Improving Productivity

Increasing crop yields can reduce GHG emissions. The more plants grow, the more they take in CO2, part of which finds its way into the soil. Greater productivity should also lessen the demand for more land, so reducing the carbon emissions from land clearance.27 More fundamentally, attention must be paid to breaking the vicious cycle of cultivation whereby falling nutrient levels in the soil produce lower yields and less crop residues, resulting in less organic carbon in the soil that, in turn, further lowers yields.28 Crop yields can be increased through irrigation and use of fertilizers, but this will be energy intensive and lead to greater N2O emissions. The alternative, virtuous cycle builds on improved varieties, use of perennial crops, cover or catch crops grown in between seasons, or crop plants and no-till agriculture that can increase yields and the level of carbon stored in the soil.29 I present examples of these in the following pages, reflecting on their respective advantages and disadvantages.

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