Field measurements of soil CO2 efflux in Heteropogon contortus do minated grassland of semi-arid eco-system.
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Date
2011-05
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Abstract
Seasonal changes in soil respiration (SR), soil temperature (ST) and soil moisture (SM) were compared
between a barren land with no vegetation (control) and grassland dominated by Heteropogon contortus (L.) of a
semi-arid eco-system during 2005-2006. A statistically significant (p<0.001) seasonal change in SR was
observed between the two sites. The variation characteristics of soil CO2 efflux rates were observed during wet
periods along precipitation gradients and it was consistently higher in grasslands than in control. A maximum soil
CO2 efflux of 13.35 ± 0.33 Amol m-2 s-1 in grassland and 7.33 ± 0.8 Amol m-2 s-1 in control was observed during
rainy season-II, i.e., from October to December, a minimum of 1.27 ± 0.2 Amol m-2 s-1 in grassland and 0.67
± 0.5 Amol m-2 s-1 in control during summer season, i.e., from March to June. A positive significant relation
observed between soil respiration and soil moisture (r2 above 0.8) and no significant relation was observed
between soil CO2 efflux and soil temperature (r2 below 0.3). In water-limited semi-arid ecosystem, rewetting of
the soil due to precipitation events triggered the increased pulses of soil respiration especially in grassland when
compared to the barren land. The observed soil respiration rates during summer and after the subsequent
precipitation events strongly indicated that the soil water-deficit conditions reduce the efflux both in barren land
(control) and in grassland of semi-arid eco-system.
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Keywords
Semi-arid climate, Soil CO2 efflux, Soil respiration, Heteropogon contortus, Seasonal variation
Citation
Saraswathi S Gnaana, Paliwal Kailash. Field measurements of soil CO2 efflux in Heteropogon contortus do minated grassland of semi-arid eco-system. Journal of Environmental Biology. 2011 May; 32(3): 333-337.