摘要：Agriculture is one of the major global sources of greenhouse gas (GHG) emissions; on-farm sources alone emit roughly 60% of all nitrous oxide and 50% of all methane emissions (WRI, 2012). Modern agriculture is more intensified, mechanised and modernised than ever before, and there are increasing demands for more fuel, electricity, farm machinery and agrochemicals. In addition, many associated off-farm operations require significant energy inputs, resulting in even more GHG emissions [1-12]. As a result, from 1990 to 2005, GHG emissions from agriculture increased by 14%, with average annual increase in emissions of 49 Mt CO2e/yr (US-EPA 2006). Significant reductions in farm inputs are needed to reduce farming costs and to curb increasing GHG emissions. Cropping systems that minimise farm input related costs and GHG emissions and also improve the sustainability of the soil system are the demand of this century.
