[AngryData]

For agriculture, the tractors themselves are producing negligible CO2. Most all farm emissions come from fertilizer and right now we produce nearly all of our commercial fertilizer from fossil fuels. In order to synthesize fertilizer from the air and other renewable sources we are looking at a near 100 fold increase in power requirements. IE, our current total world energy production would have to go almost 100% towards fertilizer production to produce what we currently use. And we aren't anywhere near producing that much renewable energy yet either. We are basically fertilizing our fields with fossil fuels, and that fossil fuel fertilizer accounts for around 60% of the world's total crop yield.