Soil compaction and wetness effects on efflux of greenhouse gases

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 (ρb) 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 ρb of 1.4 Mg m−3 and CH4 at ρb 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 (ρb 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 ρb of 1.8 Mg m−3 and 25% of FC. Irrespective of ρb 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 ρb. However, flux of CH4 was positively correlated with soil moisture and ρb.