The principal sources of greenhouse gas emissions on mixed cotton farming enterprises include CO2 from decomposition of crop residues added to soils and native soil organic matter, and the combustion of fuels. Nitrous oxide (N2O) with a Global Warming Potential (GWP) of 296 (i.e. one N2O molecule is equivalent to 296 CO2 molecules in terms of its ability to warm the atmosphere) is also produced during transformation of both mineral (fertiliser) and organic (legume) nitrogen applied to soils. The latter also includes the decomposition of crop & pasture residues. Nitrous oxide is also produced in smaller quantities in association with atmospheric deposition of nitrogen and nitrate leaching (the latter usually restricted to irrigated soils or high rainfall regions). Where urea is applied, CO2 is also released to the atmosphere. In the case study outlined in this paper, urea based fertilisers were not applied. If animals are included in the farming enterprise, methane emissions (CH4) also need to be included. Methane has a GWP of 23