Organic methods, which rely on crop rotation, manure and compost in place of fertiliser, are far less intensive.

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Although organic yields averaged 20% less than those from the conventional plots, the input of fertiliser and energy was reduced by between 34% and 53%, and pesticide use by 97%.

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However, heavy machinery and herbicides are required to prepare a seedbed, and with several applications of fertiliser and sprays the field will see far more machinery use than any similar organic crop.

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