Soil compaction and wetness effects on efflux of greenhouse gases

Abstract

Excessive soil compaction exacerbates physical, chemical and biological processes which influence
aeration, emission of greenhouse gases (GHG) and other agricultural and environmental implications.
An incubation involving bulk density (Ïb) in the range of 1.2-1.8 Mg m-3 and field moisture capacity (FC)
of 100%, 50% and 25% for 4 week. The results indicated that emissions of CO2, CH4 and N2O were the
highest on 7th day and reduced thereafter. However, N2O flux at Ïb of 1.4 Mg m-3 and CH4 at Ïb 1.6 Mg
m-3 and 1.8 Mg m-3 increased with duration of incubation. The flux of CO2 was always higher at moderate
compaction (Ïb 1.4 Mg m-3) and moisture (FC-50%). In general, CO2 flux was more affected by soil moisture
content than by compaction. However, CH4 flux was more with higher compaction and moisture which
increased sharply on the 7th day and remained constant up to 21 days. Flux of N2O was the highest at Ïb
of 1.8 Mg m-3 and 25% of FC. Irrespective of Ïb and moisture regimes, N2O flux increased sharply on the
7th day and remained constant up to 28th day. The fluxes of N2O and CO2 were negatively correlated with
soil moisture content and Ïb. However, flux of CH4 was positively correlated with soil moisture and Ïb.