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Fichier: 

energy.&.enviro.burdens.pdf

Type: 

ACV complète non disponible sur le web (Résumé)

Comparative: 

oui

Année de publication: 

2006

Langue: 

Anglais

Code: 

Gardening/Agriculture/Industry

Code: 

Food, Plants

Produit: 

Agricultural and horticultural products

About 27% less energy was used for organic wheat and rape production compared with non- organic, but there was little difference with potatoes. The large reduction in energy used by avoiding synthetic N production is offset by lower organic yields, which increases the absolute contribution of energy for field work. Field work for combinable crops is always more for organic owing to the need for extra operations for weed control.

GWP is only 2–7% less for organic than non-organic field crops, reflecting the need for N supply to equal N take-off and the consequent emissions to the environment as nitrous oxide to air and nitrate to water.

Most organic animal production reduces primary energy use by 15% to 40%, but organic poultry meat and egg production increase energy use by 30% and 15% respectively. Despite the lower energy needs of organic feeds, this benefit is over-ridden by lower bird performance. More of the other environmental burdens were larger from organic production, but ARU was mostly lower (except for poultry meat and eggs) and most pig meat burdens were lower. GWP from organic production ranged from 42% less for sheep meat to 45% more for poultry meat.

Land use was always higher in organic systems (with lower yields and overheads for fertility building and cover crops), ranging from 65% more for milk meat to 160% for potatoes and 200% more for bread wheat, but the latter is a special case as only part of a crop meets the specified bread-making protein concentration. Organic tomato yields are 75% of non-organic. Thus, the lowest yielding organic, on-the-vine, specialist tomatoes incur about six times the burden of non- organic, loose classic.