|
|
Abstract
Nkongolo,
N.V., R.M. Paro., N.O. Hoilett, S. J.
Adisa, K. Schmidt, S.S. Johnson and F.
Eivazi. 2008. Improved quantification of CO2, CH4, and N2O fluxes from soil in agricultural
fields in central Missouri. JEMREST 5:176-189.
As it is the case for
soil chemical and physical properties, greenhouse gas fluxes also exhibit
tremendous variability across fields. However, because of the cost of
collecting numerous samples, measurements of fluxes across agricultural
fields are often limited to few points. The average value of point
measurements is later used to calculate the total flux for the sampled area
This approach may result in an over or underestimation of the total flux. The
objective of this study was to assess if geographic information systems (GIS)
could improve the estimation of N2O, CH4 and CO2 total field fluxes from soil in agricultural
fields in central Missouri.
We sampled for N2O,
CH4 and CO2 fluxes in a pasture, fitted variogram models
to fluxes data, predicted fluxes at un-sampled locations by kriging or
inverse distance weighing, produced fluxes maps and classified them according
to fluxes distribution zones. Thereafter, we calculated a total flux (TF) by
multiplying field minimum and maximum flux value for each gas by the total
area sampled. Then, we also computed a GIS-based improved total field flux
(ITFF) as the sum of “TF” for each flux distribution zone for
each gas at each sampling period. Results showed that “TF” method
over-estimated (up to 800%) the total minimum and maximum flux for N2O, CH4 and CO2 as compared to “ITFF”. Our
approach provides in an improved quantification of greenhouse flux. The
approach can be extended to other soil and environmental parameters.
|
