500 Gt C) exceeds by a factor of two or three the amount stored in living vegetation (560 Gt C) (Schlesinger, 1990). The contribution of CO2 released to the atmosphere from farmland has been estimated to represent 20–25% of the total amount released due to human activity (Duxbury et al, 1993). However, the estimation of the quantities of CO2 released from farmlands is subject to many uncertainties. Most studies on the losses of SOM from agricultural soils often consider only the surface layer in terms of % C, rather than total C in the whole soil profile which requires measurement of bulk density (Duxbury and Mosier, 1993). It is therefore difficult to separate increased mineralization rates from a possible dilution and redistribution of SOM in the profile, which could be due to tillage, erosion or other disturbances of the ecosystem. There is therefore a need for more information on the quantitative distribution of C throughout the whole soil profile.
KeywordsSoil Organic Matter Soil Organic Carbon Soil Profile Crop Residue Soil Carbon Sequestration
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