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Abstract
Johnson, S.S., N.V.
Nkongolo, R.M. Paro, and F. Eivazi. 2007. Spatial variability of soil thermal
properties and CO2, CH4, and N2O emissions from a pasture in central Missouri. JEMREST 3:314-322.
DOI: 10.4029/2007jemrest3no128
Knowledge
of the spatial variability of greenhouse gas emissions and soil properties is
helpful in designing strategies for reducing gases emissions. We studied the
spatial variability of CO2, CH4, and N2O fluxes and assessed their relationship with soil thermal
properties in a pasture at Lincoln
University’s
Carver Farm. To collect soil air samples for determinations of CO2, CH4, and N2O fluxes,
twenty chambers of 0.30 m long and 0.20 m diameter were installed in a 1.42
hectare and their locations were recorded with a GPS. Soil air sampling
process consisted in closing the chamber top and two ventilation holes,
collecting air samples at thirty minutes intervals and analyzing them within
2 hours with a Shimadzu Greenhouse Gas GC. Soil thermal properties were
directly measured using a KD2 probe.
Results showed that CO2 and N2O emissions
ranged from 2.1 to 173.6 mg C-CO2 m-2 h-1 and -21.8 to 283.3 mg N-N2O m-2 h-1, respectively. CH4 uptake ranged from 8.31 to 133.1 ug
C-CH4 m-2 h-1. N2O, CO2, and CH4 responded to variogram models and were
correlated with soil thermal properties.
Gases fluxes showed shifts from high emissions to low emissions at
various sampling times. This study provides useful information in understanding
gases fluxes trends and their controlling factors.
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