Energy use in organic farming

Summary in the original language of the document

Limited fossil fuel reserves, growing populations and rising input prices highlight the importance of increasing the efficiency of food production systems and reducing GHG emissions. GHG emissions from fossil fuel use in agriculture are important along with the production of CH4 and N2O. In this context, organic agriculture has developed with an emphasis on resource use efficiency. The relative energy efficiencies of organic and non-organic farming were compared through a review of 50 studies including direct on-farm use and embedded energy in inputs.
Organic systems use less fossil-fuel energy on a unit of land area basis for nearly all crop and livestock types, although results are more variable per unit of product. In many cases the difference can be attributed to the high energy requirements for the manufacture of nitrogen fertiliser. Organic farms avoid this input by sourcing most nitrogen input through biological fixation by legumes. Despite this, lower yields and higher energy requirements for weed control can make some organic cropping systems perform worse. Higher feed conversion ratios and mortality rates also make some organic poultry systems less efficient per unit output. Higher human energy (labour) requirements were also found on organic farms because of increased mechanical weeding and greater diversity, but this may not be accounted for.
Overall, the review found that organic farming systems have potential to contribute towards more efficient agriculture, but with lower yields. The review also highlighted that organic systems do not offer a radical alternative, as they are still reliant on fossil fuel sources and the differences in energy use per unit of product were often marginal. Organic methods could still be applied to increase the efficiency of the agriculture sector as a whole, although energy use is only one aspect of sustainability that needs to be considered when comparing systems.