Citation:
Jeremy Woods, Adrian Williams, John K. Hughes, Mairi Black and Richard Murphy, Energy and the food system, Philosophical Transactions of the Royal Society B: Biological Sciences, 27 September 2010, Volume 365, Number 1554, Pages 2991-3006.
Abstract:
Modern agriculture is heavily dependent on fossil resources. Both direct energy
use for crop management and indirect energy use for fertilizers, pesticides and
machinery production have contributed to the major increases in food production
seen since the 1960s. However, the relationship between energy inputs and yields
is not linear. Low-energy inputs can lead to lower yields and perversely to
higher energy demands per tonne of harvested product. At the other extreme,
increasing energy inputs can lead to ever-smaller yield gains. Although fossil
fuels remain the dominant source of energy for agriculture, the mix of fuels
used differs owing to the different fertilization and cultivation requirements
of individual crops. Nitrogen fertilizer production uses large amounts of
natural gas and some coal, and can account for more than 50 per cent of total
energy use in commercial agriculture. Oil accounts for between 30 and 75 per
cent of energy inputs of UK agriculture, depending on the cropping system. While
agriculture remains dependent on fossil sources of energy, food prices will
couple to fossil energy prices and food production will remain a significant
contributor to anthropogenic greenhouse gas emissions. Technological
developments, changes in crop management, and renewable energy will all play
important roles in increasing the energy efficiency of agriculture and reducing
its reliance of fossil resources.
Keywords: energy in agriculture; fossil energy; agricultural greenhouse gas
emissions; land use; agroforestry; policy